考虑电网运行可靠性的大用户接入投资决策方法

A Large User Access Investment Decision-making Method Considering the Reliability of Power Grid Operation

新型电力系统的建设是实现“双碳”目标的重要手段,具有强随机性、波动性、间歇性的大量新能源接入,使得未来电力系统的安全稳定运行面临严峻的挑战。而符合地区地位优势,促进经济发展的大用户,通常具有负荷特性复杂、供电可靠性高等特点,为减少大用户落户受电网稳定运行等制约因素的影响,提出将大用户和电网作为整体,在DigSILENT/PowerFactory仿真软件建立大用户变电站与上游电网联络线、站内母线、主变、保护装置等的三态马尔科夫故障模型,设置相应的可靠性参数,提出负荷点每年的故障频率、故障持续时间、平均供电可用度三个可靠性评估指标。针对某沿海城市某大型用户供电拟定不同接入电网方案,对大型用户投产当年及五年后的方案可靠性指标进行评估。结果表明,基于三态马尔科夫故障模型仿真结果的可靠性指标评估能够为电网公司进行大用户接入电力系统方案决策提供技术性支持。

The construction of new power system is an important means to achieve the goals of“carbon emission peak and carbon neutrality”,and a large number of new energy access with strong randomness,volatility and intermittently makes the safe and stable operation of the future power system face severe challenges.In line with regional status advantages and promoting economic development,large users usually have complex load characteristics and high power supply reliability.In order to reduce the influence of large users’settlement on the stable operation of the power grid and other constraints,taking large users and the power grid as a whole was proposed.In the DigSILENT/PowerFactory simulation software,a three-state Markov fault model was established between the large-user substation and the upstream power grid contact line,the bus bar in the station,the main transformer,the protection device,etc.,and the corresponding reliability parameters were set.Three reliability evaluation indexes were proposed,which were annual failure frequency,annual failure duration and average power supply availability.For a large user in a coastal city,different grid access schemes are proposed,and the reliability indexes of the schemes are evaluated in the year of operation and five years after the large-scale user is put into operation.The results show that the reliability index evaluation based on the simulation results of the three-state Markov fault model can provide technical support for the power grid company to make decisions on the schemes of large user access to the power system.