Series Compensation Technology To Improve The Transmission Capacity Of The Yunnan Power Grid

During the project of Yunnan "12th five years" power grid planning, the hydropower in Yunnan got the large-scale development. The Northwest area in Yunnan is a place with quantities of developed water resources and little load, so most electric power in that area has to send out. However, the existing foreign sending channel cannot meet the sending requirements, the new transmission construction to exchange transmission line is very difficult and the construction of HVDC transmission lines is also uncertain. This will cause that power grid construction cannot keep pace with the large-scale development of hydropower. A large amount of power cannot send out. How to use the limited resources to deliver more power, become the urgent that need to address the problem.Series compensation technology adds capacitive reactance to offset the line inductive reactance in transmission lines. Therefore, the electrical distance decreases and the relationship of the power grid is strengthened. The TCSC devices not only short the transmission distance by electrical and improve network transmission capability but also through to the adjustment of the controlled system to damped vibration. In the insufficient damping dynamic areas the TCSC have obvious effect. The TCSC can greatly improve the level of high power grid stability.This paper elaborates the importance and development background of the series compensation capacitor, introduces the application at home and abroad, and descripts the details of the series compensation for the working principle, damping characteristics and calculation model. The control system and the effectiveness of the input signal of TCSC are analyzed. The simulation results of Yunnan power grid show that:the TCSC effect is good when section of the active power as TCSC input signal. Principle that series compensation improves the transmission capacity is analyzed and is simulated in the power system. The results show that:the FSC and TCSC can well improve the power grid Transfer Capability. TCSC is used primarily to raise the damping system and to improve the power grid transmission capacity.This paper is based on Yunnan "12th five years " power grid planning data, the Yunnan power grid to the outside limit, northwest Yunnan500kV section to the limit and220kV section to limit the are calculated. The results show that:Northwest Yunnan section transmission ability of foreign sending can not meet the demand, and the section of220kV line to limit is confined mainly by the heat stable limit and the section of220kV line to limit mainly is confined by the dynamic stability limit. In Northwest Yunnan power grid, the problem of limited section puts forward to the following project:In Northwest Yunnan500kV lines fixed series compensation is installed to improve extreme value of500kV section transport and in Northwest Yunnan220kV lines TCSC is installed to improve220kV foreign sending sections of transmitting limit. The project verified with simulation and the results show that the project can improve greatly extreme value of section transport.