Developing wide area phase plane primary protection scheme “WA4PS” for complex smart grid system

Abstract

The paper presents a new wide area phase plane primary protection scheme “WA4PS” for interconnected electric bulk power system protection. The main purpose is to get a decision based on data sharing instead of the traditional primary stand alone relays. The principle of protection depends on getting autonomous plane solution for the differential equations of the transmission line with constant coefficients. The differential equations that describe the transmission line contain complex eigen values and the paths of the phase plane should be ellipse. The phase paths of solving this autonomous plane system depend on the eigen values changes according to the different types of faults on the transmission line. The fault pattern of a particular solution in the phaseplane called the trajectory of the solution. The trajectory of the solution can easily identify the faulted line based on the equilibrium solution as tincreases. The new idea depends on data collected from different phasor measurement units “PMUs” deployed on a real interconnected 500/200kV grid. The faults on the transmission line can be accurately identified in a time estimated by 5msec and with a latency in the communication by 50msec based on 4G technology. This reason refers to consider the WA4PS as a primary protection.