Phase-Independent Reactive Power Compensation Based on Four-Wire Power Converter in the Presence of Angular Asymmetry between Voltage Vectors

The paper presents the reactive power compensation method that allows for reducing the active power flow even in the presence of angular asymmetry between voltage vectors of the utility grid. Reactive power compensation ensures the reduction of power transmission losses and therefore brings significant economic benefits to electricity consumers. The concept of the alternating current/direct current (AC/DC) converter for prosumer applications operating as a local reactive power compensator has been proposed. The system is driven by a multi-resonant algorithm, allowing for independent control of the reactive power in each phase. The proposed method was validated experimentally by using a prototype of the converter, programmable AC source, and grid impedance model. The method made it possible to cover the reactive power demand without unnecessary active power generation and thus to improve the efficiency of the analyzed prototype. This solution can be implemented particularly in radial grids and non-urban areas.

Analysis of the Response of a Static Reactive Power Compensator to Instability and Failure in Electrical grids

The reliability of electrical power systems has led to the implementation of new equipment with reliable technology to solve transient failures, in recent decades flexible AC transmission systems (FACTS) have been implemented in power grids, resulting in high levels of stability and control. One of the elements used is static VAR compensators (SVC), however there is very little information about the dynamic response of the device to network instability and electrical failures, for which Simulink analyses the response of the SVC. The device consists of a 47.1 MVar reactive power compensator and a 97.6 MVar inductive reactivator compensator, implemented in a three-phase 500 kV system. The results indicate the effectiveness of response against network instability while maintaining the stable voltage of the network, but against electrical failures the type and time of failure must be considered. In the case of phase-phase faults, the response of the SVC is limited with drops of 0.52 pu.

Impact of the Integration of a STATCOM Controlled by LQG/H2 Regulator in an Energy System

Nowadays, the reactive power consumption is becoming a serious problem for electricity network management. To overcome this problem, several solutions are proposed in the literature. In the present study, the static reactive power compensator (STATCOM) solution is used to keep the network voltage within its rated range. The STATCOM is modeled in the axes of Park reference frame and is driven controlled by a SVPWM strategy. Its control scheme is based on a multivariable Linear Quadratic Gaussian (LQG/H2) controller, which has the advantage of being applied to systems whose condition is not measured. Simulations are performed using the MATLAB/SIMULINK software. Results are presented, compared and discussed.

Enhanced Direct Reactive Power Control-Based Multi-Level Inverter for DFIG Wind System under Variable Speeds

A novel direct reactive power control strategy based on the three-level inverter topology (DRPC-3N) is proposed for a doubly fed induction generator (DFIG)-based wind power plant system. The robustness against parametric variations and control performances of the presented methodology are analyzed under random wind speeds, taking into account the effect of the heating of the windings as well as the saturation of the magnetic circuit. The performance indices include obtaining a sinusoidal AC-generated current with low THD and less ripples in the output. Moreover, the generator can be considered as a reactive power compensator, which allows for the controlling of the active and reactive power of the stator side connected directly to the grid side using only the rotor converter. In this study, unpredictable conduct of the wind velocity that forces the DFIG to operate through all modes of operation in a continual and successive way is considered. The received wind power is utilized to extract the optimum power by using an appropriate MPPT algorithm, and the pitch angle control is activated during the overspeed to restrict the produced active power. The simulation tests are performed under Matlab/Simulink and the presented results show the robustness and effectiveness of the new DRPC strategy with the proposed topology, which means that the performances are more sophisticated.

Converter Compensation of Reactive Power Consumed by the Induction Generato

Purpose: The purpose of the article is to present a reactive power compensation for small hydropower plants with an induction generator. The classic compensation with capacitors is discussed and its improvement is proposed. Instead of capacitors, a three level power electronic converter connected in parallel to the induction generator can be used to provide reactive power compensation. The purpose of the paper is to present the developed structure of an active compensator and its control method. The developed control method was verified on a laboratory stand. The project and the methods: As part of research, an active compensator was built as a three-level power electronic converter in topology with Neutral Point Clamped. Laboratory tests of a converter compensator were carried out on a stand equipped with an induction generator with a power of 7.5 kW. Laboratory system measurements were made using a power analyzer and an oscilloscope. Results: A control structure of an active compensator based on a voltage-oriented method was presented and discussed. The operation of the con- verter compensator has been verified on a laboratory stand equipped with a 7.5 kW induction generator. The compensator current reduces the reactive (inductive) component of the current consumed from a power grid to a value equal to zero. The reactive power compensator ensures that the tgφ power factor is maintained at a set value of zero, which corresponds to the total compensation of inductive reactive power consumed by an induction generator working in a hydropower plant. Operation of the active compensator did not cause a significant increase in the harmonic content in the current consumed from the power grid. Conclusions: The paper presents the issues regarding reactive power compensation in hydropower plants with induction generators. Commonly used capacitor compensation has been covered and as a result, it is proposed to replace it with power electronics converter compensation of reactive power connected in parallel induction generators. Active compensator provides compensation for the entire reactive power consumed by the induction generator. The use of the converter compensator of reactive power significantly contributes to the reduction of costs for reactive power incurred by the owners of hydropower plants. The reactive power compensator also has a positive impact on the operation of the entire power grid, power losses from the reactive component of the current on the impedances of power grid components are limited. Keywords: renewable source of electricity, reactive power, active compensator, induction generator Type of article: original scientific article

Closed Loop Reactive Power Compensation on a Single-Phase Transmission Line

Nowadays the power consumption is increasing significantly. Due to this, the transmission lines are heavily loaded and in turn results in instability of the line. So orderly transmission of power is essential. For the proper operation of the load the voltage has to be maintained within the acceptable limit. Due to the changes in load, the voltage level of the line also changes. The voltage levels can be improved by using the reactive power compensator like capacitor banks, series compensator, STAT COM and svc. Here, we considered the SVC as reactive power compensator. This paper presents the reactive power compensation for a 230v transmission line model with variable inductive load using SVC and designed in Simulink. Here we considered the SVC model which contains of anti-thyristors in series to the inductor and a shunt capacitor. The required reactance is fed from the inductor to the transmission line by changing the gate triggering pulse to the thyristor pair. So, the main disadvantage of the open loop var compensation using svc is the triggering to the thyristor pair has to be changed every time depending on the load. This can overcome by implementing it using the feedback loop. Here for the feedback, we used the PI controller. under The PI controller gives the required gating pulse to the thyristor pair. The performance of this model is studied variable load conditions.

Static Reactive Power Compensator Design, Based on Three-Phase Voltage Converter

At present, electrical network stability is of the utmost importance because of the increase in electric demand and the integration of distributed generation deriving from renewable energy. In this paper, we proposed a static reactive power compensator model with common direct current voltage sources. Converter parameters were calculated and designed to fulfill specifications. In order to ascertain the device response for different operating modes as reactive power consumer and generator, we developed the model’s power and control circuits in Matlab Simulink. Simulations were performed for different conditions, and as a result, the current and voltage waveforms and the circular power chart were obtained. This paper has theoretically proven it is possible to achieve the consumption or generation of purely active or reactive power by implementing a static reactive power compensator with common DC voltage sources.

Impact of the hybrid reactive power compensator on the power grid used a fuzzy PI regulator

The work presented in this article is a contribution to the problem of controlling reactive powers and voltages in an electrical network. Among these control tools, the static reactive power compensator (SVC) was chosen because of its simplicity of control. SVC is one of the Alternative Flexible Current Transmission Systems (FACTS) devices which help to solve the problems encountered in the operation of electrical networks, either on the distribution side or on the transport side. To increase its compensation efficiency in the face of harmonic currents which cause voltage distortion, we have introduced a three-phase harmonic filter. This new hybrid SVC is used to control the reactive power, the voltage and in addition to reduce the voltage distortion and the correction of the power factor in the electrical energy transport network. In order to improve its efficiency, two voltage regulation systems have been chosen in the control system for this compensator, the fuzzy PI regulator and the PIP regulator.

Design of a master power factor controller for an industrial plant with solar photovoltaic and electric vehicle chargers

The power factor of industrial facilities is typically inductive. The case study in this paper was based on a typical Malaysian 11-kV on-grid industrial system with renewable energy sources and electric vehicle charging station connected. The integration of renewable energy sources reduces energy consumption from the grid; it consecutively reduces greenhouse gas emissions. However, the integration of renewable energy sources such as solar photovoltaic operating at unity power factor results in a reduction of the industry’s power factor. According to the Malaysian Distribution Code, the power factor of a medium voltage industrial system should be more than 0.85 lagging. A long-term low power factor will reduce the related electrical equipment lifespan and increase the monthly electricity bills. A classic method to overcome this issue was by installing reactive power compensator devices, such as the synchronous condenser, static VAr compensator and static synchronous compensator. Studies had revealed that solar photovoltaic with appropriate control system design could perform short-term reactive power compensation. The control techniques used are either power factor control, active power control, reactive power control or any combination of them. However, neither the reactive power compensator devices nor the solar photovoltaic with a control system can regulate the industry’s power factor to an intended value throughout its operation. Thus, this paper presents a simple, relatively cost-effective design of a master power factor controller that is capable of regulating the industry’s power factor to an intended value throughout its operation with a single preset reference. In this research, an industry-grade system comprises an industrial load installed with a power factor-controlled capacitor bank, a power factor-controlled solar photovoltaic system, a bidirectional current-controlled electric vehicle charging system based on CHAdeMO 1.1 standard charging protocol and a master power factor controller was designed using the Matrix Laboratory/Simulink software. This paper has provided simulation results as proof that each of the designed equipment was functioning appropriately. The results also proved that the proposed master power factor controller was capable of regulating the power factor of the industrial system to above 0.85 lagging throughout its operation.