EXAMPLE OF MODERN ACCELERATED RELAY PROTECTION ON A NINE-BUS POWER SYSTEM

Abstract. This paper proposes for consideration an example of modern advanced relay protection on a complex energy system.

Keywords: power system, electric power industry, relay protection, relay coordination, protection reliability, power grids.

The proposed algorithm for accelerated coordination is tested on a complicated interdependent nine-bus system with 24 overcurrent direction relays (Fig.) [6, p. 272], which make it necessary to optimize twice as many variables – 48 [3, p. 186]. In the event of a fault on the third line, the fifth and sixth relays isolate it from the serviceable part of the network, but, in the event that the sixth relay fails, after 0.2 seconds the task of providing protection shifts to the adjacent reserve twenty-third and eighth relays, according to their classification into left and right side groups as described [4, p. 95]. Within this division, for the main relay 1, its neighboring backup relays will be relays 15 and 17, and the backup relay for the main relay 1 will be relay 4, etc. [1, p. 7].

Figure. System with a 100 MVA, 33 kV – source

Then it is possible to find the values of the maximum short-circuit current. In the same system under study, the accelerated coordination method is compared not only with the particle swarm algorithm, but also with the genetic algorithm [2, p. 51]. The latter two algorithms took the same amount of time to optimize, about 33 seconds, while the proposed method performed the calculation of the best time and plug setpoints in less than 17 seconds, which represents the effectiveness of the advanced mathematical model for accelerated coordination of power system relay protection [5, p. 6].