System Strength Enhancement with Synchronous Condensers for Power Systems with High Penetration of Renewable Energy Generators

The number of synchronous generators is anticipated to be reduced in the future power systems. Factors such as favorable government policies and market's preference are driving enormous deployment of renewables, while there is very little interest in replacing coal fired power stations by the same type of power generators. These have culminated in the increased deployment of asynchronous generators in power systems. While these types of generators are environmentally friendly, they perform poorly in maintaining power system strength. This paper investigates the impact of photovoltaic (PV) generator on fault level as an indicator of system strength of a network. Various technological options for system strength improvement are discussed. It shows that system fault level can be supported by independent control of synchronous condenser's voltage and reactive power control. The paper also formulates an analytical control approach and demonstrates its suitability on a modified 35-bus utility system.