An Integrated High Side Var-Voltage Control Strategy to Improve Short-Term Voltage Stability of Receiving-End Power Systems

Abstract

To make better use of local generators' dynamic var reserve to improve short-term voltage stability (STVS), this paper proposes an integrated high side var-voltage control (IHSV C) for power plants in receiving-end power systems. The IHSV C consists of a plant-level multi-machine var coordinator (MMVC) and several unit-level high side voltage controllers (HSVCs). MMVC coordinates the reactive power output among generators and provides control parameters for HSVCs, while HSVCs can maintain the voltage of a pre-defined voltage control point (VCP) by regulating the voltage reference of the excitation control of each generator. Therefore, when the system suffers a serious fault, IHSV C can drive the generators to provide stronger var support. Consequently, the voltage stability can be improved. A conceptual model of the receiving-end power system in China Southern Power Grid (CSG) is established, and the IHSV C has been validated through a simulation analysis on the system. Both time-domain simulation results and the voltage sag severity index (VSSI) have fully demonstrated its performance. Therefore IHSV C offers a new and effective approach to improve STVS of receiving-end power systems.Index Terms-Dynamic var reserve, high side voltage control, receiving-end power systems, short-term voltage stability, var/voltage control.

Optimized reactive power support strategy for photovoltaic inverter to intensify the dynamic voltage stability of islanded microgrid

“…Therefore, during catastrophic disturbances, for example, severe fault or disruption of power supply, maintaining the voltage within predefined limits becomes a challenge 3,4 . The postcontingency voltage stability problem can happen within a short time frame of just a few seconds in two ways: (a) fault‐induced delayed voltage recovery (FIDVR) and (b) voltage instability (VI) 5,6 . For FIDVR, the system cannot maintain the profiled value of voltage for some seconds, which can cause curtailment of voltage‐dependent loads and also DGs can be shut down depending on the relay settings.…”

“…For FIDVR, the system cannot maintain the profiled value of voltage for some seconds, which can cause curtailment of voltage‐dependent loads and also DGs can be shut down depending on the relay settings. Furthermore, cascading trip off of the generators can happen due to the further reduction of voltage which may not be recovered and ultimately blackout can occur at the area 6 . Therefore, VI issue is a threat for a system, and for inverter‐based MG this threat becomes terrible owing to poor ride through capability of the sources, which adversely affect the stability.…”

Dynamic Voltage Support by TL-PV Systems to Mitigate Short-Term Voltage Instability in Residential DN

“…Generally, short-term voltage instability (STVI) involves fast and complex load dynamics, and occurs in the time frame of few seconds [2]. There are mainly two types of STVI problems: (i) fault induced delayed voltage recovery (FIDVR) and (ii) voltage instability [3,4]. FIDVR is a phenomenon whereby post-contingency voltage remains at considerably reduced level for several seconds [5].…”

“…On the other hand, voltage instability occurs while the post-contingency voltage reduces further and cannot be recovered. Voltage instability is the prior stage of voltage collapse that may lead to a blackout in an area [4].…”

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