Load Despatch and Communication System.pptx

Load Despatch

1. Load Despatch and Communication System

2. Sub-titles Grid management : Problems and solutions Load despatch centre : Functions SCADA and RTU Energy Management System ; Functions Load Forecasting, Load management and Load shedding Hydro-Thermal Generation Scheduling Voltage and Frequency Control Reactive Power Management

3. Sub-titles Tariff and Role of Tariff in System Operation Import/Export of Energy Operation co-operation Communication System;PLCC,Microwave,Fibre Optics,Leased lines, Satelite,V -sat Communication, Integrated communication System Telemetry,Tele -control and tele-protection Protocol details Grid Disturbances: case studies

4. Grid management : Problems and Solutions Due to the ever-increasing demand and growth in the power system , there are several challenges power grid operators need to face: 1. Growing amount of renewable energy sources It is expected that by 2025, more than 50 % of generated energy will be covered by renewables. In comparison, the amount of green energy capacity in 2024 represented 45 % of the total installed capacity . However, connecting renewable energy sources (RES) with the grid is not as simple as it may seem and their effectiveness is entirely dependent on weather conditions. From this point of view, RES are considered an unstable energy source and their operation, without an advanced management system, can cause a serious grid imbalance. Solution: Smart Control Artificial intelligence can improve prediction systems and thus allow for more accurate weather or energy consumption forecasts. With this approach, utility companies can improve the planning of their clients' electricity needs and smart energy management solutions can turn green energy into a reliable alternative to fossil fuels.

5. 2. Electricity transmission losses Electricity distribution over long distances increases the temperature within power lines and thus causes significant energy losses in the form of heat. In the end, these losses are paid for by everyday electricity consumers. Solution: Energy decentralization A robust Transmission and sub-transmission network shift from electricity production in a few big close to the load centers would result in reduction in the Distribution network and reduction in losses.

6. 3.Power theft: Power theft has been one of the major issues in India Power system. A few ways to help prevent the power theft are the use of overhead lines that are insulated and the LT overhead wires used for distribution of power could be replaced with insulated cables in order to minimize the theft of energy through hooking. The conventional energy meters could be replaced with digital tamper proof meters and the use of prepaid card is yet another solution to eradicate theft of energy.

7. 4. Inadequate Grid Infrastructure: For India to continue along its path of aggressive economic growth, it needs to build a modern, intelligent grid. It is only with a reliable, financially secure Smart Grid that India can provide a stable environment for investments in electric infrastructure - a prerequisite to fixing the fundamental problems with the grid. Lot of budget support and Private participation shall be the immediate solution for the issue.

8. 5. Low metering efficiency: The commercial losses are mainly due to low metering efficiency, theft & pilferage. This may be eliminated by improving metering efficiency, proper energy accounting & auditing and improved billing & collection efficiency. Fixing of accountability of the personnel / feeder managers may help considerably in reduction of AT&C loss.

9. 6. Power outages The two most common causes of blackouts are extreme weather conditions and time-worn power lines. Serious cases of power outages threaten millions of people and Industry in past and already caused large scale damages in the country on several occassions . Besides paralyzing life within the affected areas, a huge blackout can result in electronic device damage and important data loss. Solution: Increased energy self-sufficiency Backup sources, such as batteries, can offer long-lasting protection in case of power outages and ensure continuous operation of crucial equipment. When combined with a renewable energy source, the restoration can be fast and damages can be minimized. Further, the renovation and upgradation plans for the power system components should be put in place.

10. 7. Grid modernization While the operating lifetime of power lines is not eternal and the renovation or building of new power lines is costly, there is a constant need to increase its capacity. Solution: Energy decentralization As mentioned above, local energy production and consumption lowers the amount of electricity distributed through the power grid. Therefore, the transmission losses are lower and less burdened power lines last longer.

11. 8. Threat of cyber attacks Digitalization of the energy sector has its side effects as well. There have already been cases detected when a group of hackers infiltrated systems of energy companies and exposed thousands of households to a controlled blackout. Solution: Blockchain The potential of distributed databases to eliminate cyber attacks proved to be so efficient that even international financial institutions e.g. J.P. Morgan and Nasdaq consider its implementation. Similarly, as during energy generation decentralization in which the responsibility for the grid operation is not in the hands of a single supplier, distributed databases mean that an attack on one single point in the grid, e.g. one power plant, cannot interfere with the operation of the entire system

12. 9.Threat of terrorist attacks Devastation of power lines can take much longer to repair. Solution: Microgrids Or, simply said, self-sufficient energy communities. If a terrorist group decided to stop the energy supply on a big scale, an attack on a huge number of microgrids would be needed.

13. ENERGY CONTROL CENTRE(LOAD DESPTCH CENTRE) The energy control center (ECC) has traditionally been the decision-center for the electric transmission and generation interconnected system. The ECC provides the functions necessary for monitoring and coordinating the minute-by-minute physical and economic operation of the power system. In the country , there are five interconnected regions: Northen , North-eastern, Eastern, Western and Southern but there are many state control areas, with each control area having its own ECC. Maintaining integrity and economy of an inter-connected power system requires significant coordinated decision-making. So one of the primary functions of the ECC is to monitor and regulate the physical operation of the interconnected grid. A Schematic view of the ECC is illustrated in the figure below. Where we can identify the substation, the remote terminal unit (RTU), a communication link, and the ECC which contains the SCADA cum Energy management system (EMS). The EMS provides the capability of converting the data received from the substations to the types of screens observed.

14. Energy ManAgement System EMS is a computer-based Operation and Control System. It is used in mentoring and controlling the system in real time. It receives large amount of information from power Systems through SCADA. It selectively uses Information from SCADA for computation and analysis. It Send back ‘important control signals’ to the System through SCADA. EMS has different names, namely 1) ECC: Energy Control Centre, 2) Load Dispatch Centre, 3) DSM: Demand side Management, 4) DMS: Distribution Management System, etc. The main functions of these are to operate the power systems in real time.

15. Evolution of EMS: The evolution of EMS has a long past. It has started with control centers in 1960s to fully developed energy management systems 1960 – Termed as Control Centre’s (CC): These control centers were initially termed a load dispatch centres . The important task was to control the power generation and load demand as to match the generation with load demand. Even today, the term load dispatch centres are widely used. 1990 – Energy Management Systems (EMS): In EMS, the main task was to manage the energy through various techniques like load management (LM), demand side management (DSM), distribution management systems (DMS). EMS are computer based programs that perform both computational tasks as well as decision making tasks so as to assist the operator for real time operation and control.

16. Objectives OF EMS: Primary Objectives: Security and Stability of the system Secondary Objectives: Optimal and Economic Operation and Control Tertiary Objectives: Operational Planning and Maintenance Scheduling The three objectives are executed at different levels by the operator in a control centre . While the first objective is automatic or closed loop control without the intervention of the operator, the secondary and tertiary are performed with the aid of the operator. In energy management systems, voltage magnitudes and power flows over the lines are continuously monitored through SCADA, to check for violations. The violations in voltage are addressed mostly by preventive control actions, while the power flow violations are addressed by means of corrective actions.

17. Primary Objectives: Maintaining the power system in a secure and stable operating state by continuously monitoring the power flowing in the lines and voltage magnitudes at the buses. Maintaining the frequency within allowable limits. Maintaining the tie-line power close to the scheduled values.

18. Secondary Objectives: Economic Operation of the power systems through real time dispatch and Control. Optimal control of the power system using both preventive and corrective control actions. Real time Economic Dispatch through real power and reactive power control

19. Tertiary Objectives: Optimization of the power system for normal and abnormal operating scenarios. Optimal control of the power system by appropriate using both preventive and corrective control actions Maintenance scheduling of generation and transmission systems.

20. Functions and Benefits of EMS: The important benefits of an EMS can be addresses as the following functions: Control functions: Real time monitoring and control functions. Automatic Control and automation of a power system like Automated interfaces and electronic tagging Efficient automatic generation control and load frequency control. Optimal automatic generation control across multiple areas Tie -line control. Operating functions Economic and optimal Operation of the generating system. Efficient operator Decision Making Improved quality of supply

21. Functions and Benefits of EMS: Optimization functions Optimal utilization of the transmission network Power scheduling interchange between areas. Optimal allocation of resources Immediate overview of the power generation, interchanges and reserves Planning functions Improved quality of supply and system reliability Forecasting of loads and load patterns Generation scheduling based on load forecast and trading schedules Maintaining reserves and committed transactions Calculation of fuel consumption, production costs and emissions

22. EMS Architecture: The below figure shows the main important entities of power systems, EMS and SCADA. EMS and SCADA are two important entities in the real time monitoring, operation control of power systems. The flow of Power and information between the three modules can be observed. While Power (unidirectional) flows from Power Systems through SCADA to EMS. Information flow (bi directional) SCADA forms the interface between Power Systems and EMS. The power system data, both continuous and discrete, is collected by SCADA and selectively sent to the EMS. EMS is a computerized control of power system consisting of several application programs which are run / executed by the operator so as to maintain the power system in a secure and stable operating state. EMS consists of several programs interconnected in a particular fashion so as to obtain the solution in real time.

23. Power and Information flow between Power systems, SCADA and EMS

24. Practical EMS Figure next shows the actual implementation of Power System Model, SCADA AND EMS The power system consists of components of three phase generators, transformers, transmission lines and loads. The SCADA modules consist essentially of hardware for measurement monitoring, control and protection of the power systems. SCADA monitors information from the power system through PT, CT, etc., collects data and sends them to the EMS. Both Analog (continuous) data and digital (discrete) information are collected by the Remote Terminal Units (RTU). EMS consists of a network of computers or work stations which perform computational tasks for decision making in real time operation and control. Both On-line and Off-Line functions can be performed in an EMS. On line functions include mainly closed loop control functions like automatic generating control (AGC), load frequency control (LFC), voltage reactive power control (volt-var control). Open loop functions like Economic Dispatch and Operator load flow, state estimation, security assessment, etc are also performed in real time as on line functions.

25. COMPONENTS OF EMS and SCADA

26. Working of EMS: The important working of an EMS is given below: Real time monitoring and control over the whole distribution network. Enhanced customer service through a complete outage management package including trouble call taking, fault localization and restoration as well as outage statistics and customer notification. Efficient work order handling via the built-in work management tools. Better crew and resource management including support for crew scheduling and tracking, dispatching and assignments as well as follow-up and reports. Optimal network utilization using the State Estimator functionality for optimal feeder reconfiguration and loss minimization in balanced networks Better support for all reporting with retrieval of historical data archived in a data warehouse

27. SCADA In the realm of power systems, SCADA serves as a centralized system that enables operators to monitor, analyze, and control various aspects of power generation, transmission, and distribution. It acts as the nerve center, facilitating seamless communication between different components of the power grid. SCADA consists mostly of hardware components, which measure the quantities (Voltage, current, power, etc..) from various meters. SCADA consists of collection of information from meters distributed throughout the area through Remote Terminal Units (RTUS).

28. Evolution of SCADA: The evolution of SCADA started with monitoring and data acquisition systems plants followed by control. These have been used prior to EMS. The main tasks of SCADA were to continuously measure and monitor parameters for checking limit violations and to ensure reliable and safe operation of the system being controlled. The earlier tasks of SCADA were mostly monitoring with gradual control tasks coming into picture. It becomes more beneficial when EMS and SCADA are used together.

29. Components of SCADA Systems Supervisory Control: SCADA systems allow operators to supervise and manage the overall functioning of power systems. They can remotely control devices, adjust settings, and respond to emergencies in real-time. Data Acquisition :One of the fundamental roles of SCADA is data acquisition. It collects data from sensors, meters, and other devices deployed throughout the power grid. This data includes voltage levels, current flows, equipment status, and environmental conditions. Human-Machine Interface :The human-machine interface (HMI) provides operators with a graphical representation of the power system. It offers intuitive tools for monitoring and controlling various processes, enabling operators to make informed decisions quickly.

30. Benefits of SCADA in Power Systems Enhanced Monitoring and Control :SCADA systems provide real-time visibility into power system operations, allowing operators to identify issues promptly and take corrective actions. This leads to improved reliability and stability of the grid. Improved Efficiency :By optimizing the use of resources and minimizing downtime, SCADA helps power utilities operate more efficiently. It enables predictive maintenance, asset optimization, and demand response, leading to cost savings and higher productivity. Faster Response to Faults :In case of a fault or outage, SCADA systems enable rapid detection and isolation of the affected area. This minimizes the impact on customers and reduces the duration of service interruptions.

31. Applications of SCADA in Power Systems Substation Automation :SCADA systems are widely used for substation automation, where they monitor and control equipment such as circuit breakers, transformers, and switches. This improves the reliability and efficiency of substations while reducing the need for manual intervention. Distribution Management :SCADA plays a critical role in distribution management by optimizing the flow of electricity from substations to consumers. It helps utilities balance supply and demand, manage voltage levels, and minimize losses in the distribution network. Load Management :By monitoring energy consumption patterns in real-time, SCADA systems enable utilities to implement demand-side management strategies. This includes load shedding, peak shaving, and dynamic pricing to optimize the use of resources and ensure grid stability.

32. Remote Terminal Units (RTUs) SCADA systems utilize remote terminal units (RTUs) to interface with field devices such as sensors, relays, and switches. RTUs collect data from these devices and transmit it to the central control center, enabling remote monitoring and control. The monitoring equipment is normally located in the substations and is consolidated in what is known as the remote terminal unit (RTU). Generally, the RTUs are equipped with microprocessors having memory and logic capability. Older RTUs are equipped with modems to provide the communication link back to the ECC, whereas newer RTUs generally have intranet or internet capability. Relays located within the RTU, on command from the ECC, open or close selected control circuits to perform a supervisory action. Such actions may include, for example, opening or closing of a circuit breaker or switch, modifying a transformer tap setting, raising or lowering generator MW output or terminal voltage, switching in or out a shunt capacitor or inductor, and the starting or stopping of a synchronous condenser. Information gathered by the RTU and communicated to the EMS includes both analog information and status indicators. Analog information includes, for example, frequency, voltages, currents, and real and reactive power flows. Status indicators include alarm signals (over-temperature, low relay battery voltage, illegal entry) and whether switches and circuit breakers are open or closed. Such information is provided to the ECC through a periodic scan of all RTUs.

33. Communication technologies: The form of communication required for SCADA is telemetry . Telemetry is the measurement of a quantity in such a way so as to allow interpretation of that measurement at a distance from the primary detector. The distinctive feature of telemetry is the nature of the translating means, which includes provision for converting the measure into a representative quantity of another kind that can be transmitted conveniently for measurement at a distance. The actual distance is irrelevant. Telemetry may be analog or digital. In analog telemetry, a voltage, current, or frequency proportional to the quantity being measured is developed and transmitted on a communication channel to the receiving location, where the received signal is applied to a meter calibrated to indicate the quantity being measured, or it is applied directly to a control device such as a ECC computer. Forms of analog telemetry include variable current, pulse-amplitude, pulse- length, and pulse-rate, with the latter two being the most common. In digital telemetry, the quantity being measured is converted to a code in which the sequence of pulses transmitted indicates the quantity. One of the advantages to digital telemetering is the fact that accuracy of data is not lost in transmitting the data from one location to another. Digital telemetry requires analog to digital (A/D) and possible digital to analog (D/A) converters. As illustrated in the earliest form of signal circuit used for SCADA telemetry consisted of twisted pair wires; although simple and economic for short distances, it suffers from reliability problems due to breakage, water ingress, and ground potential risk during faults. Improvements over twisted pair wires came in the form of what is now the most common, traditional type of telemetry mediums based on leased-wire, power-line carrier, or microwave . These are voice grade forms of telemetry, meaning they represent communication channels suitable for the transmission of speech, either digital or analog, generally with a frequency range of about 300 to 3000 Hz.

34. Communication scheme

35. PLCC and LEASED LINE Communication Leased-wire means use of a standard telephone circuit; this is a convenient and straightforward means of telemetry when it is available, although it can be unreliable, and it requires a continual outlay of leasing expenditures. In addition, it is not under user control and requires careful coordination between the user and the telephone company. Power-line carrier (PLCC) offers an inexpensive and typically more reliable alternative to leased-wire. Here, the transmission circuit itself is used to modulate a communication signal at a frequency much greater than the 50 Hz power frequency. Most PLCC occurs at frequencies in the range of 30-500 kHz. The security of PLCC is very high since the communication equipment is located inside the substations through open disconnects, i.e., when the transmission line is outaged . Often, this is precisely the time when the communication signal is needed most. In addition, PLCC is susceptible to line noise and requires careful signal-to-noise ratio analysis. Most PLCC is strictly analog although digital PLCC has become available from a few suppliers during the last few years.

36. Microwave / uhv and fibre -optics communication Microwave radio refers to ultra-high-frequency (UHF) radio systems operating above 1 GHz. The earliest microwave telemetry was strictly analog, but digital microwave communication is now quite common for EMS/SCADA applications. This form of communication has obvious advantages over PLC and leased wire since it requires no physical conducting medium and therefore no right-of-way. However, line of sight clearance is required in order to ensure reliable communication, and therefore it is not applicable in some cases. A more recent development is the use of fiber optic cable, a technology capable of extremely fast communication speeds. Although cost was originally prohibitive, it has now decreased to the point where it is viable. Fiber optics may be either run inside underground power cables or they may be fastened to overhead transmission line towers just below the lines. They may also be run within the shield wire suspended above the transmission lines. The latest is OPGW for both shielding and communication. Communication engineering is very important to power system control.

37. Challenges and Limitations of SCADA in Power Systems Cybersecurity Risks: As SCADA systems become more interconnected and digitized, they become vulnerable to cyber threats such as malware, hacking, and denial-of-service attacks. Securing SCADA networks against these threats requires robust cybersecurity measures and protocols. Compatibility Issues :Integrating SCADA systems with legacy infrastructure and emerging technologies can be challenging due to compatibility issues. Upgrading and modernizing existing systems to ensure seamless interoperability is essential for maximizing the benefits of SCADA. High Initial Costs :The deployment of SCADA systems involves significant upfront costs, including hardware, software, installation, and training. This can be a barrier for smaller utilities or organizations with limited budgets, despite the long-term benefits of SCADA.

38. Future Trends in SCADA Technology for Power Systems The future of SCADA in power systems is marked by several emerging trends: Integration with IoT and Big Data: SCADA systems will increasingly leverage the Internet of Things (IoT) and Big Data analytics to enhance predictive maintenance, optimize asset performance, and improve decision-making. Cloud-Based SCADA: Cloud computing offers scalability, flexibility, and cost-effectiveness for SCADA deployments. Cloud-based SCADA solutions enable real-time data access, remote monitoring, and seamless integration with other systems. AI and Machine Learning: Artificial intelligence (AI) and machine learning algorithms will play a crucial role in enhancing the intelligence and autonomy of SCADA systems. They will enable predictive analytics, anomaly detection, and adaptive control strategies.

39. SCADA for power transmission system: Some main functions of SCADA in electric transmission system are as follows: Re-routing services for station maintenance Service restoration Protective relay interface/interaction Voltage regulation management Load tap changer control Transformer management Real-time modeling Automatic circuit isolation control and interactive switch control display Interface real-time single-line displays On-line operation and maintenance logs Automatic system diagnostics by using system-defined controller alarms (alarm management

40. SCADA for power generating stations: The highlighted functions of SCADA in power plants include: Continuous monitoring of speed and frequency of electrical machines Geographical monitoring of coal delivery and water treatment processes Electricity generation operations planning Control of active and reactive power Boiler and turbine protection and their condition in case of thermal plant Monitoring of renewable energy farms and load dispatch planning Load scheduling Historical data processing of all generation related parameters Supervising the status of circuit breakers, protective relays, and other safety equipment Power apparatus health monitor The sequence of events recordin

41. SCADA for power distribution system: Improving efficiency by maint aining a tolerable range of power factor Limiting peak power demand Trending and alarming the operators by identifying the problem spot Historian data and viewing that from remote and barely inaccessible locations Quick response to customer service interruptions Feeder automation and Load Sectionalizer Provide the ability to over-ride automatic control of capacitor banks Automated meter reading Circuit breaker control, lockout, and interlocking Continuous monitoring and controlling of various electrical parameters in both normal and abnormal conditions which may affect the quality like harmonic distortions

42. Conclusion SCADA technology continues to revolutionize the power industry by providing advanced monitoring, control, and automation capabilities. Despite facing challenges such as cybersecurity risks and compatibility issues, the benefits of SCADA in terms of enhanced efficiency, reliability, and responsiveness outweigh the drawbacks . As SCADA systems evolve with emerging technologies such as IoT, Big Data, and AI, they will play an even more significant role in shaping the future of power systems.

43. Load Forecasting Load forecasting is the process of predicting how much electricity will be needed at a given time and how that demand will affect the utility grid. It is used to ensure that enough power is available to meet consumption needs while avoiding waste and inefficiency. Electric load forecasting is key to the operational planning of power systems, and crucial for avoiding outages. Load forecasting predictions can range from short-term (hours or days ahead) to long-term (months or years ahead). The accuracy of these forecasts directly impacts the cost and reliability of the entire power system. Load forecasting is also a component of broader energy forecasting, which includes predictions for the availability and pricing of fuels such as oil and gas, as well as renewable energy sources.

44. Why is load forecasting important? Accurate load forecasting ensures there is enough electric power supply to meet demand at any given time, thereby maintaining the balance and stability of the power grid. With that reliability comes greater efficiency as well as cost savings. Load forecasting allows utilities to better manage their resources through demand response programs, which shift usage by incentivizing consumers to reduce their electricity use during high-usage times. And this kind of demand forecasting can help utilities avoid the extra costs associated with producing too much or too little electricity. Load forecast data may also be used in strategic planning decisions such as capacity expansion, infrastructure development and maintenance scheduling. For example, this data can highlight the optimal location of new power plants or transmission lines, ensuring that future demand can be met. In deregulated electricity markets, load forecasting data can also help market participants make informed bidding strategies, manage energy contracts and mitigate risks

45. Load forecasting time frames Short-term load forecasting: This covers a period up to a week and relies significantly on weather forecasts and recent load data. Short-term load forecasting, including day-ahead predictions, is particularly important for managing the power grid in real time, as it allows system operators to make decisions in the moment about how much power to generate and where to direct it. Accuracy is crucial in this context, as even small errors in forecasting can lead to wasted energy or overloaded power lines. Medium-term load forecasting: This ranges from a week to a year and is used for maintenance scheduling and fuel reserve management. It considers seasonal variations in electricity consumption as well as planned outages. Long-term load forecasting: This typically covers a period of more than one year and considers factors such as demographic changes, economic growth and energy policy impacts. Long-term load forecasting focuses on system planning and optimization, helping utilities to make decisions about where to invest in new power generation capacity and how to balance different sources of energy, such as renewable energy and traditional fossil fuels

46. How load forecasting works Load forecasting methods begin with historical load data collection. This includes data from the many factors that can affect electricity use, including weather data (temperature, humidity, wind speed), time of day, calendar variables (seasons, holidays, weekday versus weekend) and demographic factors (population density, economic activity). Load forecasting takes all of these data sets into account to create a comprehensive picture of energy demand. The forecasting model is trained using a portion of the historical data and tested for validation. Performance metrics such as Mean Absolute Percentage Error (MAPE) are used to evaluate the accuracy of the forecasts. Once the model is validated and fine-tuned, it can generate future load forecasts. These forecasts can then be used for operational planning, energy management and other decision-making activities. This is an ongoing and adaptive process: As new data becomes available, the models usually require updates or retraining to remain accurate

47. Forecasting models Once data is collected, a forecasting model is developed. Some examples of models used for load forecasting include: Regression models: Linear regression models are often used for long-term load forecasting. They relate the load demand to variables like weather conditions and economic indicators. Time series models: Autoregressive Integrated Moving Average (ARIMA) and similar models are popular for short-term load forecasting. They rely on past load data to predict future demand. Artificial intelligence (AI) models: Neural networks and support vector machines are increasingly used due to their ability to model complex non-linear relationships. Deep learning models can further improve forecasting accuracy by automatically extracting relevant features from the dataset.

48. Challenges of load forecasting Load forecasting can be valuable, but it has its limitations. One major issue is the increasing complexity of the power grid, which now includes distributed energy resources (DERs) such as solar panels and electric vehicles. These resources can be difficult to predict and integrate into load forecasting models, requiring new methodologies and input features. Another challenge is the need for accurate weather forecasting, as weather conditions can have a significant impact on energy demand. Improvements in weather forecasting technology have helped to address this issue, but there is still room for improvement

49. Load forecasting and sustainability By enabling more efficient, flexible and intelligent power system operations, load forecasting is a critical sustainability tool. It can contribute to sustainability in several ways: Renewable energy transitions: Accurate load forecasting is essential for integrating renewable energy sources like wind and solar power into the grid. These sources are intermittent, meaning their output depends on weather conditions and time of day. By accurately predicting electricity demand, utilities can better plan for fluctuations and maximize use. This can help reduce overall greenhouse gas emissions by minimizing reliance on fossil fuel-based power generation. Energy efficiency: Accurate forecasts allow electric utilities to operate their distribution systems more efficiently, based on daily or hourly load, which reduces energy waste and optimizes the overall energy supply. For instance, companies can use the information to schedule maintenance or other downtime for periods of lower demand. Demand response programs: These programs incentivize people to reduce or shift their energy consumption during peak load times, helping to balance supply and demand without needing to bring additional, potentially less sustainable, generation sources online. Grid modernization: Accurate load forecasting is crucial for smarter, more flexible grids, and future energy systems. It will enable more sophisticated grid management strategies that can accommodate distributed energy resources, electric vehicles and other new technologies

50. How technology aids load forecasting Technological advancements, particularly in machine learning and artificial intelligence, have greatly enhanced load forecasting capabilities. These technologies can handle large datasets, learn from historical patterns and adapt to new trends, improving overall forecasting accuracy. Artificial intelligence: AI can enhance load forecasting by integrating different types of models and using intelligent techniques to select and optimize them. It can also incorporate expert knowledge into the forecasting process. Machine learning: Machine learning algorithms like support vector machines and neural networks can model complex non-linear relationships between input features and load demand. They can also handle high-dimensional data, making them suitable for incorporating various factors affecting electricity use. Deep learning: A subset of machine learning, deep learning uses layered neural networks to automatically extract relevant features from raw data. This can improve forecasting accuracy, especially when dealing with large and complex datasets. Smart grid technologies: Smart meters and other smart grid technologies provide real-time, high-resolution load data. This can significantly improve the accuracy of short-term load forecasting. Big data analytics: The advent of big data technologies allows processing and analysis of massive amounts of data from various sources, including weather forecasts, Internet of Things (IoT) devices and social media.

51. Load Management and Load Shedding Load shedding is an emergency control action to ensure system stability, by curtailing system load. The emergency LS would only be used if the frequency/voltage falls below a specified frequency/voltage threshold. Typically, the LS protects against excessive frequency or voltage decline by attempting to balance real and reactive power supply and demand in the system. Most common LS schemes are the UFLS schemes, which involve shedding predetermined amounts of load if the frequency drops below specified frequency thresholds. The UVLS schemes, in a similar manner, are used to protect against excessive voltage decline.

52. Load Management and Load Shedding The LS curtails amount of load in the power system until the available generation could supply the remind loads. If the power system is unable to supply its active and reactive load demands, the under-frequency and under-voltage conditions will be intense. To prevent the post-load shedding problems and over loading, the location bus for the LS will be determined based on the load importance, cost, and distance to the contingency location. Coordination between amount of spinning reserve allocation and LS can reduce total costs that generation companies should pay in the emergency conditions .

53. Load shedding stages/steps The number of LS steps, amount of load that should be shed in each step, the delay between the stages, and the location of shed load are the important objects that is determined in an LS algorithm. An LS scheme is usually composed of several stages. Each stage is characterized by frequency/voltage threshold, amount of load, and delay before tripping.

54. objective of Power System Load Shedding An effective LS scheme is to curtail a minimum amount of load, and provide a quick, smooth, and safe transition of the system from an emergency situation to a normal equilibrium state.

55. Types of LS Scheme Under Frequency Load Shedding Scheme(UFLS) Under Voltage Load Shedding Scheme(UVLS) There are various types of UFLS/UVLS schemes: Static and Dynamic (or fixed and adaptive) LS types. Static LS curtails the constant block of load at each stage, While dynamic LS curtails a dynamic amount of load by taking into account the magnitude of disturbance and dynamic characteristics of the system at each stage. Although the dynamic LS schemes are more flexible and have several advantages, most real-world LS plans are of static type

56. Paradigms of Ls There are two basic paradigms for LS: a shared LS paradigm, and a targeted LS paradigm. The first paradigm appears in the well-known UFLS schemes, and the second paradigm in some recently proposed wide-area LS approaches. Using simulations for a multi-area power system, it is easy to illustrate the difference between these two paradigms, following generation loss in one area.

57. Paradigms of Ls Sharing load shedding responsibilities (such as induced by UFLS) is not necessarily an undesirable feature and can be justified on a number of grounds. For example, shared load shedding schemes tend to improve the security of the interconnected regions by allowing generation reserve to be shared. Further, LS approaches can be indirectly used to preferentially shed the least important load in the system. However, sharing load shedding can have a significant impact on inter region power flows and, in certain situations, might increase the risk of cascade failure. Although both shared and targeted LS schemes may be able to stabilize overall system frequency/voltage, the shared load shedding response leads to a situation requiring more power transmission requirements. In some situations, this increased power flow might cause line overloading and increase the risk of cascade failure.

58. Import and Export of Electricity Electricity is generated by generating stations and transmitted to load centers from where it is distributed to end consumers. These load centers are controlled by distribution utilities, and there is an inter-change of energy between different utilities connected to the grid. Under such scenario , there is a Receiver and a Supplier of Electricity. The Supplier is said to be an Importer and the Receiver an Exporter.

59. Schematic of Supply oR Receipt of electricity

60. Import and export of Energy Energy Delivered and Received vs. Imported and Exported Issue: Energy flow can be expressed as received/delivered or imported/exported depending on whether it is from a suppliers viewpoint or that of the consumer. Environment: Energy Delivered vs. Received Energy Imported vs. Exported Cause: The terms delivered and received may be confusing as to which direction the energy flows Resolution: From the image below, you can see that if imported by the demand customer, the energy is delivered by the utility (Energy delivered/imported/Into the load). Alternately if the demand customer is also putting power onto the grid it is exported from the customers point of view and received by the utility (Energy received /exported).

61. Import and export of power Consumers connected to the distribution utilities, though consuming active energy may or may not consume reactive energy. There may be consumers whose loads are predominantly inductive and other consumers whose loads are predominantly capacitive. There may be bulk consumers who have their own generators who operate their generators in synchronism with the grid, drawing active energy from the system or even exporting active energy into the system. The exchange of electricity is complex in such situations, and four quadrant energy measurements are needed to accurately measure the active and reactive energy under different export/import conditions for both active & reactive energy.

62. Measurement Energy measurement under such situations will depend on applicable tariff structures, and hence to cater for different tariff structures in the environment of import/export of active/reactive energy special data logging/measuring features are required in meters. In this regards there are three forms of measurements to deal with (in metering) and these are active energy, reactive energy & apparent energy. The definitions and inter-relations are explained for import/export are explained below. We need to understand the definition of power flow. Power flow is always measured with respect to the Voltage, and the Voltage at the point of measurement is taken as reference vector for defining the direction of power flow. The angular position of the current vector with reference to this reference Voltage vector defines the direction of the flow for active, reactive and apparent energy.

63. measurement When we consider vectors, and we assume that the voltage vector is a reference vector (with the current vector as a variable vector based on the load), the current vector may assume any position within 3600 of the voltage vector. Suppose we now divide the 3600 into four equal quadrants of 900 each, we shall have four quadrants, and for import/export of active/reactive power, the current vector can lie in any of the four quadrants. Let us call these quadrants as Quadrant 1, 2, 3 & 4. When the current vector is placed in any of these quadrants, it forms an angle with respect to the voltage vector. The in-phase component of the current, arrived at by considering the Cosine of the angle between the voltage & current vectors is known as the active current. Multiplication of this active component of the current with the voltage gives us the active power. The integration of the active power with time gives us the active energy. The quadrature component of the current, arrived at by considering the Sine of the angle between the voltage & current vectors is known as the reactive current. Multiplication of this reactive component of the current with the voltage gives us the reactive power. The integration of the reactive power with time gives us the reactive energy.

64. Load flow

65. Power flow The point to emphasize is that the reference point or point of measurement is critical in defining whether the power (both active or reactive) is “imported” or “exported”, and it is with respect to the Voltage vector at this reference point that the definitions are made. The diagram shown below illustrates two positions of measurement and defines the import and export of electricity in accordance to the above definition. Shown in the above example is a condition where power (in general) is flowing from utility A to B. At point “A” the power is being exported and at point “B” the power is being imported. These import/export definitions are always with respect to the voltage vectors at the respective points. Hence, to be able to measure the import & export correctly, we have to see these with relation to the polarity of current connections of the meter. Incorrect current connections at the meter end will result in an “export energy” to be recorded as an “import energy” and vice versa. There is therefore a need to check connections of meters carefully in the field.

66. Power flow quadrants It is now explained how the angle of 3600 can be divided into 4 quadrants of 900 each. The active/reactive power flow is defined as per these 4 quadrants by IEC 62053-23, with the voltage at the measuring point taken as the reference vector at vertical position shown as the 00 position. The 4 quadrants are illustrated in Figure 2 below. Illustrated in the diagram are the vectorial position of the current with respect to the voltage to show what is meant by import and export for active and reactive power (or energy).

67. Power Flow quadrants

68. power flow quadrants as per IEC 62053-23 ( Fig-3)

69. Active energy The loads are comprised of a combination of inductive load, resistive load, and capacitive load. The current vector can be a maximum 90 away from the voltage vector when the load is either inductive or capacitive. It is in-phase with voltage when the load is resistive. When the angle between the voltage and active component of current is 00 degrees, the power flow is considered as “ active import”. All energy recorded by the energy meter for this type of power flow is recorded as “import energy”.The current vector lies in either quadrant 1 or 2, active energy is being consumed. The quadrants defined in IEC for active energy import are 1 & 4 as shown in figure 3. When the angle between the voltage and active component of current is 1800 degrees, the power flow is considered as “active export”. All energy recorded by the energy meter for this type of power flow is recorded as “active export energy”. The current vector lies in either quadrant 3 or 4 active energy is being generated. The quadrants defined in IEC for active energy export are 2&3 as shown in figure 3

70. REACTIVE energy There can be two types of reactive power (or energy), namely ( i ) capacitive power and (ii) inductive power. When the angle between the voltage and reactive component of current is 900 degrees, the power flow is considered as “ reactive import”. All energy recorded by the energy meter for this type of power flow is recorded as “import of reactive energy”. When the load (or power) is capacitive, the current vector leads the voltage vector. The current vector therefore lies in Quadrant 2 (or 3) depending on whether the capacitive load is import or export, and the quadrature component of the load current (capacitive current) is either at a 900 angle or 2700 with respect to the voltage vector, as shown in figure 2. This reactive energy is called Reactive energy capacitive or simply Reactive energy lead. When the angle between the voltage and reactive component of current is 2700 degrees, the power flow is considered as “reactive export”. All energy recorded by the energy meter for this type of power flow is recorded as “active export energy”. When the load (or power) is inductive, the current vector is leads the voltage vector. The current vector lies in Quadrant 1 (or 4) depending on whether the inductive load is import or export, and the quadrature component of the load current (reactive current) is either at 2700 angle or 900 angle with respect to the voltage vector as shown in figure2. This reactive energy is called Reactive energy Inductive energy or simply Reactive energy lag. Reactive energy is always defined in association with active energy. Thus reactive energy is defined for each quadrant separately. Based on the quadrant, reactive energy is either an import reactive energy or an export reactive energy. The form of reactive energies are defined as: Reference Figure 2.

71. Quadrants and implications In Quadrant 1, active energy is considered as “import”, reactive energy is also considered as “import”. This is called reactive (inductive) while active import. The power factor of this type of load is a lagging power factor. In Quadrant 2, active energy is considered as “import”, but reactive energy is considered as “export”. This is called reactive (capacitive) while active import The power factor of this type of load is a leading power factor. In Quadrant 3, active energy is considered as “export”, reactive energy is also considered as “export”. This is called reactive (inductive) while active export because this is a mirror image of inductive import (of quadrant 1). The power factor of this type of load is a lagging power factor. In Quadrant 4, active energy is considered as “export”, but reactive energy is considered as “import”. This is called reactive (capacitive) while active export because this is a mirror image of reactive import (capacitive) (of quadrant 2). The power factor of this type of load is a leading power factor. The quadrant definitions are as per IEC62053-23 is shown in figure 3, and the energy definition is as illustrated in Figure 2

72. Apparent energy Apparent energy is essentially the product of the scalar values of the voltage and current. Because the current vectors can lie in any of the four quadrants, it is not sufficient to define the apparent energy as the product of voltage and current. For every type of energy we need to define a direction to state whether the energy is being imported or exported, and the same is also needed for apparent energy. Hence defining apparent energy is not as simple as stating that it is the product of voltage & current. Apparent energy is the product of voltage & current (scalar quantities) and is considered as “apparent import” in case the current vector lies in Quadrant 1 or 2, and “apparent export” in case the current vector lies in Quadrant 3 or 4. The quantities measured by meters are the active and reactive components of the current (with angle). Hence, using these values the apparent energy can be defined in two different ways, and it is important to recognize that for each of these definitions we shall get a different value for the apparent power (or energy). In the first definition, the apparent power can either be defined as the Pythagoras Sum of “sum of inductive plus capacitive” and the “corresponding active power” . In the second definition, the apparent can be defined as the Pythagoras Sum of “sum of inductive component only” and the “corresponding active power”.

73. Apparent Energy As both the definitions do not give the same “value” for apparent power, the concept of having apparent energy tariffs can be fraught with misunderstanding. (There are of course many other technical & commercial reasons why tariffs based on apparent energy is illogical) The Apparent power is called as “import apparent power” when current vector lies in quadrants 1 or 2 as shown in figure 1. Apparent power in quadrant 3 and 4 is called as “export apparent power”, in these quadrants active power is exported As we have seen, different energies can be defined as “Active”, “Reactive” and “Apparent” based on the direction of active energy and in relation to the position of the voltage vector at the point of measurement.

74. Energy Resisters in Energy meters: The following energy registers are required to record them accordingly ( i ) Active import (ii) Active export (iii) Reactive (inductive) while active import (iv) Reactive (capacitive) while active import (v) Reactive (inductive) while active export (vi) Reactive (capacitive) while active export (vii) Apparent import (based on definition of apparent energy) (viii) Apparent export (based on definition of apparent energy)

75. Generation Scheduling Generation scheduling is also known as power scheduling or load scheduling. It’s the process of maintaining a balance between supply and demand in a power system. Specialized tools analyze the network and then the general scheduling platform optimizes the energy flow. Flow from a power-generating company can depend on constraints (e.g., carbon emissions). Power system schedules run in many stages. They can occur hourly, daily, weekly, monthly, and yearly.

76. Thermal and hydro scheduling Hydro-thermal scheduling is an optimization problem in which the dispatch of hydel and thermal plants is accomplished to ensure that the fuel cost for thermal power plants is minimized . Hydrothermal scheduling is a very vital issue in the power system operations and economics as the power system is mostly comprised of hydel and thermal power plants. Moreover, high costs of thermal power plants and intermittency of renewable energy sources shift more focus towards hydro-thermal scheduling.

77. TARRIF FLAT RATE TWO PART THREE PART ABT and UI

78. communication PLCC MOCROWAVE LEASE LINES FIBRE OPTIC, SATTELITE, V-SAT Integrated Communication System PROTOCOLS OF COMMUNICATION

79. TELEMETRY,TELEPROTECTION, Protocols

80. Load –frequency control The main objective of power system operation and control is to maintain continuous supply of power with an acceptable quality to all the consumers in the system. The system will be in equilibrium, when there is a balance between the power demand and the power generated. As the power in AC form has real and reactive components: the real power balance; as well as the reactive power balance is to be achieved. There are two basic control mechanisms used to achieve reactive power balance (acceptable voltage profile) and real power balance (acceptable frequency values). The former is called the automatic voltage regulator (AVR) and the latter is called the automatic load frequency control (ALFC) or automatic generation control (AGC).

81. Automatic Load Frequency Control: The ALFC is to control the frequency deviation by maintaining the real power balance in the system. The main functions of the ALFC are to i ) to maintain the steady frequency; ii) control the tie-line flows; and ii) distribute the load among the participating generating units. The control (input) signals are the tie-line deviation ΔPtie (measured from the tie line flows), and the frequency deviation Δf . These error signals Δf and ΔPtie are amplified, mixed and transformed to a real power signal, which then controls the valve position. Depending on the valve position, the turbine (prime mover) changes its output power to establish the real power balance. The complete control schematic is shown in Fig below which is a over simplified version for easeness of understanding the concept.

82. Schematic of alfc

83. Speed Governing System: It has mainly four major components. Speed governor: Speed governor senses the change in speed (or frequency) hence it can be regarded as heart of the system. The standard model of speed governor operates by fly-ball mechanism. Fly-balls moves outward when speed increases and the point Q on the linkage mechanism moves downwards. the reverse happens when the speed decreases. The movement of point Q is proportional to change in shaft speed. Linkage mechanism: PQR is a rigid link pivoted at Q and RST is another rigid link pivoted at S. This link mechanism provides a movement to the control valve in proportion to change in speed. It also provides a feedback from the steam valve movement. Hydraulic amplifier: It comprises a pilot valve and main piston arrangement. It converts low power level pilot valve movement into high power level piston valve movement. This is necessary in order to open or close the steam valve against high pressure steam. Speed changer: It provides a steady state power output setting for the turbine. Its downwards movement opens the upper pilot valve so that more steam is admitted to the turbine under steady conditions the reverse happens for upward movement of speed changer. By adjusting the linkage position of point P the scheduled speed/frequency can be obtained at the given loading condition.

84. Schematic of speed governing system

85. TWO AREA LOAD FREQUENCY CONTROL Modern day power systems are divided into various areas. For example in India, there are five regional grids, e.g., Eastern Region, Western Region etc. Each of these areas is generally interconnected to its neighboring areas. The transmission lines that connect an area to its neighboring area are called tie-lines. Power sharing between two areas occurs through these tie-lines. Load frequency control, as the name signifies, regulates the power flow between different areas while holding the frequency constant. As we have an Example 1 that the system frequency rises when the load decreases if ΔPref is kept at zero. Similarly the frequency may drop if the load increases. However it is desirable to maintain the frequency constant such that Δf =0. The power flow through different tie-lines are scheduled - for example, area- i may export a pre-specified amount of power to area- j while importing another pre-specified amount of power from area- k . However it is expected that to fulfill this obligation, area- i absorbs its own load change, i.e., increase generation to supply extra load in the area or decrease generation when the load demand in the area has reduced. While doing this area- i must however maintain its obligation to areas j and k as far as importing and exporting power is concerned. A conceptual diagram of the interconnected areas is shown in Fig below

86. Interconnected areas in power system The load frequency control (LFC) has the following two objectives: 1.Hold the frequency constant ( Δf = 0) against any load change. Each area must contribute to absorb any load change such that frequency does not deviate. 2.Each area must maintain the tie-line power flow to its pre-specified value

87. THANK YOU ALL