DISTURBANCE MANAGEMENT IN THE TURKISH POWER SYSTEM INTERCONNECTED WITH THE ENTSO-E SYSTEM - DEFENCE STRATEGIES AND OPERATION EXPERIENCE

摘要

The main scope of the paper is to describe the innovative System Integrity Protection Schemes (SIPSs) in operation in the Turkish Electric Power System (EPS), that dating from September 2010 is synchronously connected to the ENTSO-E/CESA system (European Network of Transmission System Operators for Electricity-Continental Europe Synchronous Area). The long longitudinal configuration of the transmission system from Western Europe to Turkey through the Balkan countries has required many studies and technical adaptations of the Turkish EPS to the ENTSO-E regulations, including a defence plan for ensuring the angular and voltage stability of the interconnected operation, for minimizing the risk of system separation, for drastically reducing the propagation to the neighboring countries of the disturbances which may occur in Turkey, and damping the inter-area oscillations. Analyses had shown [1] that the disturbances to be countered for complying with the above listed requirements are the large sudden load/generation imbalances that may occur in Turkey. After an overview of the present status of the Turkish EPS, the paper describes the functions, specification, settings and operation experience of three SIPS in operation in Turkey. The 1st SIPS has been in operation since 2010 and is installed in the interface between the 400kV grids of Turkey and of Bulgaria-Greece. This SIPS is response-based. It detects the sudden load/generation imbalances that may occur anywhere in the system, by means of the measurement of electrical quantities in the interconnection transmission lines (TLs), which allow the fast on line calculation of two dynamic indicators of the size and sign of the imbalances. The paper then describes two SIPSs, that are in operation dating from 2014, one in the Southern Marmara Sea region and the other in the Eastern Black Sea region of Turkey. Installation has been justified because of a large fast increase of generation in these regions and delays of construction of the necessary new TLs for power transmission to remotely located load centers. This has caused the temporary regional non-compliance with the (N-1) security criterion. A 400kV TL outage can therefore cause a regional blackout, with large loss of generation in the national EPS and also intervention of the SIPS in service in the interface with the ENTSO-E system. The paper reports the identification of the disturbance indicators for the response-based actions and of the allowed very short time for putting in effect the corrective measures by each of these SIPSs. A chapter of the paper gives brief information on the other disturbance management countermeasures, in particular: the automatic under-frequency load shedding; the allowed ranges of frequency operation of the generators; the Summer automatic undervoltage load shedding in the South-Eastern region; an innovative solution for damping the low-frequency inter area oscillations; the protection system of the 400kV grid; the Phase Measurements Units (PMUs); the system restoration after a blackout.