高比例可再生能源电网功率平衡的实时调度临界时间尺度研究

On the Critical Timescale of Real-time Dispatch Considering Power Balancing Under Power Systems With High Proportional Intermittent Power Sources

为了有效发挥实时调度的功率平衡作用,须明晰高比例可再生能源电网实时调度环节应遵守的功率平衡约束,须以功率平衡约束为前提确定实时调度时间尺度。实时调度功率平衡功能的两个约束条件:功率消纳能力以短期调度确定的消纳备用为约束;实时调度时间尺度以自动发电控制(automatic generation control,AGC)的功率调节范围为约束。基于递进衔接的调度控制体系,采用不确定度函数描述间歇式电源发电功率不确定性统计规律,进而提出了高比例可再生能源电网实时调度临界时间尺度的解析公式。解析式给出了实时调度临界时间尺度与间歇式电源功率不确定性、运行占比和AGC功率调节范围三个因素的函数关系,解决了高比例可再生能源电网实时调度时间尺度的量化选取问题。分析和数值计算表明,任何高比例可再生能源电网都对应一个与之适应的实时调度临界时间尺度,都能有效地实现电网的功率平衡目标。

To address the side effects of intermittent power uncertainty towards power balancing, real-time dispatch must participate into the power balancing of high proportional renewable energy systems. To participate into power balancing, real-time dispatch must satisfy two conditions of constraints: first, take the accommodation reserve from short-term scheduling as one constraint to balance the power imbalance caused by short-term power forecasting; second, take the power balancing capability of AGC as another constraint to properly set up the timescale of real-time dispatch. Based on the dispatching control system, this paper applied the statistical forecast functions which describe the forecast uncertainty of intermittent power sources, and proposes an analytical formulation which describes the relationship of critical timescale for real-time dispatch with factors such as the amplitude and time constant of the uncertain function and the operational proportion of intermittent power sources. This analytical formulation has provided theoretical evidence on ascertaining the real-time dispatch timescale from the perspective of power balancing. The power balancing can be achieved as long as the real-time dispatch timescale is less than the critical real-time dispatch.