Coordination of the transmission control center management and distribution control center management for disturbances in the regional parts of power system

Abstract

On the territory of the Republic of Croatia there is one transmission system operator and one distribution system operator. There is one national transmission control center and four regional control centers. The regional transmission control center for the Slavonia area cooperates with five distribution control centers.Distribution area of Elektroslavonija Osijek has had two significant disturbances caused by the transmission network in the last four years, which reflected on the users of the distribution network.The last operation event of 25/07/2017. occurred due to thunderous storms and atmospheric discharge in TS 400/110 kV Ernestinovo. The result is the activity of busbar protection in TS 400/110 kV of Ernestinovo and the extreme voltage fluctation in the system. In the establishment of power system stability, a series of omissions occurred which will be explained in detail in the paper.The load shedding of the distribution part of the system was more than 50%.Apart from difficulties in communication between control centers, the mentioned operation events have indicated the impact of the distribution power plants, that is, an additional stroke on the endangered part of the power system.Since disturbances of this type are rare and sporadic, it is necessary to use them for analyzes from which will result the rules of action for all participants in crisis situations.Based on previous experience make a proposal for "Rules for Coordinating System Operators in Procedures of Re-establishment of Power Supply" and these rules should be approved by the regulator.