LAB2.docx - POWER SYSTEM PROTECTION SWITCHGEAR LAB ASSIGNMENT 02 SURABHI RAMAN 17BEE0029 MICRO-CONTROLLER BASED OVER\/UNDER VOLTAGE RELAY IDMT\/DMT RELAY

LAB2.docx - POWER SYSTEM PROTECTION SWITCHGEAR LAB...

This preview shows page 1 - 4 out of 10 pages.

POWER SYSTEM PROTECTION & SWITCHGEAR LAB ASSIGNMENT - 02 SURABHI RAMAN 17BEE0029
Image of page 1
MICRO-CONTROLLER BASED OVER/UNDER VOLTAGE RELAY IDMT/DMT RELAY Ex.No : 02 AIM i. To study the Micro Controller based over voltage relay. ii. To study the Micro Controller based Under Voltage relay. EQUIPMENT REQUIRED 1) VPL – 05 Module 2) 1 φ Auto transformer 3) Connecting wires Formulae Used: 1. Calculate Relay tripping time for over voltage IDMT Relay t = TMS [ K [ V V S ] α 1 ] + C 2. Calculate Relay tripping time for Under voltage IDMT Relay t = TMS [ K [ V S V ] α 1 ] + C α = 0.02, K = 0.14, C = 0 Theory In a power system consisting of generators, transformers, transmission and distribution circuits, it is inevitable that some failure will occur somewhere in the system. When a failure occurs on any part of the system, it must be quickly detected and disconnected from the system. There are two principle reasons for it. Firstly, if the fault is not cleared quickly, it may cause unnecessary interruption of service to the customers. Secondly, rapid disconnection of faulted apparatus limits the amount
Image of page 2
of damage to it and prevents the effects of fault from spreading into the system. The detection of a fault and disconnection of a faulty section or apparatus can be achieved by using fuses or relays in conjunction with circuit breakers. A fuse performs both detection and interruption functions automatically but its use is limited for the protection of low-voltage circuits only. For high voltage circuits, relays and circuit breakers are employed to serve the desired function of automatic protective gear. The relays detect the fault and supply information to the circuit breaker which performs the function of circuit interruption. A Protective relay is a device that detects the fault and initiates the operation of the circuit breaker to isolate the defective element from the reset system. The relays detect the abnormal conditions in the electrical circuits by constantly measuring the electrical quantities which are different under normal and fault conditions. The electrical quantities which my change under fault conditions are voltage, current, frequency and phase angle.
Image of page 3
Image of page 4

You've reached the end of your free preview.

Want to read all 10 pages?

  • Winter '17
  • DD
  • Relay

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture