Analysis on the Influence of Rotational Inertia Level of Sending System on Transmission Capability

It is an effective approach to improve utilization efficiency of primary energy source, to enhance security and stability margin of power grid and to lift overall operational efficiency of power grid via increasing transmission capability 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, generally, there exists a circumstance that the outward transmission capability of power source is restricted by transmitting capacity of power grid. At first, it is analyzed that 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 provide by power grid after cleaning up the fault, which is based on equal area criterion, and the mechanism of enhancing outward power transmission capacity by increasing rotational inertia of generators is revealed. On this basis, it is researched that the impacts of generation scheduling of Laohuzui main power plant in Tibet's Nyingchi power network which transmits power outwards on disturbed trajectory of tie line and outward transmission capability, and it is pointed out that with the weak interconnection of Nyingchi power network with Tibet power grid via single circuit transmission line, it is an effective technical measure to improve outward power transmission capability and enhance security and stability margin by optimizing generation scheduling and increasing rotational inertial.