Analysis of Northern Region Electricity Board (NREB) Grid Disturbance

Abstract

The Northern Regional Electricity Board (NREB) consists of generating and transmission power utilities of the states UP, Rajasthan, J&K, Punjab, Himachal Pradesh, Haryana, and the central utilities viz Powergrid, NTPC, NPC, BBMB, DVB etc. NREB is the largest regional electricity board. The NREB grid experienced several major grid disturbances in the recent past resulting in cascade tripping of 400 kV lines and generating units. This resulted in separation of grid into several isolated parts with disruption of power supply. On certain occasions several EHV lines tripped leading to total blackout. This paper deals with the analysis of the grid disturbance that occurred on 26th Nov’96. In this paper main emphasis is given to superimpose dynamic variation of characteristic impedance on relay characteristics. The effectiveness of Power System Stabilizer (PSS) to avoid/minimize such grid disturbances is attempted.