Study On Unified Peak Modulation Of Hydro-thermal Power Plants In Hainan Power Grid

At present, the hydro-thermal co-operation in general is to make hydropower system shave the peak load, and the remaining is contributed by thermal power units. When the hydro peaking capacity is inadequate; or in the flood season, it have to reduce surplus water of reservoir, thermal power unit should bear the peaking operation. Hydro-thermal co-peaking is to undertake a study for peak solving; it has certain practical engineering significance.That thermal power take part in peak shaving will encounter difficulties: First, thermal power units are constraint by unit ramp rate; second is to contribute to demand as smooth as possible. The current practice is to divide the load into three paragraphs, or multi-segment under the control of thermal unit ramp rate, in this range of load thermal unit output is smooth. The remaining is due to hydropower to balance. If the hydropower capacity is inadequate, this approach is not suitable. So it is need to find a solution to assist thermal unit climbing, this paper presents a cut-paste method to assist in the thermal power climbing, and shall apply to the smaller proportion of hydro-power generation scheduling in Hainan. The main work of this paper is as follows: 1) Comparison of power system load balance on a variety of ways, summarize two major issues in the hydro-thermal co-peaking - the thermal unit ramp rate and contribute to a smooth climbing demand.2) This paper proposes a method which hydropower cut peak load to make up part of the vacancy of thermal power units. The method sets thermal output keeping a minimum duration.3) The little proportion of hydropower in Hainan Province needs to hydro-thermal co-peaking, co-scheduling hydro-thermal method is used in the Hainan Power Grid daily generating plan. In the energy-saving mode, peak load and base load is divided into two blocks for distribution. Peak load is allocated by the method mentioned above cut-paste; base load is allocated by the thermal unit accordance with the rate of coal-consumption by coal-fire units. In this mode, it is received by daily load distribution plan to meet the power unit power balance, on the other hand has also made energy-saving emission reduction results.