省级异步电网频率强度在线评估方法及应用

Online Evaluation Method and Application of Frequency Strength of Provincial Asynchronous Power Grid

电力系统分区异步互联、大规模新能源替代传统同步机使得系统频率强度降低,频率失稳风险增加。此时,在线评估系统频率强度、监测系统频率稳定裕度对系统安全稳定运行具有重要意义。为此,提出了适用于实际省级异步电网的频率强度在线评估方法,包括数据获取与预处理、系统调频模型简化以及系统频率强度评估三个部分。首先,基于运行控制系统获取各设备开机、出力情况等工况信息,并通过BPA数据以及广域测量系统中的数据建立系统中设备调频动态模型库。其次,通过统一结构近似的方法将设备模型进行降阶,进而计算频率跌落深度系数以及坡度系数等指标以评估系统频率强度。最后,介绍了基于所提评估方法研发的频率强度在线评估系统及其在实际电网中的应用情况。

The partition asynchronous interconnection of power systems and the replacement of traditional synchronous machines by large-scale new energy sources reduce the frequency strength of the power system and increase the risk of frequency instability.At this time,online evaluation of system frequency strength and monitoring system frequency stability margin are of great significance to the safe and stable operation of the system.Therefore,an online evaluation method of frequency strength suitable for the actual provincial asynchronous power grid is proposed,including three parts:data acquisition and preprocessing,simplification of system frequency modulation model and system frequency strength evaluation.Firstly,based on the operation control system,the operating condition information such as the startup and output of each device in the system is obtained,and the dynamic model library of the frequency regulation of devices in the system is established through the BPA data and data in the wide area measurement system.Secondly,the order of device model is reduced by the unified structural approximation method,then the frequency strength indexes such as frequency drop depth coefficient and slope coefficient are calculated to evaluate the system frequency strength.Finally,the developed frequency strength online evaluation system based on the proposed evaluation method and its application in the actual power grid are introduced.