Reactive Power Compensation Scheme Research Articles

СУЧАСНІ ТЕНДЕНЦІЇ РОЗВИТКУ СИСТЕМ КОМПЕНСАЦІЇ РЕАКТИВНОЇ ПОТУЖНОСТІ

This paper surveys current trends and developments in reactive power compensation systems, elucidating their significance in enhancing system capacity and flexibility. By analyzing the capacity factor enhancement enabled by reactive power compensation, the study underscores its role in optimizing electricity delivery, thus conserving energy resources and facilitating the integration of renewable energy sources. It explores the key models and concepts driving advancements in reactive power compensation within power grids. As modern electrical systems grow in complexity, ongoing research into improving compensation methods becomes imperative to ensure the reliability and efficiency of industrial power grids. Future endeavors will involve developing a model utilizing real-world enterprise data to investigate the effects of technological variations in filter parameters on the performance of complex reactive power compensation schemes, encompassing both filters and capacitor banks. Keywords: reactive power, compensation systems, filter-compensating circuit, industrial power grid, electric power. Context. The paper considers the current trends used in the field of reactive power compensation, and the main directions of development of modern methods of reactive power compensation. Objective. The purpose of the work is to overview of current trends in the development of reactive power compensation systems, as well as an overview of possible ways of their effective application in various industrial networks. Methods. The paper presents a key aspect of reactive power compensation is its ability to increase system capacity and flexibility. By improving the capacity factor, utilities can deliver electricity more efficiently, reducing the need for excess capacity and thus conserving energy resources. In addition, this process plays an important role in supporting the integration of renewable energy sources such as wind and solar power, which often introduce volatility into electricity generation schemes. Results. The paper presents the main models and concepts in the field of reactive power compensation in power grids. Conclusions. Given the growing complexity of modern electrical systems, it is important to continue research into improving methods and means of reactive power compensation to ensure the reliability and efficiency of industrial power grids. In further research, it is planned to develop a model using a real enterprise as an example and investigate the impact of technological deviations of filter parameters on the steady-state and transient performance of complex reactive power compensation schemes, including not only filters but also capacitor banks.

A Differentiated Dynamic Reactive Power Compensation Scheme for the Suppression of Transient Voltage Dips in Distribution Systems

At present, with the construction of new power systems, the uncertainty of the system is increasing and the transient voltage stability of the power grid is becoming more and more complicated. For this reason, this paper proposes a differentiated dynamic reactive power compensation configuration method for suppressing transient voltage dip instability. The method first establishes a dynamic reactive power device configuration indicator system based on multiple-two-element notation, and then establishes a differentiated dynamic reactive power compensation device configuration model based on the node instability risk characteristics. The model takes the investment cost and suppression effect as the optimization objectives, and flexibly adjusts the optimization weights of its cost and suppression effect according to the high or low risk of the transient voltage instability of the compensation node, so as to realize the differentiated dynamic reactive power compensation. Compared with traditional compensation methods, differentiated compensation can significantly improve the economic benefits of reactive power compensation configuration. Finally, taking the IEEE39 node test system as an example, the improved TLBO algorithm is used to solve the model. The cost of differentiated compensation is reduced by 22.13%, with a similar suppression effect, which verifies the validity of the method proposed in this paper.

Reactive Power compensation Optimization of Distribution Network with Distributed Power Supply

In recent years, distributed generation has been fully developed, and its permeability is rising, which also brings great challenges to the reactive power regulation of the power distribution network. By analyzing the output characteristics of active power and reactive power of distributed power supply, in this article, a multi-objective optimization mathematical model of reactive power compensation is established, which takes the economy and security of the power distribution network into consideration. The results indicate that the reactive power compensation optimization model and the solution algorithm in this paper have good effectiveness and superiority. This thesis will provide the theoretical foundation and technology support for the design and realization of the DG reactive power compensation scheme.

Carbon Market Trading Mechanisms Considering Multi-Layer Reactive Power Compensation

In the context of achieving carbon peaking and carbon neutrality goals, focusing on coordinated efficiency in loss and carbon reduction, and promoting comprehensive green transformation of economic and social development are critical strategies. Line loss is an economic and technical indicator for measuring losses in a power system, and loss reduction is one of the important ways to achieve the carbon peaking and carbon neutrality goals in the power system. However, with the continuous increase in the power grid scale and the increasingly complex operation mode of the system, it is difficult to clearly quantify the carbon reduction benefits brought by system loss reduction. In order to synergize grid loss reduction and system carbon reduction, and generate economic and environmental benefits at the same time, this paper proposes a carbon market trading model that considers multi-layer reactive power compensation strategies. Based on the carbon emission flow model, a node carbon cost pricing is formed, and multi-layer reactive power compensation measures are set in the distribution network nodes to obtain an optimal loss reduction strategy, with the carbon market trading cost minimization as the objective. The effectiveness of the model is verified by simulating and analyzing four scenarios. Compared with the original system that does not consider carbon trading and reactive compensation, the model proposed in this paper can reduce losses by 20% and reduce carbon emissions by 5.7%. This paper is of great value for reactive power loss reduction management in distribution networks of a low-carbon background.

Reactive Power Compensation Strategy of the Electric Vehicle Connected to the Distribution Network in the Limit State Considering Voltage Constraint

To solve the voltage stability problem of electric vehicles connected to the distribution network in the limit state, a reactive power compensation strategy based on the holomorphic embedding method and electrical distance is proposed. Firstly, the load model of the electric vehicle charging station is constructed, and the limit of the charging power of the electric vehicle connected to a certain bus is obtained. Then, the power flow embedding equation of the power system is constructed by the holomorphic embedding method, and the analytical expression of the voltage rational function is introduced based on the Padé approximation algorithm. The voltage collapse point is solved by the distribution of zeros and poles of the rational function. Then, a method of reactive power and voltage control partition based on electrical distance is proposed. According to the principle of weak regional coupling and strong interval coupling, the power system is divided into several regions by spectral clustering and a k-means clustering algorithm. The order of the voltage stability margin value s is obtained by connecting the limit charging power to each bus of the power system. In this paper, the reactive power compensation strategy proposes to add reactive power compensation devices to the buses with the weakest voltage stability margin in different zones. Finally, compared with other reactive power compensation strategies 1 and 2, the reactive power compensation strategy provided in this paper is increased by 1.626121813 and 1.160494345 times, respectively. The superiority of this method is verified by simulation.

Analysis of Short-Circuit Fault Current Characteristics on AC Side of Wind-PV-Storage Integrated Grid Connected System

The penetration rate of Wind-Soloar-Storage integrated grid-connected systems in the power grid is getting higher and higher. However, the mechanism of its influence on the short-circuit current is still not deeply understood. This paper analyzes the low-voltage ride-through and reactive power compensation strategies of a Wind-PV-Storage integrated grid-connected system; the short-circuit process of the AC side is studied, and the voltage sag degree and limiting link affect the steady amplitude and phase of the current. Through establishing the Wind-PV-Storage integrated grid connected system model in PSCAD/EMTDC, theoretical analysis and verification are carried out on the influence of factors such as the collection line inside the station and different capacity distribution proportions of the station on the short-circuit current.

An Optimized Reactive Power Compensation Strategy to Extend the Working Range of CHB Multilevel Grid-Tied Inverters

In the cascaded H-bridge photovoltaic (PV) grid-connected inverter system, the power of PV panels may be unbalanced due to partial shading, aging, dust accumulation, temperature difference, and other reasons. The existing control methods have problems, such as weakened PV energy harvesting ability and the requirement of expanding the working range when the imbalance is severe. This article proposes an optimized reactive power compensation strategy (ORPCS) that first extends the operating range of the system to the maximum under unity power factor. Then, when the system exceeds the upper limit of unity power factor operation under severe imbalance, not only can the maximum PV output energy be harvested with the least amount of reactive power but also the PV voltage fluctuation is small with high-quality grid-connected current when ORPCS is adopted. Last but not least, under balance or mild imbalance yet maintain the advantages of the conventional carrier phase-shift SPWM methods. Simulation and experimental results demonstrate the effectiveness of the proposed method.

Coordinated voltage control for improved power system voltage stability by incorporating the reactive power reserve from wind farms

The absorption and output characteristics of reactive power of the doubly-fed induction generator (DFIG) greatly influence the voltage stability of PCC (Point of Common Coupling) where the wind farms are integrated into the bulk power grid. This study proposes a reactive power compensation strategy for coordinated voltage control (CVC) of PCC with large-scale wind farms to achieve the expected voltage quality of the power grid through a minimum amount of control actions in emergencies. To this end, the mechanism of reactive power and voltage control inside DFIG is first analyzed. Then, the concept of reactive power reserve (RPR) sensitivity concerning control actions is introduced and an index of voltage stability margin is proposed to evaluate and analyze the distance between the current operating point and the voltage collapse point by analyzing the relationship between reactive power reserve and voltage stability margin. In the event of an emergency, critical reactive power reserves are obtained to reduce the dimension and complexity of the control problem. The sensitivity of reactive power reserve and the control are formulated into a convex quadratic programming problem to optimize the control strategies for voltage stability. The proposed technology has been validated on the IEEE 39-bus system.

Research on Optimal Allocation of Reactive Power Compensation in Offshore Wind Power Transmission System via AC Cable Based on Controllable Reactor

The capacitance of submarine cables with the same length and the same voltage level is more than 20 times that of overhead lines, which makes the reactive power for AC transmission system of offshore wind power greatly increase and the power flow is complicated, and it is easier to produce a series of problems such as reactive power return, low power factor, increased network loss, and terminal voltage rise, which puts forward higher requirements for reactive power compensation configuration scheme. Combined with practical engineering cases, this paper introduces the reactive power and voltage characteristics of the sea breeze system, as well as the problems and shortcomings of conventional reactive power compensation schemes. Finally, the reactive power allocation optimization scheme based on the new magnetically controlled controllable reactor MCR is proposed, which has the technical and economic advantages of low running loss, saving investment and land occupation, etc. It can be used as a beneficial supplement to the reactive power allocation scheme for the transmission system of offshore wind power with AC cable and has the value of engineering popularization.

Mitigating Adverse Impacts of Increased Electric Vehicle Charging on Distribution Transformers

As the world is transitioning to electric vehicles (EVs), the existing power grids are facing several challenges. In particular, the additional charging power demand may repeatedly overload the traditionally-sized distribution transformers and adversely impact their operational life. To address this challenge, this paper proposes an EV-based reactive power compensation strategy for transformer overloading mitigation. Specifically, a low-bandwidth centralized recursive controller is proposed to determine a set point for the EV’s onboard charger’s reactive power. Importantly, the proposed strategy is practically implementable in existing distribution grids as it does not rely on smart grid infrastructure and is stable under potential communication delays and partial failures. This paper discusses the controller’s structure, design, and stability in detail. The proposed solution is tested with a realistic secondary distribution system considering four different EV charging scenarios with both Level 1 and Level 2 residential EV charging. Specifically, IEEE Standard C57.91-2011 is used to quantify the impact of EV charging on the transformer’s life. It is shown that with the proposed method, transformer overloading is significantly reduced, and the transformer’s life improves by an average of 47% over a year in all four scenarios.

A Novel Coordinated Control System to Reactive Power Compensation of Photovoltaic Inverter Clusters

With the development of new energy, a cost-effective reactive power compensation scheme is essential to the voltage stability of the power system for small-capacity distributed generation. This paper proposes a coordinated control scheme of inverter cluster which is based on the reactive power support capability of the photovoltaic inverter. Moreover, by using power angle vectors, a reactive power distribution algorithm is proposed to solve the poor power quality of the point of common coupling connecting source and load in the distributed generation station. Simulations verify the performance of the algorithm is better than the conventional static capacity distribute algorithm and dynamic residual margin distribute algorithm. Finally, the effectiveness of the reactive power compensation scheme and distribution strategy for improving power quality and regulation ability proposed in this paper is verified by operation experiments in the actual power station.

Research on optimization strategy of harmonic suppression and reactive power compensation of photovoltaic multifunctional grid connected inverter

In this paper, a new harmonic suppression and reactive power compensation strategy based on photovoltaic multi-functional grid connected inverter (PVMFGCI) and a three-layer optimization model based on adaptive ant colony algorithm are proposed for optimal control of power quality of grid connected photovoltaic (PV) power generation system. Here, an improved CPT (Conservative Power Theory) current detection method is used to extract harmonic and reactive current components from the load current, and a new PVMFGCI hierarchical optimization model is developed to optimize the power quality at the common connection point (CCP). The proposed three-layer optimization model is an improved form of the two-layer optimization model, which successfully solves the contradiction between the active power grid connection of the PV grid connected inverter and the power quality control. The main objective of the proposed three-layer optimization model is to meet the requirements of active power output of PV power generation, and at the same time, to utilize the remaining capacity of the inverter to control harmonics and compensate reactive power. However, when the remaining capacity of PVMFGCI is sufficient, PVMFGCI can reasonably allocate the remaining capacity through the three-layer optimization model to meet the optimal power quality at the CCP. In this process, the power quality of the microgrid is improved. PVMFGCI provides reactive power compensation, harmonic control and other power quality problems. In addition, when the remaining capacity of PVMFGCI is insufficient, it only needs to maximize the active power and make the harmonic distortion rate and power factor meet the grid connection requirements, which improves the utilization rate of PVMFGCI. The proposed techniques are modeled and the IEEE 33 bus systems are analyzed and their performances are verified experimentally on a developed prototype, in PV output active power variation condition, imbalance loading condition for linear/nonlinear loads, where it has shown a very good performance. The effect of harmonic control and reactive power compensation at each node of the system is obvious.

Marginal Cost-Based Reactive Power Reinforcement Using Dynamic and Static Compensators

The main philosophy of this article is to develop customer-persuaded electric power tariff scheme, based on the composition of additionally required services. Ancillary services may be categorized into desirable and essential electric power market services and so independent system operator (ISO) looks into the rights of all the utilities involved in the electric power market for getting the most acceptable rate of electrical energy in favor of all. Reactive power compensation, one of the 12 ancillary services underlined by North American Electric Reliability Council (NREC) along with Electric Power Research Institute (EPRI), is necessarily important to attend the voltage profile at load terminals. STATCOM, a dynamic compensator, has more advanced technologies over a fixed capacitor (FC), which is a static compensator; however, its involvement results in more financial burden to utilities. This article reinforces an adequate reactive power compensation scheme, for attending static and dynamic load disturbances, using ISE criterion-based proposed current-controlled STATCOM with FC in a grid-tied system. The composition of reactive power supplied by static and dynamic compensation is optimized using marginal cost, based on base and peak reactive power demand concept, keeping in mind the system frequency regulation. The results in terms of compensation scheme are compared for step changes in three load conditions and with and without static reactive power compensators.

Forecasting of Reactive Power Consumption with the Use of Artificial Neural Networks

Many electricity customers, particularly in the area of small and medium-sized enterprises, are characterized by a system of 3-phase unbalanced current consumption and the polarization of power factor in the individual phases. Strong variation of power factor in the different phases (often with both inductive and capacitive nature) causes the inability to install classic–a 3-phase reactive power compensators. Therefore, energy consumers are exposed to higher costs for the crossing of the contractual power factor. This paper describes the problem of reactive power forecasting with the use of artificial neural networks. For calculation, the Nonlinear Autoregressive (NAR) neural network was used for different input vector sizes and different numbers of neurons in the hidden layer for foreseeing reactive power generation. Results of simulations compared to real measurements confirm that it is possible to forecast the reactive power course, useful for optimal planning of reactive power compensation strategies.

Power system static and dynamic security studies for the 1st phase of Crete Island Interconnection

The island of Crete is currently served by an autonomous electrical system being fed by oil-fired (Heavy fuel or light Diesel oil) thermal power plants and renewables (wind and PVs). The peak load and annual electric energy consumption are approximately 600 MW and 3 TWh respectively; wind and photovoltaic parks contribute approximately 20% of the electricity needs of the island. Due to the expensive fuel used, the Cretan power system has very high electric energy generation cost compared to the Greek mainland. On the other side the limited size of the system poses severe limitations to the penetration of renewable energy sources, not allowing to further exploit the high wind and solar potential of the island. According to the Ten Year Network Development Plan (TYNDP) of the Greek TSO (Independent Power Transmission Operator S.A. IPTO S.A.), the interconnection of Crete to the mainland Transmission System of Greece will be realized through two links: A 150 kV HVAC link between the Peloponnese and the Crete (Phase I) and a HVDC link connecting the metropolitan area of Athens with Crete (Phase II). The total length of submarine and underground cable of the HVAC link will be approximately 174km; it is at the limits of the AC technology and the longest and deepest worldwide at 150 kV level. A number of studies have been conducted by a joint group of IPTO and Hellenic Electricity Distribution Network Operator (HEDNO) for the design of this interconnection. This paper presents briefly the power system static and dynamic studies conducted for the design of the AC link and its operation. Firstly, the paper presents the main results of the static security study regarding the calculation of the maximum power transfer capability of the link and the selection of the reactive power compensation scheme of the cable. Results from dynamic security analysis studies are also presented. The small-signal stability analysis concludes that a new (intra-area) electromechanical oscillation is introduced to the National System after the interconnection. The damping of the electromechanical oscillations is sufficient; however the operation of power system stabilizers at power plants located both at the mainland and at Crete power system can increase significantly the damping of important oscillation modes. Finally with respect to the risk of loss of synchronism after a significant disturbance in the system of Crete, such as a three-phase fault (“transient stability”)- enough safety margin is estimated by means of Critical Clearing Time calculations.

Investment Strategy of Reactive Power Compensation Scheme in Wind Turbine Distribution Network Based on Optimal Allocation

The development and application of new energy have been paid more and more attention by governments of various countries since the 21st century. It is of practical engineering significance to study reactive power compensation of wind turbine distribution network. In view of the problems of poor grid quality and increased active power loss caused by a large amount of reactive power transmission during the operation of wind farms, based on the improved genetic algorithm, aiming at the minimum compensation capacity and the minimum voltage deviation of load nodes, a multiobjective optimization scheme of reactive power in wind farms is proposed, and an example is analyzed in Matlab. The results verify the effectiveness of the improved genetic algorithm in reactive power optimization of wind motor.

Optimization of Solar Hybrid Power Generation Using Conductance-Fuzzy Dual-Mode Control Method

The functioning of a solar hybrid power system is investigated in this research using a unique fuzzy control method. Turbines, solar photovoltaics, diesel engines, fuel cells, aqua-electrolyzes, and other autonomous generation products are used in the hybrid renewable energy system. Further energy storage components of the system include the batteries, turbine, and ultracapacitor. This research incorporates a supercapacitor hybrid energy storage system (HESS) into a solar hybrid power generating system, allowing the consumption and energy storage space and power output to be significantly increased. This study’s approach incorporates a decentralized power generation system with a HESS while increasing electrical output in phases utilizing a dynamic reactive power compensation scheme and a conductance-fuzzy dual-mode control strategy. Due to a nonlinear behavior of photovoltaic (PV) devices’ power output, maximum power point tracking (MPPT) methods must be used to create the greatest power. Infrequently developing atmospheric circumstances, traditional MPPT algorithms do not work adequately. Modeling is used to determine the microgrid’s power output to the photovoltaic hybrid power generating organization, as well as the optimization method for each device in the network. The dynamic power factor correction scheme and also the conductance-fuzzy dual-mode control approach are primarily used in this study to optimize the solar hybrid renewable energy system.

Transient Performance Analysis of Reactive Power Compensators at LCC-HVDC Station Feeding Weak AC System

This paper focuses on analyzing the dynamic performance of various reactive power compensators at weak LCC-HVDC terminals. Four scenarios based on combination of active and passive reactive power compensation schemes are presented. The comparative performance analysis of various compensators in different types of AC and DC system faults are evaluated using electromagnetic transient simulation program PSCAD/EMTDC. The analysis shows that fixed capacitor has poor performance and results in reducing effective short circuit ratio of system, while STATCOM on the other hand, increases AC system strength and has significant performance in areas like immunity to commutation failure, suppression of temporary overvoltage, AC bus voltage regulation and fault recovery time.

Research on Dynamic Reactive Power Compensation Scheme for Inhibiting Subsequent Commutation Failure of MIDC

Commutation failure at the inverter side of an MIDC (multi-infeed HVDC) is usually caused by AC system faults. Suppose the converter bus voltage cannot recover to the normal operation level in time: in that case, the commutation failure will then develop into more severe subsequent commutation failures or even DC blocking, which will severely threaten the security and stability of the system. Dynamic reactive power compensation equipment (DRPCE) can offer voltage support during accident recovery, stabilize voltage fluctuation and inhibit any subsequent commutation failure risk. This paper proposes the optimal DRPCE configuration scheme for maximizing both inhibitory effect and economic performance. The simulation results on MATLAB-BPA prove the scheme’s correctness and rationality, which can effectively inhibit the risk of subsequent commutation failure and obtain economic benefits.

Rectifilter for electric arc plasma plant

This article presents the results of the development and research of a new type of AC-DC converter - a filter-rectifier (or rectifilter). The object of application of the proposed device is an industrial plant of electric arc plasma processing, the operation of which requires maintaining a constant value of the arc current and is accompanied by a high level of harmonic distortion and consumed reactive energy. From the point of view of the reactive power compensation and harmonic filtering strategy, the rectifilter can be attributed to active electric power filters and FACTS, however, from the position of the main function performed, it is a direct current source, an AC to DC converter, an active rectifier. This work describes in detail the principles of operation of the control system and the hardware architecture of the device. Mathematical modeling of the rectifilter and analysis of the graphs of the consumed alternating current, rectified current, analysis of the harmonic composition and power factor in comparison with the thyristor rectifier of an electric arc plasmatron were carried out.