Evaluation of Measures for Improving the HPP Generating Equipment Transient Stability Conditions

One of the basic principles of managing the electric power system operation modes is to ensure the synchronous transient stability of electric power plant generating equipment. Given the rapidly growing power consumption in Russia, a growth in the number of regional power systems with a shortage of generating capacities is observed. At the same time, there is a number of power systems the available generating capacity of which is sufficient to compensate for the shortage of power in other pools. The problem that has to be dealt with under such conditions is a limited transmission capacity of existing networks, the development of which is necessary to secure reliable power supply for consumers. The Sayano-Shushenskaya hydroelectric power plant (HPP), which is Russia’s largest power plant, supplies power to the Unified Energy System via long high-capacity transmission lines. In a number of operating modes (without taking into account the emergency control arrangements), the Sayano-Shushenskaya HPP has limitations on the output power from the considerations of power system transient stability under the conditions of disturbances specified by the relevant regulatory documents. Electromechanical transients were calculated, and the most severe design-basis disturbance was determined. Technical methods and means to ensure the HPP generating equipment synchronous transient stability under the conditions of the most severe design-basis disturbance are considered. The methods and means considered include the use of a series capacitive compensation device in the Sayano-Shushenskaya HPP – 500 kV Novokuznetsk substation line (the line inductive reactance compensation degree is 50 %) and the implementation of automatic unloading functions at the HPP in case of short circuit faults in the 500 kV backbone grid as part of the emergency control system producing commands to trip the HPP units.