a study on human pulse monitoring device.pptx

presntation about thesis

1. WELCOME TO THE PRESENTATION

2. Operation and Maintenance of 33/11 KV Tongi (Central) Sub-Station DESCO Saiful Islam ID- 1 9205009 Department- BSEEE Presented By : Supervised By : Dr. Md. Rukonuzzaman Associate Professor Department of Electrical and Electronic Engineering IUBAT-International University of Business Agriculture and Technology Presentation on

3. Contents Objectives Introduction Company Overview Knoledge and Skill Development Personal Development Challenges and Suggestion Substation Components Of Sub-Station Operation Of DESCO Power transformer Conclusion Reference

4. Objective To know about the operation of Dhaka Electric Supply Company Limited (DESCO). To know about the Power distribution procedure. To know about the operation and maintenance of substations. To know the repairing process of a transformer.

5. Introduction Electricity Supply means the supply of electrical energy by us, metering services by us through our metering services provider, and the provision of line services for the delivery of electricity by the lines company. Substation Operation and Maintenance is a comprehensive reference on operating and maintaining all the essential components of substations: power transformers, circuit breakers, capacitors,reactors, regulators, protective relays, control systems, and batteries.

6. Company Overview DESCO started its operational activity on September 24, 1998 by taking over of Mirpur area from DESA. License from BERC: 15 November 2006 . Initial activity of DESCO- Operation & Maintenance of Sub-Stations & Lines Commercial functions Planning, d esign, installation of Substations & lines, etc .

7. Company Overview (Cont..) Vision To contribute to the economic development and social progress of the country by providing safe, reliable, and sustainable electricity services. Contribute to building a strong nation by bringing customer comfort to life, assisting in business, providing better services to customers, and gaining customer confidence. Mission

8. During my internship at DESCO, I gained hands-on experience in switchgear and protective relay areas, including installation, testing, maintenance, and troubleshooting. I worked on components like ACR, voltage regulators, circuit breakers, and isolators. During my internship, I gained firsthand experience in analyzing electrical issues and system performance, identifying patterns in relay data, and understanding protective relay schemes to improve network reliability and operation under various failure situations. During my internship, I honed my communication skills by working closely with the substation team, ensuring timely completion of tasks and fostering effective teamwork. Knoledge and Skill Development

9. Open communication is crucial in the energy industry, as demonstrated by my internship at DESCO. It fosters trust and provides accurate information. Integrity, a moral principle, is essential in all aspects of the profession, from energy acquisition to client interactions. As an intern at DESCO, I learned about safety guidelines and policies, including adhering to work schedules and wearing PPE due to high voltage power. This experience taught me the importance of adhering to safety measures. Personal Development

10. During my internship with DESCO, I learned new skills but struggled with using their 33 kV underground lines and proprietary software, OSMSS, for new meter connections and bill approval. This experience highlighted the challenges I faced in using these tools. During my internship, I faced technical and operations challenges, such as lack of specialized equipment and hands-on training for switchgear and protective relay systems. To align with real-world applications, a learning environment with regular updates, access to tools, and collaboration between academic institutions and industry partners is needed. The department should mandate industrial tours for all major courses and establish connections with credible power-based businesses to enhance academic growth and benefit students and practicums. Challenges and Suggestion

11. Substation A place where voltage transfers from step-up to step-down or step-down to step-up. There has many protective devices for protecting the system from faulty conditions. In the electrical system power is managed from the substation. It should be located at a proper site. It should provide safe and reliable arrangements. It should be easily operated and maintained. It should involve minimum capital cost.

12. Substation (Cont..) Types of substations According to constructional features, the sub-stations are classified as: Indoor substation Outdoor substation Underground sub-station Pole-mounted substation

13. Substation (Cont..) Figure 2: Indoor substation For voltage below 66kV Due to low clearance requirements, indoor installment can be done. For voltages beyond 66 kV Indoor substation Due to high Voltage, more clearance requirements. Figure 3: Outdoor substation Outdoor substation

14. Substation (Cont..) Figure 4 : Underground substation Due to the high cost of land , Underground installment can be done. For voltages below 33 kV Underground substation This is an outdoor substation installed overhead on H-pole . Figure 5 : pole-mounted S ubstation Pole-mounted substation

15. Component of Substation The main component of substation are- Transformer Isolator Circuit breaker Bus-bar CT (Current transformer) PT (Potential transformer) Protractive Relay Insulator Lightning arrester Auxiliary transformer Battery and Battery Charger

16. Isolator Component of Substation (Cont..) Transformer AC to AC converter that changes the voltage level T ransfers the energy from one circuit to another circuit through the action of a magnetic field Figure 6 : 132/33 kV Grid Transformer Isolator A mechanical switch that isolates a part of a circuit from the system. Figure 7 : Isolator

17. Component of Substation (Cont..) Circuit breaker A n automatically operated electrical switch designed to protect an electrical circuit from damage caused by excess current from an overload or short circuit. Figure 8: SF 6 Gas Circuit Breaker Figure 9: Vacuum Circuit Breaker

18. Component of Substation (Cont..) CT (Current transformer) U sed for measuring and also for the protection U sed to transform the high current into the desired value of the current required in the circuit. The main function of the Potential transformer is to step down the voltage level to a safe limit or value. P T (Potential transformer) Figure 10: Current Transformer Figure 11: Potential transformer

19. Component of Substation (Cont..) Bus-bar C opper rods or thin-walled tubes and operate at a constant voltage. Collecting electric power from the incoming feeders and distributes them to the outgoing feeders. A device that detects the fault and initiates the operation of the circuit breaker to isolate the defective element from the rest of the system Protractive Relay Figure 12: Bus-bar Figure 13: Protective Relay

20. Component of Substation (Cont..) Insulator Insulator mainly use for insulation purposes to support and separate electrical conductor’s to support and separate electrical conductor’s without allowing current through themselves use for protecting the whole system from lightning because during lightning excessive charge is produce Lightning arrester Figure 14: Insulator Figure 15: Lightning arrester

21. Component of Substation (Cont..) Battery used to provide supply to the auxiliary equipment’s and substations own needed power T his transformer transforms 33 kV to 0.415 kV Auxiliary transformer Figure 16: Battery Figure 15: Auxiliary transformer R equired for protection, control and signaling. Battery supplies 110V dc voltage to ensure protection.

22. Single line Diagram of Tongi (Central) Substation

23. Power Distribution Table for one day at Tongi Central S & D Division Table 2.1: One Day Power Distribution Date: 28/11/2023 12:37:19

24. Calculation of Tongi (Central) Substation If we take 95% efficiency then ratings of each transformer will be 26.6 MVA . Total MVA = 3*26.6 MVA = 79 .8 MVA Maximum Load Capacity of this Substation: = Total MVA*Power Factor = 79.8 *0.9 = 71.82 MW Calculation of Maximum Load Capacity

25. Operation of DESCO Sales and Distribution consist of two functions: Commercial operation. Systems Operation Commercial Operation Disconnection / Reconnection – Metering One-point service center Billing /collection

26. Operation of DESCO (Cont..) System Operation New connection Load sanction & load retention Load management Control room activity Power factor monitoring & upgrading Substation operation & maintenance Line maintenance

27. Operation of DESCO (Cont..) New connection Consumers need to give an application online with some documents. DESCO verified this document and give the approval based on load. Load sanction and load retention Small amount of load taken from the source line is load sanction . Allocated load taken from the source line is load retention.

28. Operation of DESCO (Cont..) Load Management Also known as demand side management . Balancing the supply with the electrical load by controlling the load. Control room activity The main work of control room is distributing the load / management the load . Balance the Allocated load and demand load by plan load shedding . Keep note of the maximum load and minimum load . Register the shut-down data with reason and shut-down time.

29. Operation of DESCO (Cont..) Reason of shut-down Power factor monitoring and Upgrading Break down Line maintenance Line extension Substation maintenance Plan load shedding DESCO monitoring the power factor every week and improve the as soon as possible.

30. Operation of DESCO (Cont..) Benefits Of Power Factor Correction Reduced Demand Charges Increased Load Carrying Capabilities in Existing Circuits Improved Voltage Reduced Power System Losses Reduced Carbon Footprint

31. Operation of DESCO (Cont..) Substation maintenance A substation can’t give its best output severe without maintenance Maintenance means checked all the equipment performance Maintenance of Bus bars Check insulator supports, clean if necessary. Bus-bur contact resistance check Check the physical condition of bus. Maintenance of potential transformer Check all screwed joints and contact for a tight fit . Check insulating if necessary .

32. Operation of DESCO (Cont..) Maintenance of Current Transformer Check all screwed joints and contact for tight fit. Check insulation if necessary, when an excessive amount of dirt has accumulated. Check primary/secondary connectors and conduct necessary tightening. Maintenance of Lightning Arrester Visual inspection & check of all wiring connectors. Check insulator and metal circular ring, clean. Check the physical condition of Lightning Arrester.

33. Operation of DESCO (Cont..) Maintenance of Transformer Check the Buchholz relay function completely. Check the transformer Marshalling box. Transformer insulation resistance test. Transformer earthing test. Transformer oil completely check. Transformer body clear and paintwork. All power and control terminal tightness and overheating check

34. Operation of DESCO (Cont..) Maintenance of Circuit Breaker Contact resistance Check Insulation check Gas pressure check. Give contact gris in the contact part. Emergency maintenance is required when any uncertain hazard is occurred in the substation.

35. Transformer Repairing Center Component of Power Transformer Transformer Main Tank Winding Core Insulation Transformer oil Conservator Tank Bushings Radiators Buchholz Relay Breather Tap Changer

36. Transformer Repairing Center Repair procedure of a 3-Phase out of order Transformer

37. Transformer Repairing Center Reasons for Transformer Failures Unbalance load conditions. Continuous overloading of transformer beyond rated capacity High operating temperature Improper earthing connection O il Problem Lightning or Line Surges Transformer main tank leak

38. Conclusion DESCO is one of the best practical grounds for Electrical and Electronic Engineers in our country . I have learned a lot and obtained practical knowledge during my internship that I learned in theories. I have learned about the design, implementation, operation, and maintenance of a distribution substation. It has increased my confidence level for facing job interviews in the future.

39. Recommendation Internship Program Time should be increase for DESCO. They should replace the new transformer instead of the old transformer . They should install solar panels in their head office as well as their (S&D) offices.

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