Technical Description of Static Compensators (STATCOM)

This paper presents application guidelines for a new generic plant controller model that can be used for renewable plant dynamic system analysis that may include the control of static compensators (STATCOMs), static var compensators (SVCs), and/or energy storage devices. The authors originally presented the need for such a model to the Western Electricity Coordinating Council (WECC) and contributed to various stages of the new model development led by WECC. As Independent System Operators (ISOs)/Regional Reliability Organizations (RTOs)/Transmission Service Providers (TSPs) are moving toward acceptance and use of generic models only the authors have for the first time applied this new model for an operating renewable plant. The new model was configured, parameterized, and tuned to control two STATCOMs and multiple switched capacitors/reactors to represent a master/auxiliary control strategy as implemented in the plant. Dynamic simulations show that the configured and parameterized model is performing properly as expected. This tuned model was submitted to the system operator for compliance with the interconnection requirements of the plant. This is the first submission of the new generic model for this type of control for a renewable project. The submitted model is appropriate for dynamic simulations, which are routinely performed by ISOs/RTOs/TSPs in system impact studies or transmission planning studies. This paper provides useful guidelines in applying this new model for similar projects.

To ensure a good quality of electrical energy at all points of the distribution network, the grid operators install several static compensators of reactive power (STATCOM) and many active power filters at some common coupling points PCC. This paper focuses on the operation of a static converter connected at PCC point performing the function of a static compensator (STATCOM) in the case of a voltage drop exceeding the standards and ensuring the function of an active power filter (APF) in the opposite case. This static converter ensures the regulation of the PCC voltage and eliminates the current harmonics produced by the non-linear loads connected to the grid. The control laws are designed to allow the converter to switch between the operation of a STATCOM and an active power filter. Furthermore, this research article represents an important aspect in scientific research concerning the control of FACT devices. A static reactive power compensator (STATCOM) for reactive power control and an active power filter (APF) performance are investigated by Improved Virtual flux based Direct Power Control (IVF_DPC). The association of a static converter with the (IVF_DPC) control allows to react in a very fast time to the grid perturbations. Simulation results of an improved control scheme (IVF-DPC) for STATOM / APF are affected by MATLAB / Simulink software to demonstrate the dynamic performance of the proposed control strategy. The adopted control scheme is implemented using the dSPACE 1104 board. Real time implementation results prove the efficiency and uniqueness of the adopted strategy

The direct on line (DOL) starting of a high power induction motor causes an acute voltage sag in the power supply system. Line to line and line to ground faults are some of the causes for voltage sags and voltage unbalance in the power supply system for industries and commercial buildings. This paper investigates hybrid compensation techniques to solve power quality problems arising from the DOL starting of a high power induction motor. The proposed solution utilizes the Static Compensator (STATCOM) and Static Synchronous Series Compensator (SSSC). In the proposed solution for voltage sags, STATCOM and SSSC are considered as the system components; therefore, a detailed mathematical model is developed for these components as well as a mathematical formulation of the proposed control schemes. Simulation results for STATCOM and SSSC based compensators are given.

With increasing focus on economical as well as environmentally friendly means for mass transit, rail transport is gaining renewed momentum in many parts of the world. This means investing in novel rail infrastructure as well as upgrading and electrifying existing facilities. The TEN (Trans-European Network) program within the European Union is but one current example of the importance attributed to more and better mass transit all over the world. The feeding of heavy rolling stock from AC grids will in many cases cause unacceptable voltage drops as well as unsymmetry between phases of the feeding grid. A traditional way to improve the situation would be to build additional power transmission lines and/or step up the feeding voltage to a higher level. This, however, may be undesirable or even impossible, for cost reasons as well as for environmental reasons. FACTS devices offer means of remedy within the existing feeding grid, restoring grid symmetry as well as voltage stability, and also mitigating harmonic distortion emanating from rolling stock. FACTS devices such as SVC (Static Var Compensator) and STATCOM (Static Compensator) are well proven and commercially available today. The paper treats dynamic load balancing of grids supplying power to rail transport, as well as dynamic voltage support and harmonic mitigation, by means of SVC as well as STATCOM.

In this paper, we present a detailed procedure to determine the semiconductor losses for both structures of a shunt STATCOM (Static Compensator), STATCOM based on Current Source Inverter (CSI) and STATCOM based on Voltage Source Inverter (VSI), both used for voltage unbalance compensation. As a first step, we study the VSI-based STATCOM and the CSI-based STATCOM used in high speed railway substations. Then we analyze the design and the sizing of the unbalance compensator in order to obtain an unbalance factor that does not exceed the limits imposed by the standards or by the energy provider. Following that, we compare the performances obtained with both structures VSI-STATCOM and CSI-STATCOM, after calculating the semiconductor power losses in the STATCOM converters. Finally, we validate our approach by simulation over real data of unbalance compensation caused by the new high-speed railway in Morocco. We use the tools MATLAB / Simulink/Simpowersys for performing our simulations.

Design and installation of a ±250 kVAr D-STATCOM for a distribution substation

This paper provides a systematic description of the fuzzy based construction of (Unified Power Flow Controller) UPFC along with the introduction of control strategy deployed in UPFC when it operates at a (Static Compensator) STATCOM and (Static Synchronous Series Compensator) SSSC. Model of the six-bus power network system is selected as evaluation structure. STATCOM and SSSC steady state and dynamic MATLAB simulation results are presented under various experimental conditions including unbalanced condition and faults. Novelty proposed work is of IEEE5 bus system is selected for test circuit. A critical case has been studied of the occurrence of three phase failures in IEEE5 bus model. The tests are correlated with that of UPFC and its absence. The conclusions drawn from simulations have verified that performance of the planned control strategy method, as long as the UPFC-stand on fuzzy resulting in a significant improvement in voltage stability compared to the(Proportional Integral) PI Controller.

This paper discusses comprehensively the dynamic performance of the FACTS control devices in multiple operations, hardware needed to complement the simulated models. This paper also presents the schematic and basic control of reconfigurable FACTS devices to realize the major voltage source converter FACTS Topologies: 1. STA TCOM (static compensator) 2. SSSC (Static synchronous Series compensator) 3. UPFC (Unified power flow controller) Furthermore, these control paradigms proposed in three prompt strategic directions to overcome outdated conventional control and other power control flaws in Pakistan power utilities wherein, including our neighboring countries (Iran, KSA, and India), and world-at-large, the FACTS been installed and in operation successfully. Whereas, Pakistan desperately needs this technology to hedge its power utilities to meet forthcoming challenges in power industry likewise significant growth in industry as well as domestic users under the declaration of government electrifying Pakistan 2007 to tap out power to its all rural areas by undertaking all possible means. Henceforth, the FACTS technology is an instrumental solution which will play vital and viable role to make this decree possible in following streams in parallel as listed below. 1. Set-up FACTS Laboratory at UET to develop prototype devices 2. FACTS feasibility study 3. Pilot project (at most contaminated area) This paper also culminates and enlists all three experiments results to encourage the elective/graduate course in electric power system.

In squirrel-cage induction generator (SCIG) powered micro-grid, continuously variable reactive power (CVRP) should be provided to stabilize the grid voltage when load is constantly changing. This paper proposes a novel CVRP compensator, which name is static VAR compensation magnetic energy recovery switch (SVC-MERS). Comparing with static compensator (STATCOM), the proposed device has some advantages in line frequency switching, small dc-capacitor and robustness. To begin with, operation principle of SVC-MERS has been briefly described in this paper. Secondly, optimal direct-voltage control (ODVC), which aims to broaden the reactive power compensating range, is proposed and verified by simulation in PSIM. It also has the advantages of sinusoidal output-current waveforms and restrains dc-capacitor voltage. Thirdly, a three phase SVC-MERS has been designed with delta connection and applied to voltage regulation in a 15kW SCIG powered micro-grid. Then experiments have been finished under different load conditions. Finally, experimental results confirm the conclusion.

Voltage stability is very important in a power system operation. This paper presents a detailed study on voltage stability and line losses of a radial distribution system incorporating Renewable Distributed Generation (RDG) using a two method approach of Index Based planning (IBP) and Genetic Algorithm (GA). RDGs have been largely adopted in most power systems due to their ability to meet increased electrical load faster and cheaply without expanding the transmission network, they have minimal environmental effects and they cannot be depleted. Formulation and solution of distribution voltage stability problem of a distribution network with RDG is very critical in the modern power system operation and control. Researchers have previously solved the voltage stability problem by obtaining optimal placement of Flexible AC Transmission Systems (FACTS), Static VAR Compensators (SVC) and static capacitors to provide reactive power to the system and improve the voltage profile. Other researchers have used Under Frequency Load Shedding (UFLS) and others have used optimal sizing and siting of DG units to improve the distribution network's voltage profile. This paper outlines a detailed research of the effect of interconnecting RDGs on the voltage stability and line loss of the IEEE 14 bus radial distribution system using Index Based planning and Genetic Algorithm. The results indicate the total voltage deviation and the total line loss for Photovoltaic DG, Wind DG and Static compensators (STATCOMS). In addition it gives a detailed formulation of the problem. The results obtained shows that appropriate sizing and location of RDGs improves the voltage profile and reduces the line losses of the radial distribution system.

Most of the pollution issues created in power system is due to the power quality problems like faults, harmonics etc. In this paper a grid connected fixed speed wind turbine induction generator subjected to asymmetric fault gets attenuated by unified power flow controller (UPFC) as it compensates the positive and negative sequence voltages thereby reducing the torque oscillations and improving the life time of the drain. It is the combination of static compensator (STATCOM) and static synchronous series compensator (SSSC). The control theory is based on vector control- dq(direct quadrature axis) reference frame fed PI, hysteresis control and fuzzy logic control using DSOGI-PLL(Dual second order generalized integrator- Phase locked loop). The proposed system is implemented using MATLAB / SIMULINK platform with and without Unified power flow controller. The effect of UPFC for fixed speed windturbine under faults is analysed using the above three controllers and its performance is evaluated.

A space vector modulation (SVM)-based switching strategy for a five-level diode-clamped converter that is adapted as a static compensator (STATCOM) is presented. The main feature of the proposed SVM switching strategy is that it enables voltage-balancing of the DC capacitors, under steady-state and transient conditions, with no requirements for additional control actions or auxiliary devices. A dynamic model of the five-level STATCOM for power system studies is also developed. On the basis of the developed model, a voltage controller to regulate the DC-side voltage and a decoupled current controller to control the AC-side real and reactive power are designed. Performance of the STATCOM and the corresponding controllers are evaluated on the basis of digital time-domain simulation studies in the PSCAD/EMTDC environment. The studies demonstrate capabilities of the proposed space vector modulation (SVM) strategy to maintain voltage balance of the DC capacitors and control the STATCOM reactive power exchange for various operating conditions.

This paper presents an application of Single-input Fuzzy Logic Controller (SFLC) to determine the control signal of a Static Compensator (STATCOM) synchronous for improvement of power system stability. This compensation scheme is relevant to Flexible AC Transmission systems (FACTSs) technology which is used worldwide to improve system dynamic performance. STATCOM improves the damping of electromechanical oscillations when used in transmission systems. The SFLC uses only one input variable which is called as signed distance. The SFLC has the advantages of reduced number of rules. Thus, generation, estimation and tuning of control rules are much easier while comparing with the existing conventional Fuzzy Logic Controllers (FLCs). The proposed control method is applied to control the AC and DC bus voltage of a STATCOM connected at a load bus in a Single Machine Infinite Bus (SMIB) System and also to improve the power system stability.

A large penetration of wind generation info the power system will mean that poor power quality and poor stability margins cannot be tolerated from wind farms. This requires that methods to improve power qualify and stability for such systems be found. The static compensator (STATCOM) with hybrid battery energy storage (BES) has great potential to fulfil this role, though considerable advances in the control of this system are still to be made. From an economic point of view, rating the STATCOM for steady-state power-quality improvement duty is appropriate. Rating the STATCOM to absorb large amounts of additional power in excess of its transient overload capability during network faults is inappropriate. A hybrid of BES and braking resistor is therefore proposed. A new hybrid STATCOM–BES control technique is developed and discussed in the context of improving the stability and power quality to fixed speed, induction generator, wind turbines. The variation of the network voltage, active and reactive power with the fluctuation of the wind generation is studied. A wind generation system with a STATCOM battery energy storage unit and the new control was simulated and the results demonstrate that both power quality and the stability margin can be improved significantly for wind farms.

Coordinated Voltage Control of Weak Sub-transmission Networks Considering Wind Power Variability