Series Compensation Devices Research Articles

Study on the characteristics of secondary arc current of UHV high compensation degree TCSC line under the fine-tuning mode

Abstract In the transmission line, the series compensation device is often used to improve the transmission capacity. However, when the fixed series capacitor (FSC) is used in high compensation series compensation device, the stability margin cannot meet the requirements. Therefore, thyristor controlled series compensator (TCSC) is often installed in transmission lines to improve the transmission capacity of the line and the stability of the system. For cost considerations, the hybrid compensation mode of FSC and TCSC is often adopted. However, when a single-phase grounding fault occurs in a transmission line with increased series compensation degree, the unreasonable distribution of FSC and TCSC will lead to the excessive amplitude of secondary arc current, which is not conducive to rapid arc extinguishing. To solve this problem, this paper is based on 1000 kV Changzhi-Nanyang-Jingmen UHV series compensation transmission system, using PSCAD simulation program to established UHV series compensation simulation model, The variation law of secondary arc current and recovery voltage during operation in fine tuning mode after adding TCSC to UHV transmission line is analyzed, and the effect of increasing series compensation degree on secondary arc current and recovery voltage characteristics is studied. And analyze the secondary arc current and recovery voltage when using different FSC and TCSC series compensation degree schemes, and get the most reasonable series compensation configuration scheme. The results show that TCSC compensation is more beneficial to arc extinguishing under the same series compensation. Compared with several series compensation schemes, it is found that with the increase of the proportion of TCSC, the amplitude of secondary arc current and recovery voltage vary greatly. Considering various factors, the scheme that is more conducive to accelerating arc extinguishing is chosen.

Congestion management with improved real power transfer using TCSC in 30 bus system

Secure operation and reliable utilisation of transmission lines is a challenging issue in deregulated power system. The scheduled power transactions are difficult due to the overloading of transmission lines in restructured power system as the electricity market has become more competitive. Due to congestion of transmission lines, the transfer of real power and the power system voltage profile are greatly affected in the power system. The aim of this research work is to increase the real power and the reactive power flowing in the lines of multibus system using thyristor controlled series compensator (TCSC). Real power transfer with reduced losses and improved voltage stability is an important factor in the present global scenario. This paper deals with the improvement of power flow in power transmission lines by series compensation device in 30 bus system with reduced congestion. The 30 bus system without and with thyristor controlled series compensation device (TCSC) is modelled and simulated and the results are presented. The simulation studies indicate a significant improvement in the real and the reactive power flow with the introduction of TCSC. The advantages of the proposed system include the smooth variations of the real and the reactive powers.

Применение многоуровневых инверторов напряжения в распределенных устройствах продольной компенсации

The operation principles of multilevel inverter circuits and methods for controlling them are considered. The operation of a multilevel circuit as part of a distributed transformer-based series compensation device is analyzed. The specific feature pertinent to the operation of a self-excited inverter within a distributed series compensation device is that it is loaded on the transformer connected in series into the power transmission line. In this case, the load is in fact a current transformer. Analytical expressions for calculating the circuit parameters are presented. The results of spectral modeling and simulation of the multilevel circuit in different modes of its operation are given. By using the spectral modeling, the currents and voltages of all power circuit components and their harmonic composition were estimated in the steady-state operation mode, and it has been shown that inductive injection is the heaviest mode of operation, because the inverter current reaches its maximum value in this mode. In using the multilevel circuit, additional requirements are posed to the control system, which, in addition to ensuring stable control of the output voltage, must also balance the voltages across the capacitors in the inverter arm. In selecting a storage capacitor and filter capacitor, it should be borne in mind that the maximum possible voltage across these components is determined not only by the necessary boost voltage, but also by the line current in the rectifier mode and can be significantly higher than the originally evaluated value. The obtained results can be used in designing distributed series compensation devices on the basis of an NPC inverter.

Optimal Allocation of Comprehensive Resources for Large-Scale Access of Electric Kiln to the Distribution Network

With the significant progress of the “coal to electricity” project, the electric kiln equipment began to be connected to the distribution network on a large scale, which caused power quality problems such as low voltage, high harmonic distortion rate, and high reactive power loss. This paper proposes a two-stage power grid comprehensive resource optimization configuration model. A multi-objective optimization solution based on the joint simulation platform of Matlab and OpenDSS is developed. The solution aims to control harmonics and optimize reactive power. In the first stage, a multi-objective optimization model is established to minimize the active network loss, voltage deviation, and equipment cost under the constraint conditions of voltage margin, power factor, and reactive power compensation capacity. Furthermore, the first stage uses a particle swarm optimization (PSO) algorithm to optimize the location and capacity of both series and parallel compensation devices in the distribution network. In the second stage, the optimal configuration model of the active power filter assumes the cost of the APF as the objective function and takes the harmonic voltage content rate, the total voltage distortion rate, and the allowable harmonic current as the constraint conditions. The proposed solution eliminates the harmonics by uniformly configuring active filters in the distribution network and centrally control harmonics at the system level. Finally, taking the IEEE33 distribution network as the object and considering the change of electric furnace permeability in the range of 20%–50%, the simulation results show that the proposed algorithm effectively reduces the distribution network’s loss, its harmonic content and significantly improve its voltage.

Aperiodic steady-state stability criterion of electric power system with controlled series compensation on 200 kV line

Currently there is a need to synchronize operation of the electric power system in the remote areas and increase of existing lines transmission capacity. The construction of new power transmission lines involves high economic expenditures. Well-known papers consider the issues of application of controlled series compensation devices only for long-distance power transmission lines with voltage of 500 kV and higher to increase the transmission capacity and the level of stability. The aim of the study is to increase the stability and the limit of the transmitted power when controlled series compensation devices are installed on 220 kV lines. It is necessary to develop a criterion of aperiodic steady-state stability of an electric power system with a 220 kV-controlled power transmission line. Methods of mathematical modeling of electric power system, the theory of long-distance power transmission lines and electromechanical transients, and methods of analyzing electric power system stability were used. A.M. Lyapunov’s first approximation method was used to develop a simplified mathematical model. We applied the developed software as a simulation tool. An analysis was carried out to study the influence of series compensation devices regulation coefficients on the aperiodic steady-state stability of the electric power system and the transmission capacity of 220 kV power transmission lines. A change in the modulus of voltage drop at the power transmission and the angle characteristics under the influence of the regulation coefficients of the series compensation device was revealed. A criterion of aperiodic steady-state stability has been developed for systems of this kind with controlled series compensation. It differs from traditional ones by considering the changes in the voltage drop in the power transmission and it allows more accurate estimation of the proximity to the stability threshold. An assessment of aperiodic steady-state stability according to the formulated criterion for an electric power system with a controlled series compensation device on a 220 kV line was obtained. The values of the control coefficients of the series compensation device have been determined. No violation of the steady-state stability occurs under the given values. The results can be used to solve the issues of increasing the transmission capacity of transmission lines to improve the stability of the system.

FACTS Devices Impact on Congestion Mitigation of Power System

The voltage magnitude and reactive power control of a large power system are computed on the basis of its dynamic voltage controllers, which may overcome the limitations of a conventional controller of the power system. The approach of the voltage controller is dynamic in nature and capable of controlling voltage of the bus to the specified level and eliminates such circumstances which may lead the system to become uncontrollable. The static series compensation devices are capable of providing additional flexibility in the operation of power transfer on transmission lines. The previously presented paper discussed multiple applications of FACTS devices either in series or shunt connected. The FACTS devices, i.e., TCSC and SSSC, are incorporated in IEEE-14 bus test system for the analysis of their performance in a relation of reactive power and voltage magnitude. The steady-state modelling of these devices has been carried out by deriving the static equations. The WLS technique is used for measuring system parameters on individual buses. The techniques help in reducing error and improving accuracy in measuring of system parameters. The weak buses on which the voltage profile is poor have been identified. The FACTS devices as mentioned above are located on these buses. The voltage profile on these buses improves remarkably. The reactive power variation on these buses has been computed and graphically plotted. The size of the FACTS devices and their allocation has been determined on the basis of voltage magnitude and reactive power required on those buses during loading conditions. The IEEE 14 bus test system is designed on MATLAB/SIMULINK environment.

Optimal Placement of TCSC for Congestion Management and Power Loss Reduction Using Multi-Objective Genetic Algorithm

Electricity demand has been growing due to the increase in the world population and higher energy usage per capita as compared to the past. As a result, various methods have been proposed to increase the efficiency of power systems in terms of mitigating congestion and minimizing power losses. Power grids operating limitations result in congestion that specifies the final capacity of the system, which decreases the conventional power capabilities between coverage areas. Flexible AC Transmission Systems (FACTS) can help to decrease flows in heavily loaded lines and lead to lines loadability improvements and cost reduction. In this paper, total power loss reduction and line congestion improvement are assessed by determining the optimal locations and compensation rates of Thyristor-Controlled Series Compensator (TCSC) devices using the Multi-Objective Genetic Algorithm (MOGA). The results of applying the proposed method on the IEEE 30-bus test system confirmed the efficiency of the proposed procedure. In addition, to check the performance, applicability, and effectiveness of the proposed method, different heuristic algorithms, such as the multi-objective Particle Swarm Optimization (PSO) algorithm, Differential Evolution (DE) algorithm, and Mixed-Integer Non-Linear Program (MINLP) technique, are used for comparison. The obtained results show the accuracy and fast convergence of the proposed method over the other heuristic techniques.

Influence of Series Compensation Degrees on Secondary Arc Current Characteristics under the Different Series Compensation Mode

AbstractThe high compensation degree series compensation has a broad development prospects in long distance and large-capacity UHV transmission lines. But it is generating secondary arc current contains low frequency components with high amplitude when the single-phase grounding fault occurs in the series compensated transmission line, which is not conducive to rapid arc extinguishing. To solve this problem, this paper based on the mechanism of generating secondary arc by series compensation transmission lines, and using ATP – EMTP electromagnetic transient program to establish the simulation model of UHV series compensation device. And the suppression effects of small resistance short connection fault series compensation and linkage bypass series compensation measures on secondary arc current and recovery voltage under different series compensation layout mode are studied respectively. The results show that the attenuation speed of the secondary arc current is related to the series compensation arrangement modes and the time when the series compensation device is short connected or bypassed. Series compensation device short connected or bypassed before circuit breaker tripping which can accelerate the arc extinction speed, and the suppression effect is better when the series compensated double platform segmentation layout is distributed on both sides of the line. The results can be used as a reference for the engineering design of UHV with large capacity and long distance and high compensation series compensation transmission lines.

Research of distance protection functioning of transmission line with series compensation device

Transmission line is one of the main elements of the power supply system. Line capacity can increase, when series compensation are used. Unfortunately, the use of these devices can lead to a failure of operation or to a false operation of the relay protection of the line itself. To analyse the operation of the relay protection of the compensated line, the RTDS software and hardware complex was selected.

Bi-Objective Optimization Model for Optimal Placement of Thyristor-Controlled Series Compensator Devices

Exposure to extreme weather conditions increases power systems’ vulnerability in front of high impact, low probability contingency occurrence. In the post-restructuring years, due to the increasing demand for energy, competition between electricity market players and increasing penetration of renewable resources, the provision of effective resiliency-based approaches has received more attention. In this paper, as the major contribution to current literature, a novel approach is proposed for resiliency improvement in a way that enables power system planners to manage several resilience metrics efficiently in a bi-objective optimization planning model simultaneously. For demonstration purposes, the proposed method is applied for optimal placement of the thyristor controlled series compensator (TCSC). Improvement of all considered resilience metrics regardless of their amount in a multi-criteria decision-making framework is novel in comparison to the other previous TCSC placement approaches. Without loss of generality, the developed resiliency improvement approach is applicable in any power system planning and operation problem. The simulation results on IEEE 30-bus and 118-bus test systems confirm the practicality and effectiveness of the developed approach. Simulation results show that by considering resilience metrics, the performance index, importance of curtailed consumers, congestion management cost, number of curtailed consumers, and amount of load loss are improved by 0.63%, 43.52%, 65.19%, 85.93%, and 85.94%, respectively.

An approach for long term economic operations of competitive power market by optimal combined scheduling of wind turbines and FACTS controllers

Wind farm integration with existing main electricity grid is very difficult due to the uncertainty of wind speed, which affects the balancing nature of electrical system. In current competitive power market, it is very challenging to maintain the quality of delivered power to the customers and also maximization of profit for delivered power after integration of such type of intermittent renewable energy sources. This paper presents an efficient optimization approach to achieve the maximum social welfare and profit of consumers as well as maximum profit of generation companies, by minimizing the adverse effect of imbalance cost which is the product of uncertain wind penetration. The optimal placement of Thyristor Controlled Series Compensator (TCSC) & Unified Power Flow Controller (UPFC) devices, with optimal wind generator placement has been incorporated in the proposed method. The real time data for actual and forecasted wind speed has been collected from different identified places of India. Modified IEEE 14 bus and modified IEEE 30 bus test systems are considered in this work for validating and analyzing the effectiveness of the proposed approach.

An optimal voltage stability enhancement in the power systems by locating optimal place with more contingency risk

The electrical components of a power system network take advantage to supply, transmission and service electrical power. Abnormal flow of voltage through the transmission lines might lead to big causes. Thyristor controlled series compensator (TCSC) devices are most frequently used device in the power to maintain the voltage stability. However, this device is costlier and cannot be fixed on every transmission line which would lead to more processing cost. Thus, the maintaining voltage stability of transmission lines with reduced production cost attracts a various researcher to find the novel approaches. In the existing system, to improve the stability of power system and minimize the losses by include the reactive power through TCSC device at applicable location by the algorithm of particle swarm optimization is available with the help of line stability index value. The PSO is constrained to poor exploitation problem which might generate inaccurate results. In the proposed research work, Biogeography Based Krill Herd (BBKH) method is used for optimal identification of TCSC's, STATCOM and UPFC size and location. Voltage collapse proximity indicator (VCPI) value is used in this work for the finding of the voltage instability measurement by finding the critical lines among the entire transmission lines. The proposed research effort is implemented in IEEE 39 test bus system using MATLAB software and verified, it furnishes improved outcome than other investigation methodologies.

An Optimal Voltage Stability Enhancement in the Power Systems by Locating Optimal Place with More Contingency Risk

The electrical components of a power system network take advantage to supply, transmission and service electrical power. Abnormal flow of voltage through the transmission lines might lead to big causes. Thyristor controlled series compensator (TCSC) devices are most frequently used device in the power to maintain the voltage stability. However, this device is costlier and cannot be fixed on every transmission line which would lead to more processing cost. Thus, the maintaining voltage stability of transmission lines with reduced production cost attracts a various researcher to find the novel approaches. In the existing system, to improve the stability of power system and minimize the losses by include the reactive power through TCSC device at applicable location by the algorithm of particle swarm optimization is available with the help of line stability index value. The PSO is constrained to poor exploitation problem which might generate inaccurate results. In the proposed research work, Biogeography Based Krill Herd (BBKH) method is used for optimal identification of TCSC's, STATCOM and UPFC size and location. Voltage collapse proximity indicator (VCPI) value is used in this work for the finding of the voltage instability measurement by finding the critical lines among the entire transmission lines. The proposed research effort is implemented in IEEE 39 test bus system using MATLAB software and verified, it furnishes improved outcome than other investigation methodologies.

Transmission Line Capacity Improvement Using Thyristor Controlled Series Compensation Device Considering Voltage Stability Analysis

In this paper, the interior point method (IPM) is applied to the optimal reactive power planning (ORPP) problem using the thyristor controlled series compensator (TCSC) device with consideration of voltage stability with handling the improvement of transmission line capacity in electrical network. To improve this case of study, two other objective functions are associated. The first is the angle deviation minimisation problem; it minimises the difference between the sending and receiving bus angles. And the second one is voltage deviation problem which aims to improve the system voltage profiles. The choice for these associate objective functions is defined by the most influence of bus angles and voltages to improve the system transmission line capacity. Also, the proposed algorithms satisfy various constraints, which are: power flow equations, generator voltage limits, switchable capacitor banks, transformer tap changer limits and transmission line limits. The fast voltage stability index (FVSI) is used to identify the critical lines to install the TCSC controllers. The methodology has been tested in the equivalent Algerian electrical power systems 114 bus. The simulation results show the effectiveness of the proposed approach for improving the reactive power planning problem.

High-Speed Decision Tree Based Series-Compensated Transmission Lines Protection Using Differential Phase Angle of Superimposed Current

This paper presents a decision tree based high-speed intelligent scheme for series-compensated transmission line protection using differential phase angle of superimposed current (DPASC). The conventional distance relaying scheme undergoes many shortcomings in transmission line protection in the presence of series compensation devices. The proposed scheme calculates the differential phase angle of current signals using full cycle discrete Fourier transform. The DPASC for each phase is used as an input to the data mining model known as decision tree (DT). The DT is used to generate thresholds to detect and classify the faults since determination of robust thresholds is an important challenge in protective relay engineering. The proposed method has been tested for different operating modes of transmission line in SIMIULINK/MATLAB software. Simulation results indicate that the proposed method is able to detect and classify the faults with acceptable accuracy, in less than half cycle.

Self-adaptiveness in particle swarm optimisation to enhance available transfer capability using thyristor-controlled series compensation (TCSC)

Available transfer capability (ATC) is one of the challenging criteria under the functioning of the deregulated power system. The high demand for improving ATC is generally met using flexible alternating current transmission system (FACTS) devices in the power system. However, it suffers from serious crisis during determination of the optimal location and compensation stage of FACTS. The present study uses thyristor-controlled series compensation (TCSC) devices in order to compensate for the limitation of FACTS. Further, a novel self-adapted particle swarm optimisation (SAPSO) algorithm is proposed in this study for enhancing ATC. Experiments are carried on three benchmark bus systems such as IEEE 24, IEEE 30 and IEEE 57. Performance and statistical analyses are carried out by comparing the proposed SAPSO with the conventional PSO. Eventually, the study proves the effectiveness of the proposed method in case of ATC enhancement.

Analysis on the Operation Strategy of the 220kV External Transmission Channel for the Nujiang Power Grid after the Installation of Series Compensation

In recent years, Nujiang Prefecture vigorously develop hydropower, the grid structure in the northwest of Yunnan Province is not perfect, which leads to the research and construction of the power grid lags behind the development of the hydropower. In 2015, the company in view of the nu river hydropower dilemma decided to change outside the nu river to send out a passage with series compensation device in order to improve the transmission capacity, the company to the main problems related to the system plan, but not too much in the region distribution network and detailed study. Nujiang power grid has unique structure and properties of the nujiang power grid after respectively, a whole rack respectively into two parts, namely power delivery channels, load power supply, the whole grid occurred fundamental changes, the original strategy of power network is not applicable, especially noteworthy is the main failure after network of independent operation problem, how to avoid the local series, emergency problem is more urgent, very tolerance test area power grid, this paper aims at the analysis of existing data, simulation, provide a reference for respectively after the operation for the stable operation of the power grid.

TCSC based automatic generation control of deregulated power system using quasi-oppositional harmony search algorithm

In present aspect, automatic generation control (AGC) of deregulated power system with thyristor controlled series compensator (TCSC) device is investigated. The objective is to discuss bilateral power transaction issue with the TCSC effect. A deregulated two-area power system model having two thermal units in each control area is considered for this act. A quasi-oppositional harmony search (QOHS) algorithm is being applied for the constrained optimization problem. Three cases, commonly studied in deregulation, are discussed for the effectiveness of the proposed technique. Further, sensitivity analysis is studied by varying the test system parameters up to ±25% from their rated values. The obtained simulation plots are analytically discussed with the calculation of oscillatory modes, transient details and the studied performance indices. Sugeno fuzzy logic control technique is also investigated to the studied test system. The simulation results show that the proposed QOHS based TCSC controller is quite effective in deregulated environment.

Model Predictive Load Frequency Control of two-area Interconnected Time Delay Power System with TCSC

In order to reduce the influence of non-linear constraint and time delay on load frequency control of interconnected power system, this paper, based on Model Predictive Control (MPC), designed a load frequency control scheme for two-area interconnected power system with TCSC device. First, considering the Generation Rate Constraint (GRC) and time delay, this paper builds the dynamics model of two-area interconnected power system with Thyristor Controlled Series Compensation device (TCSC). Then the whole system is decomposed into two subsystems. And each subsystem has its own local area MPC controller. Second, collaborative control is implemented by integrating the control information (measurement value, predictive value, etc.) of subsystems’ MPC controllers into the local control goal. In the end, under consideration of physical constraints, the Matlab simulation is conducted. The calculation results showed that the MPC strategy has better dynamic performance and robustness compared to the traditional PI control.

A Series Compensation Device for the LV Power Quality Improvement

A Series Compensation Device for the LV Power Quality Improvement