Problem Of Reactive Power Compensation Research Articles

Determining the Capacity and Installation Places of Compensating Devices in Electrical Networks

The problem of reactive power compensation in meshed electrical networks is investigated. A closed electrical network for a rated voltage of 220 kV, which contains three substations with loads equal to 80, 120 and 120 MW, and four lines, one of which connects it with the grid, is considered. Based on the specified load values, the capacitor bank capacities are determined. To determine more exactly the capacitor bank installation places, calculations of the entire network scheme were performed with all possible options for installing capacitor banks at the network substations. A few options for installing capacitor banks at different substations with which the power factor is improved significantly have been suggested, and the best one of them has been chosen.

Use of reactive power sources in improving the quality of electricity

The losses of power and electricity have sufficiently negative and significant impact on air transmission networks. In the supply of electricity and power to electricity consumers the power supply must be reliable and of high quality without interruption. In recent years the process of uninterrupted reliable and high-quality supply of electricity has become extremely complicated. Currently measures are being developed to calculate the solution of this issue as much as possible. The problem of reactive power compensation and the quality of electricity is directly related to the immediately consumer loads, voltage and frequency. It is also a process associated with increasing the value of the system's active power coefficient to balance the total power from the ac network, not decreasing the voltage value, and reducing the harmonic components of large fluctuations in nonlinear industrial consumer loads. Voltage storage is usually required to reduce voltage changes in the power line.

Optimal Phase-Balancing in Three-Phase Distribution Networks Considering Shunt Reactive Power Compensation with Fixed-Step Capacitor Banks

The black hole optimization (BHO) method is applied in this research to solve the problem of the optimal reactive power compensation with fixed-step capacitor banks in three-phase networks considering the phase-balancing problem simultaneously. A master–slave optimization approach based on the BHO in the master stage considers a discrete codification and the successive approximation power flow method in the slave stage. Two different evaluations are proposed to measure the impact of the shunt reactive power compensation and the phase-balancing strategies. These evaluations include a cascade solution methodology (CSM) approach and a simultaneous solution methodology (SSM). The CSM approach solves the phase-balancing problem in the first stage. This solution is implemented in the distribution network to determine the fixed-step capacitor banks installed in the second stage. In the SSM, both problems are solved using a unique codification vector. Numerical results in the IEEE 8- and IEEE 27-bus systems demonstrate the effectiveness of the proposed solution methodology, where the SSM presents the better numerical results in both test feeders with reductions of about 32.27% and 33.52%, respectively, when compared with the CSM. To validate all the numerical achievements in the MATLAB programming environment, the DIgSILENT software was used for making cross-validations. Note that the selection of the DIgISLENT software is based on its wide recognition in the scientific literature and industry for making quasi-experimental validations as a previous stage to the physical implementation of any grid intervention in power and distribution networks.

Control strategy for grid-connected inverters based on STATCOM reactive power compensation Research

The problem of grid-connected inverter reactive power compensation becomes a decisive factor for grid-connected power quality. To ensure the system unit power factor operation, this paper designs a reactive power compensation control strategy for grid-connected inverters based on STATCOM. On the basis of detailed analysis of the working principle of STATCOM, the grid-connected inverter model is built with the help of MATLAB simulation environment. The experimental results show that the use of STATCOM for grid-connected inverter reactive power compensation ensures stable grid-side output voltage of the grid-connected inverter and can improve the power factor of the system at the same time, which has certain reference significance for upgrading the grid-connected inverter design.

ON THE ISSUE OF COMPENSATION OF THE REACTIVE POWER LOADING UNIT OF THE INDUSTRIAL ENTERPRISE

This paper solves the practical problem of reactive power (RP) compensation of the load unit of the chemical plant. The peculiarity of this node is the presence of powerful asynchronous motors in the absence of synchronous machines.
 The load node is powered by a node substation located on the territory of the enterprise, on a 150 kV transmission line. Two step-down transformers TDNS–1600–150 / 6 kV, power supply load 0,4 kV from two transformers TM-2500–6 / 0.4 kV are installed at the settlement substation.
 The total active load of the unit is 12,540 kV, reactive — 7,210 kVAr. Currently, the main source of RP for the node is the power supply system (SPS) and partially generators of its own thermal power plant (TPP) with a capacity of 2–112 MW.
 As you know, factory TPP are sources of thermal energy for the technological needs of enterprises with low electricity production, so the possible task of choosing the best source of reactive power.
 The situation in the supply of electricity to industrial enterprises of Ukraine is complicated, it is determined by the ever-increasing tariffs for electricity, and is also regulated by the instructions on compensation of RP.
 Here it is necessary to note the latest instructions of the Ministry of Energy of Ukraine dated 06.02.2018 № 87 and the NERC supplement dated 28.01.2018, which regulate the procedure for settlements for the generation (consumption) of reactive power by industrial enterprises. A feature of the new methodology is the determination of the economic equivalent of reactive power (EERP), taking into account the cost of active energy. 
 Based on the standard power factor (according to the new method tg–0.25), the reactive power from the SPS for the load unit can be obtained in the amount of 3140 kVAr. Uncompensated RP in the amount of 4070 kVAr, and taking into account the increase in load by 5% — 4480 kVAr, it is advisable to compensate at the expense of the own needs RP.
 Given the above, the best option to compensate for the RP of the load node are the capacitor banks (BSC) to the lack of synchronous motors to drive the technological mechanisms of the enterprise.
 The classical method of technical and economic calculations for reactive power compensation, set out in the works of F.F. Karpova and L.V. Litvak, provides for the definition of such a parameter as the cost of active power losses, which includes the following components: a — specific costs due to the expansion of SPS to cover losses of main power (UAH / kW) and b — specific costs of electricity generation (approximately equal to the cost of electricity on power plant tires (UAH / kWh)). Determining the values of these components is significantly difficult to the lack of systematic data on the cost of electricity, especially in the requirements of the Ministry of Energy for the purchase of energy from renewable sources, which may affect the accuracy of some data, but not essential.
 According to the calculations: indicator a = 4110 UAH / kW, b = 0,573 UAH / kW and the specific cost of active power losses С0 = 6075 UAH / kW. Then the amount of costs for the transfer of reactive power from the power center to the voltage node will be 109.9 thousand UAH.
 Of the two options for installing BSC on the 6 kV or 0.4 kV side, you should choose the option of transmission of RP through step-down transformers TM-2500–6 / 0.4 kV, which is confirmed by the calculations performed (certainly take into account the significant difference in BSC cost of 0.4 kV).
 Estimated costs for the installation of BSC on the 6 kV side are: 4´20995 = 83980 UAH, taking into account the cost of the input device and the battery of capacitors with a capacity of 1125 kVAr. For each section of 6 kV busbars, two sections of over-regulated BSC are installed, as with a stable reactive load, if necessary, one section of capacitors can be completely disconnected.
 As you can see, a more economical option is to install BSC at the enterprise in the load node, taking into account the SPS requirement for consumption of RP in the hours of minimum active load. In the long run, this technical solution gives a significant economic effect.

Determining the Electrical Losses in the Electrical Supply Line of a Sprinkler Using Autonomous Asynchronous Generator

The use of an asynchronous generator to power the electrical equipment of the sprinkler is a comprehensive solution that allows you to reduce electrical losses in the supply line. The problem of reactive power compensation for sprinkler machines can be solved by dividing capacitor units into main and additional, the main one is to create the required excitation current in the asynchronous generator, and the additional one is to compensate for the reactive component of the electric motor current. Moreover, an additional unit is installed directly at the outputs of the booster pump to unload the line, and the main capacitor unit is installed near the asynchronous generator.

АВТОНОМНОЕ ЭЛЕКТРОСНАБЖЕНИЕ УСТАНОВОК ПО ДОБЫЧЕ НЕФТИ И ГАЗА С ОГРАНИЧЕНИЕМ РЕАКТИВНОЙ МОЩНОСТИ

The problem of reactive power compensation in the autonomous power supply net works of oil and gas production plants is considered, and it is determined that the use of submersible and thyristor compensators improves the operating modes of autonomous power generation plants

Efficient Operative Cost Reduction in Distribution Grids Considering the Optimal Placement and Sizing of D-STATCOMs Using a Discrete-Continuous VSA

The problem of reactive power compensation in electric distribution networks is addressed in this research paper from the point of view of the combinatorial optimization using a new discrete-continuous version of the vortex search algorithm (DCVSA). To explore and exploit the solution space, a discrete-continuous codification of the solution vector is proposed, where the discrete part determines the nodes where the distribution static compensator (D-STATCOM) will be installed, and the continuous part of the codification determines the optimal sizes of the D-STATCOMs. The main advantage of such codification is that the mixed-integer nonlinear programming model (MINLP) that represents the problem of optimal placement and sizing of the D-STATCOMs in distribution networks only requires a classical power flow method to evaluate the objective function, which implies that it can be implemented in any programming language. The objective function is the total costs of the grid power losses and the annualized investment costs in D-STATCOMs. In addition, to include the impact of the daily load variations, the active and reactive power demand curves are included in the optimization model. Numerical results in two radial test feeders with 33 and 69 buses demonstrate that the proposed DCVSA can solve the MINLP model with best results when compared with the MINLP solvers available in the GAMS software. All the simulations are implemented in MATLAB software using its programming environment.

Active power filter for reactive power compensation for the powerful sounding pulses shapers

The expediency of using a power active filter in the mode of reactive power compensation of the supply network for the powerful sounding pulses shaper power supply system of the Institute of ionosphere NAS and MES of Ukraine is shown. An analysis of the literature has been carried out, which shows the effectiveness of solving the problem of reactive power compensation, filtering higher harmonics of the power supply network using active filtering of higher harmonics of current or voltage using an additional energy source to obtain a compensating signal in the form of current or voltage. The choice of the power circuit for constructing a power active filter has been made. A voltage inverter on IGBT transistors is used as a power active filter. The basic principles of operation of the power active filter control system are described, which are based on the p-q theory of power and provide for the calculation of instantaneous values ​​of the task currents for each phase of a three-phase power supply system. The work of the Matlab-model of the power supply system of the shaper is shown, the oscillograms of the main energy characteristics of the shaper are given. As a result of using a power active filter, the current of the supply network becomes close to sinusoidal, and the power factor tends to 1. A positive effect on the efficiency of the shaper when the power active filter is included in the supply network is noted, which is due to the efficiency of compensation of the reactive power consumed by the shaper from the supply network. The simulation results are presented, in particular, graphs of reactive power change at the point of connecting the power active filter to the supply network, at different levels of reactive power consumption by the shaper. The results obtained confirmed the possibility of using a power active filter in the mode of reactive power compensation of the supply network when solving the problems of improving the electromagnetic compatibility of powerful sounding pulses shapers with the supply network, reducing losses and increasing the reliability of the shapers. Keywords: active power filter, reactive power control, control systems

Research on D-STATCOM Double Closed-Loop Control Method Based on Improved First-Order Linear Active Disturbance Rejection Technology

The application of a distribution static synchronous compensator (D-STATCOM) is the best technical means to solve the problem of reactive power compensation and harmonics. The D-STATCOM system has the characteristics of variable parameters, strong coupling, nonlinearity and multi-variability. In order to improve the speed of the dynamic tracking response and anti-disturbance capability of the D-STATCOM, the article proposes an improved Linear Active Disturbance Rejection Controller (LADRC) based on the total disturbance deviation control method. Combined with double closed-loop control, the inner loop takes the current as the state variable, and the outer loop uses the DC side output voltage as the state variable to achieve robust stability of the D-STATCOM and controller output. The simulation results show that the improved LADRC is more stable than the traditional LADRC in controlling the DC voltage waveform of the compensator, reactive current tracking and reactive power compensation waveform when it is disturbed, which verifies the superiority and feasibility of the improved LADRC.

Voltage and Loss Control for Long Range 10kV Power Transmission Based on Virtual-gap Controlled Reactor

The reactive power compensation problem prevalent in modern power systems makes the power distribution performance not fully utilized and the load power consumption of the equipment increases. According to the operation of the Yulin substation line and the load, the theoretical calculation of the reactive power compensation scheme is developed. The installation capacity, installation position, control scheme of the intelligent magnetic control reactive power compensation system are researched. Through the coordinated control at the beginning and the end of the line, the real-time regulation of the reactive power in the substation and the transmission line can achieve the effect of stabilizing the whole area voltage, improving the power supply radius and power quality. The system finally implemented the stability of the substation voltage and reduced the line loss, made the voltage of the power system stable within the utility required range.

Development of a model of automatic regulation of reactive power compensation for the oil and gas industry

Reactive power has a significant impact on the parameters of the power supply system in the oil and gas industry; as a result, there is a decrease in the quality of the electric network. The relevance of the study is justified by the tasks of improving the quality of electricity in the load nodes consisting of asynchronous motors, one of which is the reactive power compensation, including the calculation and automatic regulation of compensating devices. The aim of the article is to design and research a reactive power compensation control system to improve the quality of electricity. The article proposes a solution to the actual problem of reactive power compensation based on the proposed power quality control algorithm. The system of automatic control of reactive power compensation developed in the Matlab and Simulink software package allows us to generate parameters according to current measurements and adjust the voltage when the load operation mode changes. The use of MOSFET transistors in the control system made it possible to create the necessary compensation currents with a low content of higher harmonics that create distortions in the supply voltage and ensure high speed of the reactive power compensation unit operation.

Development of an algorithm for searching optimal solutions for compensation of reactive power

The problem of reactive power compensation, which includes many tasks, was substantiated in the work. Taking into account a number of specific problems of reactive power compensation and analysis of various electrical systems, an effective method of the calculation of the steady-state operation of the electrical network, on the basis of which the program “KRM_2021V7” was developed, is proposed. The method of nodal voltage, which was accompanied by the compilation of the system of equations and schematic matrices, among which the matrix of nodal conductivities and nodal loads were distinguished, is considered. An algorithm for finding optimal solutions for reactive power compensation is formulated and developed. Also, the work explains the use of genetic algorithms of mutation and population to find optimal solutions. The result of the calculation of losses in power lines for the considered electrical network is given.

Application of Modified Impedance Matrix to Determine an Initial Solution for Reactive-Power Compensation Problem

As an optimization problem, reactive-power compensation (RPC) in distribution networks has variety of technical and economical objectives and constraints. In order to solve the RPC problem, classic and heuristic methods have been applied. In distributed networks with large amounts of equipment, the RPC has a large dimension which could be a challenge for the aforementioned methods. So, having an initial guess or solution for buses that are suitable for compensator installation, lessens the mentioned challenge and thus improves performance of the solution procedures. Applying extended impedance matrix, this paper proposes a method to determine initial solution for the RPC problem. “Extended” means loads connected to buses are included in the impedance matrix. Inclusion of loads in the matrix gives more realistic initial solutions. The rationale behind it is that buses with more loads usually need more reactive composition. Two ranking lists of the buses that could be nominated for RPC have been considered in this paper: One list is obtained by the proposed method, and the other by the sensitivity analysis. Comparison of the mentioned lists in two typical distribution systems shows acceptable performance of the proposed method.

A Four-Winding Inductive Filtering Transformer to Enhance Power Quality in a High-Voltage Distribution Network Supplying Nonlinear Loads

This paper solves the problem of reactive power and harmonics compensation in a high-voltage (HV) distribution network supplying nonlinear loads. An inductive filtering (IF) approach where passive filters connect to the filtering winding of a four-winding inductive filtering transformer (FW-IFT) is presented to enhance the power quality of the public grid. This method can not only greatly suppress harmonic currents of the medium and/or low-voltage (LV) side, but also prevent them from flowing into the public grid. The new main circuit topology, where the FW-IFT has specific filtering winding by adopting the ampere-turn balance of the transformer, is presented. On the basis of the structure of the FW-IFT, the magnetic potential balanced equation and inductive filtering technology, its equivalent circuit and mathematical model are established, and the filtering performances are analyzed in detail. Simulation and experimental results rated at SN-10/0.38 of the FW-IFT are presented to prove the efficacy of the comprehensive enhancement of power quality on the grid side.

Application of a hybrid evolutionary algorithm on reactive power compensation problem of distribution network

Development of evolutionary optimization algorithms has provided more capability for enhancement of power system performance. To improve the performance of these algorithms, the combination of them can be a suitable option. This paper has proposed a hybrid algorithm based on combination of particle swarm optimization (PSO) and electromagnetic-like (EM) algorithms. The proposed algorithm covers the problems of trapping in local optimum problem of PSO and low convergence rate of EM. The optimal capacitor siting and sizing in distribution networks as the one of important problems of power system operators have been studied for validation of proposed algorithm performance. A comprehensive comparison has been carried out between proposed and other popular evolutionary algorithms. The results show that proposed algorithm has better performance for increasing the net saving value as the optimization objective function. Two well-known test systems of IEEE 34-bus and IEEE 85-bus power distribution networks have selected for these investigations.

Optimal Capacitor Placement in Wind Farms by Considering Harmonics Using Discrete Lightning Search Algorithm

Currently, many wind farms exist throughout the world and, in some cases, supply a significant portion of energy to networks. However, numerous uncertainties remain with respect to the amount of energy generated by wind turbines and other sophisticated operational aspects, such as voltage and reactive power management, which requires further development and consideration. To fix the problem of poor reactive power compensation in wind farms, optimal capacitor placement has been proposed in existing wind farms as a simple and relatively inexpensive method. However, the use of induction generators, transformers, and additional capacitors represent potential problems for the harmonics of a system and therefore must be taken into account at wind farms. The optimal location and size of capacitors at buses of an 80-MW wind farm were determined according to modelled wind speed, system equivalent circuits, and harmonics in order to minimize energy losses, optimize reactive power and reduce the management costs. The discrete version of the lightning search algorithm (DLSA) is a powerful and flexible nature-inspired optimization technique that was developed and implemented herein for optimal capacitor placement in wind farms. The obtained results are compared with the results of the genetic algorithm (GA) and the discrete harmony search algorithm (DHSA).

Features of compensation of a instantaneous reactive power in linear circuits at the transient mode and switched on load

Compensation of reactive power is one of the ways of increasing the electrical grid efficiency, theoretical foundations of which were developed at the beginning of the last century by scientists Frize and Budeanu. The development of effective control algorithms for reactive power compensation continues today. As usual, algorithms of reactive power compensation have an inertia of at least one period of network voltage. Therefore they cannot be used in transient mode because of the grid current non-stationarity. The problem of reactive power compensation in power grids with variable load is analyzed. An inefficient implementation of existing methods of reactive power compensation for this case is shown. The method of analysis of the transmitting energy between the source and the load during the transition process based on the theory of instantaneous power is proposed. The grid current on active and reactive components is expanded. The instantaneous value of power factor for estimation of reactive power value is proposed. To implement an assessment of the power factor instantaneous value the grid current represented as the sum of the steady and free components. For subsequent simplification of power factor calculation, the steady and free current components representation based on sine and cosine components is proposed. The power factor sign according to the current components values is analyzed. Time dependency of the current components in transient mode unlike for steady state is shown. The proposed method is adapted to transient processes. A method of instantaneous power factor value calculation, based on grid current calculation is proposed. The disadvantage of proposed method in transient mode is shown and proposed to estimate power factor value based on grid current and its derivatives. The procedure of calculation, prediction, and identification of power factor values based on expanded equation system is proposed. Principle of active and reactive power calculation on basis instantaneous power factor, sine and cosine current components is shown. Analysis of energy processes in the transient mode in a linear circuit of the first order is performed. A possibility of power factor negative values is shown. A reactive compensator design for transient mode is proposed. The principles of reactive power compensation based on power factor instantaneous values in transient mode are given. The necessity of active power compensation during time intervals when power factor has negative values is proved. The grid current shape after reactive power compensation is analyzed. The unipolar shape of the grid current and the same polarity with grid voltage insignificant part of the transient process is underlined. Shown, that such current behavior facilitates to the accumulation of the required energy in the reactive element within the minimum possible root mean square current of the electric grid that decreases stress to the grid during the transient process.Ref. 13, fig. 3.

Decentralized Reactive Power Compensation Using Nash Bargaining Solution

We consider a distributed reactive power compensation problem in a distribution network in which users locally generate reactive power using distributed generation units to contribute to the local voltage control. We model and analyze the interaction between one electric utility company and multiple users by using the Nash bargaining theory. On one hand, users determine the amount of active and reactive power generation for their distributed generation units. On the other hand, the electric utility company offers reimbursement for each user based on the amount of reactive power dispatched by that user. We first quantify the benefit for the electric utility company and users in the reactive power compensation problem. Then we derive the optimal solution for the active and reactive power generation, as well as reimbursement for each user under two different bargaining protocols, namely sequential bargaining and concurrent bargaining. Numerical results show that both the electric utility company and users benefit from the proposed decentralized reactive power compensation mechanism, and the overall system efficiency is improved.

Reactive Power Compensation Method Considering Minimum Effective Reactive Power Reserve

According to the calculation model of minimum generator reactive power reserve of power system voltage stability under the premise of the guarantee, the reactive power management system with reactive power compensation combined generator, the formation of a multi-objective optimization problem, propose a reactive power reserve is considered the minimum generator reactive power compensation optimization method. This method through the improvement of the objective function and constraint conditions, when the system load growth, relying solely on reactive power generation system can not meet the requirement of safe operation, increase the reactive power reserve to solve the problem of minimum generator reactive power compensation in the case of load node.