Lecture 9c - Wave Trap.pptx

Wave Trap

1. Dr. Ahmad Al- Subhi Prepared by: Dr. Ahmad Al- Subhi SWITCHGEAR AND PROTECTION Lecture 9 OTHER SWITCHGEAR COMPONENTS

2. Prepared by: Dr. Ahmad Al- Subhi 9a. Isolator. 9b. Surge Arrester. 9c. Wave Trap. 9d. ATS and UPS. Outline:

3. Dr. Ahmad Al- Subhi Prepared by: Dr. Ahmad Al- Subhi SWITCHGEAR AND PROTECTION Lecture 9c WAVE TRAP

4. Prepared by: Dr. Ahmad Al- Subhi Basically, there are two signals in the line: Power signal (in Hz). Communication signal (in kHz- MHz range). Carrier wave communication uses up to 150 kHz to 800 kHz frequency to send all the communication. These high frequencies can damage the power system components which are designed to operate at 50 or 60 Hz. Wave trap (called also a line trap) is a LPF (low pass filter) which allows the 60 Hz power signal to pass through it and blocks the high- frequency carrier signal from entering the power substation.

5. Prepared by: Dr. Ahmad Al- Subhi

6. - Wave trap is connected in series with the transmission line. - However, this causes resonance with capacitors like line capacitors, capacitive voltage transformer capacitor …etc. - Inductive reactance: X L = 2π f L Prepared by: Dr. Ahmad Al- Subhi

7. To solve this, inductance is shunted by a tuning capacitor in order to tune the line trap to the desired blocking frequency. It provides a high impedance to carrier frequencies and low impedance path for the power frequency . Prepared by: Dr. Ahmad Al- Subhi

8. Currently, PLCs are replaced by OPGW ( Op tical G round W ire). OPGW acts as normal ground wire protecting phase wires from lightning strikes and carries earth fault current. Apart from its application as an earth wire, OPGW also provides an optical path in power line installations for communication & protection needs. OPGW eliminates the coupling capacitor & wave trap thereby reducing the system complexity and enhancing the reliability. Lecture 9d: ATS and UPS Prepared by: Dr. Ahmad Al- Subhi