Influences on CPS frequency evaluation indexes after large scale wind power joining up to East China power grid

摘要

Influenced by the energy crisis and environmental stress, wind power is growing rapidly for its mature technology and good economic returns. East China Power Grid is planning to construct million kW level wind power base in northern Jiangsu coastal areas. As one kind of intermittent energy, wind power's output changes as wind speed. When wind power is in a small proportion of total power generation, unbalance energy caused by wind power's fluctuations usually can be illustrated in Jiangsu power grid. At that time, the power and frequency deviation of connection lines is small and only brings little effects to ACE, which will not cause CPS1 and CPS2 assessment index inadequate. But when wind power capacity reaches a certain proportion, only relying on the regulation of AGC ability of Jiangsu generators cannot recover power balance in time, and more conventional units reserve is required. In order to keep ACE in a rational range, artificial adjustment by dispatchers is the only choice. Due to the fact that the speed of artificial adjustment cannot follow wind power output change, it may cause CPS assessment index unqualified. This paper amends formula of ACE calculation considering wind power output fluctuations. Although wind power is still dispatched by Jiangsu power dispatching center, this paper separates wind power from East China power dispatching region virtually, and establishes a virtual line between wind power and Jiangsu region. In the future by 2020, wind power capacity installed at Jiangsu grid will reach to 10 million kW, the contradictions between assuming responsibilities and getting benefits brought by consuming abundant wind power will be more apparent at the same time, so some reasonable arrangement should be made ahead. This paper also presents some corresponding suggestions.