Transient Voltage Control of Sending-End Wind Farm Using a Synchronous Condenser Under Commutation Failure of HVDC Transmission System

Abstract

When the large-scale wind power is sent out through the high voltage direct current (HVDC) transmission system and a DC commutation failure occurs, the voltage of AC bus at the sending end decreases first and then increases. Suppose the reactive power supported in the low voltage ride-through process by various reactive resources is not timely returned. In that case, it may aggravate the voltage rise caused by the commutation failure, and the off-grid risk of wind turbine under high-voltage will be aggravated. In order to reduce the off-grid risk of wind turbines caused by the DC commutation failure, a transient voltage control strategy of DC sending-end regulator based on the online sequential extreme learning machine (OS-ELM) voltage prediction model is proposed. Firstly, the influence factors of commutation failures are analyzed. Aiming at the key factors, the real-time voltage comprehensive prediction model based on OS-ELM is used to predict the voltage increase during the commutation failure process and uses the voltage prediction results to optimize the transient response of the synchronous condenser. A large-scale wind farm together with the HVDC system is established in PSCAD to verify the effectiveness of the proposed scheme. Simulation results show that the proposed scheme can reduce the risk of wind power off-grid risk under DC commutation failures and increase the speed of voltage recovery at the point of common coupling. INDEX TERMSDC commutation failure; high voltage ride through; doubly-fed induction generator; synchronous condenser; transient voltage control

Rotor Angle Stability Analysis and Enhancement of Synchronous Condenser in Large-Scale Renewable Energy Farms

“…According to ( 4) and (7), the system has equilibrium points when Peqe= Pmeq, and ωsc=ωg, which leads to…”

“…Since the δsc and ωsc can be regarded as state variables of the grid-connected ESG system, the Jacobian matrix of the statespace shown in (7) can be derived based on the Lyapunov's first theorem [22]:…”

“…the domination of synchronous machines, which has lasted for many decades. In case of a fault, the presence of SynCons' electromotive force (EMF) can easily regulate nearby voltage [5][6][7] and assist triggering widely-used relay mechanisms, such as overcurrent protections and distance protections when local synchronous generators have been replaced by renewable sources. As to steady state operation, a SynCon can help regulation of frequency and voltage as well.…”

Adaptive transient overvoltage control strategy for wind farm based on data‐driven method

“…The second category is the external dynamic reactive power compensators control methods, such as SVG, static synchronous compensator (STATCOM), and unified power flow controller (UPFC) [18][19][20][21]. These devices can be used to rapidly suppress overvoltage.…”

Study on the priori method of vibration anomalies in the pipeline of a Synchronous condenser

“…Synchronous condenser plays an important role in the stable operation of power grid [1] . In the actual operation of the Synchronous condenser, vibration problems often occur in the pipes of cooling and lubrication system.…”