Impact Of Static Synchronous Compensator Research Articles

STATCOM integration into a DFIG-based wind park for reactive power compensation and its impact on wind park high voltage ride-through capability

This paper presents static synchronous compensator (STATCOM) integration into a doubly-fed induction generator (DFIG) based wind park (WP), analyses the impact of STATCOM on the WP high voltage ride-through (HVRT) capability, and proposes a transient function for the STATCOM to improve the WP HVRT capability. An actual WP is adopted as a test system. The STATCOM size is selected considering the grid code requirement for power factor control, and various wind turbine (WT) and medium voltage (MV) feeder outage scenarios. The WP HVRT capability is assessed with electromagnetic transient (EMT) simulations by analyzing the responses to a parametric voltage waveform. The external system is represented by a Thevenin equivalent. The pre-described voltage waveforms are applied to the Thevenin source in order to assess the conformity of the HVRT capability to Hydro-Quebec specifications. The WP simulation model includes all details regarding collector grid and overvoltage protection. The simulation results demonstrate that, STATCOM usage provides a noticeable improvement in HVRT capability of the WP, especially with the proposed transient function.

Impact of STATCOM and BFCL on the performance of distance relay and its improvement by adaptive setting for grid‐interactive offshore wind and marine current farm

This study explores the impact of the dynamic impedance of static synchronous compensator (STATCOM) and bridge type fault current limiter (BFCL) on the performance of distance relay and its improvement by adaptive setting for Grid Interactive Offshore Wind and Marine-Current Farm. For assessments, analytical results are presented under different STATCOM settings, low voltage ride through (LVRT) condition, and different types of fault conditions. Moreover, the presence of STATCOM and BFCL significantly changes the apparent impedance characteristic of the studied system. It is also seen that the presence of STATCOM likely to induce an under reach and overreach problem of distance relay. Further, the LVRT capability is significantly affected as STATCOM supplies reactive power to offshore wind generators during a short circuit on the grid side. It is found that the grid integration of OWF and MCF with STATCOM and BFCL is likely to induce mis-coordination and subsequently deteriorate the performance of distance relay, leading to system security problems. Therefore, this study proposed an adaptive setting in order to eliminate the simultaneous influence upon the dynamic impedance due to incorporation of STATCOM and BFCL on the distance relay setting. The simulation results show the efficacy of the proposed adaptive setting.

Advanced RTDS‐based studies of the impact of STATCOM on feeder distance protection

The studies of the performance of feeder distance protection with multiple installations of the static synchronous compensator (STATCOM) are presented. Detailed representation of delta-connected multi-level modular converter (MMC) STATCOM is modelled and its impact on feeder distance protection is analytically studied. A real-time digital simulation (RTDS) based hardware-in-the-loop testing platform is established using practical distance relays, multiple detailed MMC STATCOM models and realistic transmission data. Different types of internal/external faults at varying locations are simulated to investigate the STATCOM's impact on feeder distance protection.

Small-signal instability and supplementary coordinated damping-control of LCC-HVDC system with STATCOM under weak AC grid conditions

Static Synchronous Compensator (STATCOM) has been utilized to improve the dynamic behaviors of Line-Commutated-Converter based High Voltage Direct Current (LCC-HVDC) system under weak AC grid conditions. However, the close coupling between STATCOM and LCC system could result in system instability especially under weak AC grid conditions, which has not been addressed in the existing literatures. This paper developed a linearized small-signal dynamic model of a LCC system with STATCOM at the inverter busbar, and validated its accuracy by comparing time-domain responses from small-signal model and simulation results from PSCAD/EMTDC. Based on the small-signal model, this paper investigated the impact of STATCOM on the small-signal stability margin of LCC-HVDC by eigen-analysis and participation factor methods. The results show that under weak AC grid conditions, the close interaction between the control system of STATCOM (especially the AC voltage controller) and PLL of LCC system, deteriorates the system stability and may cause oscillation/instability. Then, this paper proposed a novel supplementary coordinated damping-control (SCDC), for LCC-HVDC system with STATCOM under weak AC grid conditions. The results based on the eigen-analysis and electromagnetic transient (EMT) simulations indicate that the proposed SCDC approach can effectively mitigate the oscillations/instability induced by the controller interaction of STATCOM and LCC system, thus effectively improve the stability margin of the overall system.

Performance of STATCOM-ES in Mitigating SSR

One of the advanced power applications using energy storage is the integration of energy storage technologies with VSC-based FACTS controllers. With the support of energy storage device, FACTS controllers will have the ability to exchange active power or energy with the ac network in steady state. This paper discusses the impact of Static Synchronous Compensator incorporating energy storage device (STATCOM-ES) on subsynchronous resonance (SSR). It also proposes the design of an auxiliary SSR damping controller (SSDC) for STATCOM-ES to damp the subsynchronous oscillations which the system is undergoing because of a series capacitor in the transmission system. The system under consideration is IEEE FBM which is modified to incorporate STATCOM-ES at the electrical midpoint. The investigation of SSR characteristics when a STATCOM - ES operating in bus voltage regulation mode is carried out by eigenvalue and damping torque analysis. Transient analysis based on the nonlinear model is also performed to validate the results obtained by conventional methods.

Adverse Impact of STATCOM on the Performance of Distance Relay

FACTS devices like the Static synchronous Compensator (STATCOM), are mostly used to enhance the maximum power transfer capability of the transmission Line (TL) system. A Matlab simulation model of Distance Relay protection of TL, with connected STATCOM at the mid-point for optimum power transfer is presented. The STATCOM’s impact on the operation of the relay is assessed with the effects on the relay misoperation in the third zone of protection coverage, during fault conditions, in four different locations.The wrong measured fault impedance by relay resulted to misoperation in zone 3 (under reach phenomena). The simulation result indicates a slight increase in the measured impedance of 1.33 Ω over the actually expected impedance setting (72.02 Ω) of the relay at 220 km protection coverage of zone 3 along the TL. This variation is about 4 km distance outside the expected distance protection coverage for fault in zone 3 as proven.

Impact of static synchronous compensator on the stability of a wind farm: Case study of wind farm in Tunisia

The static synchronous compensator is one of the FACTS (Flexible Alternating Current Transmission System) device capable of maintaining the stability of wind turbines during a sudden default. Among these faults, the voltage drops at the connection bus wind turbines. For this fault case, the static synchronous compensator intervenes by injection of the reactive power to compensate the voltage drop. In this article, as application case, we study the wind farm of Bizerte (north of Tunisia). This farm is composed of fixed speed aero-generators using squirrel cage induction generators. Our study begins with modeling the wind system. Next, we describe the technical requirements for connection of a wind energy system to the grid and outfit at the voltage dips (low-voltage ride through) according to STEG (Tunisian Company of Electricity and Gas). We also present the structure of static synchronous compensator. Finally, we present the simulation results of the wind farm under low-voltage ride through with and without static synchronous compensator.

Impact of STATCOM and SSSC on synchronous generator LOE protection

Loss of excitation (LOE) protection is one of the most important protections of synchronous generators. Nowadays, application of an impedance relay with two negative offset operation zones to protect LOE is prevalent; this relay measures the output voltage and current of generator to detect LOE. On the other hand, utilization of exible AC transmission systems (F ACTS) devices in power systems for different applications is soaring; these devices cause changes in voltage and current signals in the utilized power system. Therefore, this paper is dedicated to investigate the amounts of changes in the current and voltage signals measured by the LOE relay when the static synchronous compensator (STATCOM) and static synchronous series compensator (SSSC) are used. Research results show that the changes in the measured signals manipulate the operation of the relay. It is also shown that partial LOE culminates in an under-reach of the relay. In surveys conducted, various operational conditions of the power system and F ACTS devices are considered

Impact of static synchronous compensator on flux‐based synchronous generator loss of excitation protection

In order to increase the power transfer and providing the optimum utilisation of the power system capability, application of flexible alternating current transmission system (FACTS) devices technology, such as static synchronous compensator (STATCOM), has been attracted, in recent years. However, the STATCOM changes the voltage and current of the power system that disturb the operation of the impedance-based synchronous generator loss of excitation (LOE) protection. Then, this study proposes a new flux-based LOE protection method, in the presence of STATCOM, that is based on the local variation of the flux linkage of the generator available at the location of relay. The mentioned relay is independent of other generator protection relays without any coordination. In order to show the satisfying operation of the proposed method, some simulations have been carried out in the Matlab/Simulink software. A single-machine infinite bus and a three-machine infinite bus systems have been used in simulations. The results show that the presence of STATCOM has no important effect on the performance of proposed relay opposite to a negative offset relay with two protective zones (the widely used impedance method) which is affected by STATCOM operation.

Impact Analysis of midpoint Connected STATCOM on Distance Relay Performance

This paper presents the impact of the Static Synchronous Compensator (STATCOM) on the performance of distance protection of EHV transmission lines. A 400kV transmission system having midpoint connected STATCOM with its control circuit is modeled using MATLAB/SIMULINK software. The impact of STATCOM on distance relay for different fault conditions and different fault locations is analyzed. Simulation results indicate that the presence of the STATCOM in the transmission system significantly changes the line impedance seen by the distance relay to be lower or higher than the actual line impedance. Due to this the performance of the distance relay changes, either overreaches or under reaches. DOI: http://dx.doi.org/10.11591/telkomnika.v13i2.6987 Full Text: PDF

Setting Considerations of Distance Relay for Transmission Line with STATCOM

Distance relay plays an important role in the protection of transmission lines. The application of flexible AC transmission systems (FACTS) devices, such as the static synchronous compensator (STATCOM), could affect the performance of the distance relay because of compensation effect. This paper analyzes the application of distance relay on the protection of a transmission line containing STATCOM. New setting principles for different protection zones are proposed based on this analysis. A typical 500 kV transmission system employing STATCOM is modeled using Matlab/Simulink. The impact of STATCOM on distance protection scheme is studied for different fault types, fault locations, and system configurations. Based on simulation results, the performance of distance relay is evaluated. The setting principle can be verified for the transmission line with STATCOM.

STATCOM Impact Study on the Integration of a Large Wind Farm into a Weak Loop Power System

Recently, renewable wind energy is enjoying a rapid growth globally to become an important green electricity source to replace polluting and exhausting fossil fuel. However, with wind being an uncontrollable resource and the nature of distributed wind induction generators, integrating a large-scale wind-farm into a power system poses challenges, particularly in a weak power system. In the paper, the impact of static synchronous compensator (STATCOM) to facilitate the integration of a large wind farm (WF) into a weak power system is studied. First, an actual weak power system with two nearby large WFs is introduced. Based on the field SCADA data analysis, the power quality issues are highlighted and a centralized STATCOM is proposed to solve them, particularly the short-term (seconds to minutes) voltage fluctuations. Second, a model of the system, WF, and STATCOM for steady state and dynamic impact study is presented, and the model is validated by comparing with the actual field data. Using simulated PV and QV curves, voltage control and stability issues are analyzed, and the size and location of STATCOM are assessed. Finally, a STATCOM control strategy for voltage fluctuation suppression is presented and dynamic simulations verify the performance of proposed STATCOM and its control strategy.