Dynamic Reactive Power Compensation Device Research Articles

Design and Verification of Cascaded Multilevel STATCOM Active Filter Function

STATCOM can be used as both dynamic reactive power compensation device and active power filter to improve the power quality of a power grid. This paper describes the active filter function implemented into an existing STATCOM control. The paper explains firstly the filtering control system of the STATCOM, starting from the introduction of active power filter principle, harmonic current detection and tracking control. After that, the parameter design, open-loop characterization and simulation verification of the proposed filtering control scheme are carried out. The PSCAD simulation results show that the active filtering control scheme proposed in this paper can effectively reduce the harmonic content in the system and has good stability.

Research on Reactive Power Coordination Control Strategies of Multi-Infeed Line-Commutated Converter–High-Voltage Direct Current Systems

For a receiving-end power grid with multi-infeed LCC-HVDC systems, simultaneous commutation failures may seriously threaten the safe and stable operation of the system. To evaluate the impact of commutation failure and improve the voltage stability of the commutation buses in multi-infeed HVDC systems, this paper proposes a method for evaluating the voltage stability of commutation buses and a reactive power coordination control (RPCC) method for commutation failure of multiple HVDC systems. Firstly, three indicators and the entropy weight method are adopted to comprehensively evaluate the voltage stability of commutation buses. Then, an RPCC method is proposed to resist commutation failure. The proposed RPCC method uses the voltage interaction factor (VIF) to screen out DC systems that are strongly related to dynamic reactive power compensation devices and activates the devices to provide RPCC to the DC systems through an auxiliary controller. Finally, the effectiveness of the proposed method is verified through a practical example of the Jiangsu power grid.

Nonlinear Transient Mathematical Model of Large-Capacity Synchronous Condenser Based on Time-Varying Reactance Parameters

Large-capacity synchronous condenser (SC) is an essential dynamic reactive power compensation device in an Ultra-high voltage direct current (UHVDC) transmission system. The particular transient operating state and structural characteristic of SC lead to a severe magnetic saturation effect during transient operation. To accurately describe the dynamic characteristics of SC, it is urgent to establish a transient mathematical model considering the magnetic saturation effect. Therefore, this paper proposes a nonlinear transient mathematical model for SC based on time-varying reactance parameters and gives a calculation method for time-varying reactance parameters. The mathematical model proposed in this paper is verified by taking a 300MVar SC as the research object. This condenser is connected to the power grid at the sending end of the UHVDC transmission system. The proposed mathematical model, the traditional fixed-parameter transient mathematical model, and the saturated standard SG model used in the power system were used to simulate the voltage generated by dynamic reactive power compensation characteristics of SC during a drop failure. Compared with the fault test results, the accuracy of the proposed mathematical model is verified. The effect of magnetic saturation on the dynamic reactive power compensation characteristics was analyzed, respectively. In addition, the accuracy of the proposed mathematical model is closer to the actual motor state, which is helpful for further research on the operation analysis and state monitoring of SC.

Research on the influence of distributed generation and its grid connection on power system

Abstract China’s per capita resources are scarce and consumed very quickly. New energy power generation has the characteristics of green, environmental protection and renewable, and it is the main development direction of the current and future power industry. With the continuous expansion of new energy power generation and grid-connected scale, various adverse effects brought to the power grid in the process of grid-connected are gradually emerging and becoming more and more serious.This paper briefly introduces the distributed power generation, and then studies and analyzes various problems brought by the grid connection of new energy to the power system from the four aspects of grid voltage, grid harmonics, grid frequency, and grid protection, and gives some solutions. For example, if the power generation equipment meets the grid-connection standard, a real-time monitoring device for power quality and a dynamic reactive power compensation device can be installed; for harmonic pollution problems, multi-pulse converters and power filter devices can be used; for power quality problems in the distribution network, the structure of the power grid can be optimized., Reasonable selection of the impedance ratio of the circuit, etc.

Research on Reactive Power Compensation Based on Magnetic Saturation Controllable Reactor

With the improvement of the automation level of the power system and the development of power electronic equipment, the magnetic saturation controllable reactor will surely become indispensable reactive power compensation equipment. But there are few researches on it at home and abroad. In the power system with its superior performance the magnetic saturation controllable reactor studied in this article is a static dynamic reactive power compensation device, which mainly uses lagging inductive reactive power to offset the leading capacitive reactive power. In this paper, its structure and working principle are studied in detail, electromagnetic calculation and simulation analysis are carried out, and genetic algorithm is introduced to optimize it. From theory to practice, a thorough discussion is made to make up for the blank of this direction.

Analysis for action degree and influence factors of harmonic interaction in multi-wind farms

With the increasing proportion of wind power in the power system, a significant threat is posed to the safe and stable operation of regional power grids and the consumption of the new energy by the harmonic interaction effects among wind farms. Aimed at the problem of mechanism for the harmonic interaction between wind farms and the degree of influence, an aggregation equivalence method of wind farms in harmonic power loss is proposed, where the complexity of wind farm equivalence calculation is reduced. Based on this, a harmonic impedance model of multiple wind farms grid-connected system is established, and the mechanism of harmonic interaction influence among the wind farms is revealed. The definition and calculation method of harmonic current interaction factor is presented, where the relationship between the harmonic current interaction and the potential factors, i.e., the coupling impedance, the dynamic reactive power compensation devices, and the number of wind turbines connected to the grid among multiple wind farms, is quantitatively analyzed. Finally, a typical wind farm of new energy base in Northwest China is used as a toy example to verify the effectiveness of the harmonic current interaction factor in the characterization of the interaction strength within multiple wind farms.

Optimization modelling of HCMC-STATCOMs for offshore wind power based on PSCAD

Under normal circumstances, the voltage fluctuation of the wind farm’s grid connection point is mainly caused by the volatility of wind power output. In recent years, with the clustering development of offshore wind power, the voltage fluctuation brought by the output fluctuation of wind power is becoming more and more notable. The main method of improving the reactive voltage problem of wind farms is to add more static and dynamic reactive power compensation devices. Hybrid cascaded multilevel converter STATCOMs (HCMC-STATCOMs) don’t need transformers to increase the device capacity and decrease the harmonics on the output voltage, which is effective in reducing the device cost and volume. This paper firstly introduces the topology and operation principles of an HCMC-STATCOM and then carries out a comparative study on HCMC-STATCOMs and traditional cascaded STATCOMs. Finally PSCAD/EMTDC is applied to model and simulate HCMC-STATCOMs. The simulation result shows that the reactive power of HCMC-STATCOMs can accurately vary according to the system’s demand on reactive power. This means that HCMC-STATCOMs have good dynamic performance and the harmonic contents in the output phase voltage and AC current are quite small. As a dynamic reactive power compensation device, HCMC-STATCOM can be adjusted in real time according to the system’s reactive power requirements, and has the advantages of small volume and low cost. The simulation results show that the properties of HCMC-STATCOMs are advantageous for the operation and control of the system and applicable for the dynamic reactive power configuration of offshore wind power.

Voltage prevention and emergency coordinated control strategy for photovoltaic power plants considering reactive power allocation

This paper proposes a voltage prevention and emergency control strategy that consists of coordinately arranging multiple reactive power sources in order to handle the point of common coupling (PCC) voltage fluctuation and stability in large-scale PV power plants. When a disturbance occurs at the PCC, dynamic reactive power compensation devices are coordinated preferentially to support the PCC voltage. After the disturbance is cleared, the reactive power in dynamic and fast devices is transferred into static and slow devices so that the static VAR generation (SVG) can maintain a large power margin for coping with the next disturbance. Moreover, the reactive power output of the individual inverter in PV power plants is coordinately allocated using a model to optimize the in-station voltage distribution. Finally, the effectiveness of the proposed control strategy is verified by an example simulation of a practical large-scale PV power plant.

Research of the Exciting Current Detection Method of MCR

Magnetic valve controllable reactor (MCR) is a kind of dynamic reactive power compensation device. The exciting current of MCR is one of the important indexes of operating condition of MCR. This paper firstly analyzed the principle of MCR, and deduced the relationship between the exciting current and the output current, verified by MATLAB/SIMULINK. And then an effective method to detect the exciting current was proposed by this paper. The method has the advantages of optical fiber isolation, high detection precision, strong anti-interference, etc. Finally, a 220v/1200var MCR was experimented in detail. The results demonstrate the accuracy of the theoretical analysis.

The Improved Five-Zone Control Theory with Considering Dynamic Reactive Power Compensation Device

The “five-zone” control theory is a kind of Reactive power integrated control theory With the device as the control object directly which is different from the traditional “nine-zone” theory . It has high control precision and good control effect and has a broad application prospect. However, with the appearance of New type of dynamic reactive power compensation device, the basic five-zone control theory can’t meet the new demand In this paper, on the basis of the traditional "five-zone"theory, considering the dynamic reactive power compensation device, the traditional five area boundary is improved. Based on the improved chart on the basis of the five area, defines a new type of five area chart control method, and finally verifies “improved five-zone” control method by simulation.

A Dynamic Reactive Power Compensation Method of Super High-Power and High-Voltage Motor

According to the low power factor and low running efficiency, a dynamic reactive power compensation method of the super high-power and high-voltage motor is proposed in this paper. The following works have been done in the study: topology of the dynamic reactive power compensation device; principle of the dynamic reactive power compensation method; control system of the dynamic reactive power compensation device; implementation of the dynamic reactive power compensation method. The amount of reactive power compensation can be adjusted smoothly and dynamically in the process of the super high-power and high-voltage motor soft-starting. The research of this paper has laid a theoretical foundation for this compensator in industrial applications. The novel design is characterized by flexible parameter setting, excellent soft starting performance of the super high-power and high-voltage motor and bright prospect in application.

Research on a Dynamic Reactive Power Compensation Method of Composite Power Load

A large number of inductive loads need the reactive power, and the amount of the reactive power compensation is different in a state of work. The traditional static reactive power compensator is difficult to meet the needs of the reactive power compensation for the composite load reactive. Therefore, a dynamic reactive power compensation method of the composite power load is proposed in this paper. The following works have been done in the study: principle of dynamic reactive power compensation control method, topological structure of dynamic reactive power compensation device, and implementation of the dynamic reactive power compensation control method.

Research on Cascaded H-bridge SVG

Due to the sharp increase of the non-linear loads, the power quality lagged behind the need for an adequate power system. With a fast response, low loss, low output harmonic current, SVG has become the mainstream of dynamic reactive power compensation devices. The paper introduces a multilevel cascaded H-bridge SVG, featured with DSP+FPGA dual-core control unit and fault-tolerant redundant system, which will enhance the reliability and dynamic response, reduce the switching loss and equipment cost, and increase the efficiency of the reactive power compensation. Through instructing the MATLAB simulation model of SVG and testing model machine, the design correction of medium voltage SVG power circuits and parameters is verified. The model machine is working well.

Simulation on Multi-Objective Wind Power Integration Using Genetic Algorithm with Adaptive Weight

Aiming at problems which were brought by large-scale wind power integration, and the problem of multi-objective reactive power optimization considering the coexistence of discrete variables and continuous variables, a method of simulation based on genetic algorithm with adaptive weight is brought out. A solving thinking presents that capacitor switching and transformer tap adjusting and other discrete equipments are first, and the action sequence of generator and dynamic reactive power compensation (DRPC) devices and other continuous equipments setting follows, which is presented that optimization problem is decomposed into continuous variable optimization and discrete variable optimization, then they are solved respectively and cross iteration until convergence. In view of the optimization complexity and the coexistence of discrete variables and continuous variables, genetic algorithm with adaptive weight is presented for finding global optimal solution. Case studies show that the proposed thinking and algorithm for solving multi-objective reactive power optimization are reasonable.

A Novel D-STATCOM Synthetical Optimization Configuration Method for Stability Control

Basic on dynamic analytic method and the trajectory sensitivity index to determine the optimal installation location , this paper propose a new D-STATCOM configuration method to synthesize the index of nodes voltage stability. The trajectory sensitivity index can reflect the general dynamic support effect under various faults, the best configuration scheme can be determined. The result reflect the new method have better play the role of dynamic reactive power compensation device. IEEE39 node system take as the example, the results show the effectiveness of the new method.

66 kV SVC Light Control Water-Cooled Valve Protection and Application

Improve power quality problems, the company introduced the "tag through 66kV Static dynamic reactive power compensation device (SVC)", which means water cooling valve parts, using the international advanced technology and light control thyristor, the real control cabinet and valve all-fiber connections between groups, no valve trigger circuit boards, etc., to ensure safe and reliable high-pressure environment. Light control while protecting 66kV more stable water-cooled manifold, also designed the various protection functions. Reactive power compensation device based on electrical design principle, the protection of the valve design principles, summarized the valve characteristic is a light-controlled thyristor trigger and pulse trigger laser fiber distribution device as one of the valve, the valve overcurrent analysis protection, undervoltage protection, return status display, RC protection, BOD protection, protection and cooling system valve structural protection, light control demonstrates the necessity of 66kV water cooling valve protection; through the reactive power compensation and benefits case situation the comparative analysis to verify the correctness of the application of SVC devices.

The Design of Dynamic Reactive Power Compensation Device on Segmented Control Mode

For metallurgical industry perceptual load fluctuations large, and distribution station bus power factor low, and power loss high problems, based on reactive power compensation principle of apparent power does not variable, and used SVC structure forms, has made sectional type compensation control mode, and based on power factor of closed-loop control method, has researched the dynamic reactive power compensation device, by the check of practical run, the feasibility has been proved of the control method, and it has a clear compensation effect and wide practical range and other outstanding features.

Reactive Power Compensation of Distribution Network Based on Bacterial Colony Chemotaxis Algorithm

Reactive power compensation of distribution network is an important method to improve power quality and voltage stability, while reducing the power loss of the distribution network. In this paper the objective function is built to minimize all the costs which include power loss costs and investment of the dynamic reactive power compensation device divided into each year. The actual operation of the distribution network is simulated considering light, normal and heavy load operation conditions. Bacterial colony chemotaxis (BCC) algorithm is used to determine which nodes to install the compensation devices. The calculation of reactive power compensation is done with the back/forward sweep algorithm adapting to the radial distribution system. In order to compensate three different load conditions separately, the fixed part and the switching part of the dynamic reactive power compensation device are used. This method applies to 28-node system, the result demonstrates that the method is feasible and effective.

Current Detection Simulate for STATCOM Dynamic Compensation System

In view of low-pressure area for dynamic reactive power compensation device application present situation, a more advanced static reactive power compensation techniques was proposed that is STATCOM (Static Synchronous Compensator-STATCOM) which based on the modern power electronic technology, and it applied to the low-voltage dynamic reactive power compensation area, developed a new and more advanced low-voltage dynamic reactive power compensation device. In this paper, STATCOM compensation system simulation model was established in MATLAB6.5, futher to study its real-time compensation. Theory analyze and simulation results indicate that compare with static capacitor compensation，dynamic compensation achieved zero phase angle between power source current and voltage on rating frequency，demand for power supply rating power is reduced and power transmission performance is ensured.

Research on Reactive Power Compensation Algorithm Based on Game Theory in Wind Farm

In current, constant speed of asynchronous generator system has been used wind farm in China areas. But because of that abilities of reactive power control helpless, reactive power have been provided by grid. In view of the above situation, the feasible measures are adopted in the wind dynamic reactive power compensation devices. The asynchronous machine transient process used reactive power to keeping voltage of machine has been provided. This article introduced the Game Theory in economics to the area of reactive power compensation. This new method of the share of reactive power in wind farm, will improve wind farm reactive power compensation too vague to efficient in the moment. In the meantime, the share of reactive power algorithm analysis process have bee bullied in this paper. For the research in the future, it proposed supplementary opinions.