转动惯量对西藏林芝电网外送能力影响机制分析

Analysis on Influence Mechanism of Rotational Inertia Level of Generators at Sending End on Outward Power Transmission Capability for Linzi Power Network Connected With Tibet Power Grid

增加电网输电能力是提高一次能源利用效率、增大电网安全稳定裕度和提升电网整体运营效率的有效途径。在电网建设初期和过渡期,由于技术经济性、工程建设进度、季节性发电能力差异等因素影响,通常存在电源外送容量受限于电网输电能力的情况。首先基于等面积定则原理,分析了送端电网发电机转动惯量对故障期间转子加速能量积聚,以及故障清除后电网所能提供最大减速能量的影响,揭示了增加转动惯量提高输电能力的机制。在此基础上,研究了西藏林芝外送型电网中老虎嘴主力电源开机方式,对联络线受扰轨迹和外送能力的影响,指出林芝与藏中主网单回线弱互联条件下,优化开机方式增加林芝电网转动惯量,是提高外送能力和安全稳定裕度的有效技术措施。

Increasing transmission capability of power grid is an effective approach for improving utilization efficiency of primary energy source, enhancing security and stability margin of power grid and lifting overall operational efficiency of power grid. During the initial period and the transitional period of power grid construction, in view of the impacts of techno-economy, implementation scheduling of the project, difference of seasonal power generation capacities, the circumstance that the outward transmission capability of power source is restricted by transmitting capacity of power grid exists in general. Firstly, based on equal area criterion, the influences of rotational inertia level of generators at sending end on both accelerating energy accumulation of rotors during fault period and the maximum decelerating energy that power grid could provide after cleaning up the fault are analyzed, and the mechanism of enhancing outward power transmission capacity by increasing rotational inertia of generators is revealed. On this basis, the impacts of generation scheduling of Laohuzui main power plant in Tibet＇s Linzi power network that transmits power outwards on disturbed trajectory of tie line and outward transmission capability are researched, and it is pointed out that under the weak interconnection of Linzi power network with Tibet power grid via single circuit transmission line, the optimization of increasing rotational inertial by optimizing generation scheduling is an effective technical measure to improve outward power transmission capability andenhance security and stability margin.