Study on Measures to Improve the PV Hosting Capacity of Tibet Power Grid

Abstract

Measures to improve the solar PV hosting capacity of Tibet power grid are studied. The industrial foundation of Tibet autonomous region is less developed, its load level is rather low, the power grid structure is relatively weak, and the power source mainly includes hydropower and photovoltaic, the peak regulating capacity is very limited. Therefore, its PV hosting capacity is inadequate and solar light discard rate is somewhat high (more than 30 percent often). How to improve the PV hosting capacity of Tibet power grid is an urgent problem. The main characteristics of Tibet power grid include: large capacity generator within small power system, strong DC coexists with weak AC, grid structure is rather weak. Most of the power sources in Tibet are hydropower. The proportion of PV installed is large, and the proportion of thermal power is very small and only used for peak load regulation, and they are cold standby generators. The daily peak load in Tibet appears at night, and the yearly maximum load is in winter. Therefore, Tibet power grid needs a lot of incoming power in winter while the solar light discard rate is rather high in summer. In normal operation mode, the PV outputs are limited seriously, but the capability of PV power generation to participate in frequency adjustment, to support the transient stability and voltage stability of the power grid has not been developed. According to the characteristics of Tibet power grid, three measures to improve the PV hosting capacity of Tibet power grid are studied, includes:1)Improving the active power control of the PV power station.2)Realizing globally reactive power optimized coordination control by coordinated control of reactive power compensation equipment.3)Improving the generator-grid coordination performance by changing the related parameter settings. Related control models are built, the simulation calculations results show that the above three kinds of measures can effectively improve the PV hosting capacity of Tibet power grid, the three measures have their application value respectively and can be used in combination.