OPTIMIZING RESERVOIR DRAWDOWN BY COMPENSATING FOR REACTIVE POWER: THE CASE OF THE ZEYA HYDROELECTRIC

Abstract

This article examines the problem of optimizing the water and energy regime of the Zeya Hydroelectric Power Plant, which is associated with the need to use hydrogenerators to compensate for reactive power during periods of minimal active load. This regime leads to excessive water consumption, increases the risk of generator outages due to operation in the under-excitation zone, and is economically inefficient. The objective of this study is to improve the efficiency of the Zeya Hydroelectric Power Plant’s reservoir drawdown regime by developing and conducting a feasibility study for a method for compensating reactive power directly at the plant’s busbars. Based on an analysis of the circuit and operating modes of the grid connected to the Hydroelectric Power Plant, two solution options are considered: increasing the voltage at the plant’s busbars and installing of a 500 kV controlled shunt reactor. Modeling confirmed that the controlled shunt reactor option completely eliminates excess charging power from long transmission lines, maintains voltage within acceptable limits, and prevents hydrogenerators from operating in under-excitation mode. This ensures that only two required hydroelectric units can operate during the night minimum, which is essential for optimizing reservoir drawdown.