Analyses of static and dynamic reactive power allocation between synchronous compensators and shunt capacitors to counter commutation failures

Abstract

Summary In traditional high‐voltage direct current systems, alternating current system faults can lead to commutation failures, which may further induce the blocking of converters. After the faults are cleared, the fast recovery of commutating voltage, as one key factor to avoid converter blocks, is closely related to dynamic voltage support. The dynamic voltage behaviour considering the reactive power characteristic of converters is analysed, where the polynomial approximation is applied to facilitate our studies. Focusing on the synchronous compensator, the transient voltage support ability is analysed, and then the steady state output of synchronous compensators is regarded as a parameter to take parametric analysis. Case studies show that the steady state VAR output of synchronous compensators has influence on the countering of commutation failures, and an optimal allocation can be found by analysing the results in the form of polynomials.

An Adaptive Phase Locked Oscillator to Improve the Performance of Fault Recovery from Commutation Failure in LCC-Based HVDC Systems

“…After the fault is cleared, the HVDC system is expected to recover from CF as soon as possible. Otherwise, continuous CFs may cause converter block [6], which threatens system security. It is important to improve the recovery performance to counter continuous CFs, and many previous works have been dedicated to this topic [7][8][9].…”

Current order‐based emergency control strategy for subsequent commutation failure elimination in HVDC

“…ability. 1,2 However, LCC-HVDC would be susceptible to commutation failure (CF) if voltage reduces due to AC faults in the receiving-end network, which may cause temporary outage of HVDC and influence the performance of the whole AC/DC hybrid power system. 3,4 Various indexes are proposed to recognize or evaluate the risk of CF.…”

“…Although newer technologies based on voltage source converters have been developed rapidly in the past decade, line‐commutated‐converter–based high‐voltage direct current (LCC‐HVDC) is still an important solution to alleviating the supply pressure of electrical energy in load center areas for advantages on large‐capacity and long‐distance transmission ability 1,2 . However, LCC‐HVDC would be susceptible to commutation failure (CF) if voltage reduces due to AC faults in the receiving‐end network, which may cause temporary outage of HVDC and influence the performance of the whole AC/DC hybrid power system 3,4 …”

A Control Strategy for Recovery from Commutation Failures in LCC-based HVDC Systems Based on Trajectory Prediction

“…The occurrence of CFs will inevitably cause many transients, such as temporary interruption of power transmission, voltage fluctuation, etc. If the CF continues to happen for a specific while, it will lead to the blocking of the HVDC system [2], threatening the safety of system operation. It becomes increasingly important to take further countermeasures to improve the immunity against CFs, and many papers have been dedicated to this topic, e.g., installing dynamic var sources [3][4][5], new converter structures [6,7], etc.…”