Series Compensation Devices Research Articles

Wind conversion systems effects on power grid and ability of thyristor controlled series capacitor and static synchronous series compensator devices for dynamic performance enhancing

Wind conversion systems effects on power grid and ability of thyristor controlled series capacitor and static synchronous series compensator devices for dynamic performance enhancing

Сравнение характеристик линий высокого и сверхвысокого напряжений при выборе параметров управляемого устройства продольной компенсации

The use of series compensation devices leads to an increase of the transmission line capacity. However, it also increases the risk of an oscillatory violation of the stability of the electric power system. Cumulative hunting and self-excitation of the system is observed in the systems with controlled series compensation devices with a high degree of capacitive compensation. It is known that automatic excitation control of generators partially eliminates the negative effect of series capacitive compensation on oscillatory stability. Therefore, when choosing the tuning parameters of controlled devices, it is necessary to consider their combined effect on the system modes. The developed methods to study steady-state stability make it possible to analyze the modes of power systems with controlled power transmission of various voltage levels. Thus, it is advisable to conduct a comparative analysis of the influence of the adjustable parameters of the series compensation device on the steady-state stability of systems of various voltage levels, considering synchronous generators automatic excitation control. Methods of mathematical modeling of the electric power system, the theory of long-distance power lines and electromechanical transients, methods of analyzing the stability of electric power systems are used. The original software in the C ++ programming language has been used as a modeling tool. The choice of controlled series compensation device and the automatic excitation control regulation laws parameters is made, provided that steady-state stability is maintained. The stability regions of the studied electric power-engineering system are constructed depending on the tuning parameters of the considered devices of various voltage levels. A comparative analysis of the characteristics of the modes of high and extra-high voltage lines has been carried out. The regulation coefficients values of controlled series compensation device and automatic excitation of generators have been determined, under which there is no violation of oscillatory stability for different voltage levels. The conducted comparative analysis of the characteristics of high and extra-high voltage power lines demonstrates the need to consider the power transmission rated voltage when comprehensively selecting the tuning parameters of the controlled series compensation device and the automatic excitation control regulator.

Integrated transmission expansion planning incorporating fault current limiting devices and thyristor-controlled series compensation using meta-heuristic optimization techniques

Transmission expansion planning (TEP) is a vital process of ensuring power systems' reliable and efficient operation. The optimization of TEP is a complex challenge, necessitating the application of mathematical programming techniques and meta-heuristics. However, selecting the right optimization algorithm is crucial, as each algorithm has its strengths and limitations. Therefore, testing new optimization algorithms is essential to enhance the toolbox of methods. This paper presents a comprehensive study on the application of ten recent meta-heuristic algorithms for solving the TEP problem across three distinct power networks varying in scale. The ten meta-heuristic algorithms considered in this study include Sinh Cosh Optimizer, Walrus Optimizer, Snow Geese Algorithm, Triangulation Topology Aggregation Optimizer, Electric Eel Foraging Optimization, Kepler Optimization Algorithm (KOA), Dung Beetle Optimizer, Sea-Horse Optimizer, Special Relativity Search, and White Shark Optimizer (WSO). Three TEP models incorporating fault current limiters and thyristor-controlled series compensation devices are utilized to evaluate the performance of the meta-heuristic algorithms, each representing a different scale and complexity level. Factors such as convergence speed, solution quality, and scalability are considered in evaluating the algorithms’ performance. The results demonstrated that KOA achieved the best performance across all tested systems in terms of solution quality. KOA’s average value was 6.8% lower than the second-best algorithm in some case studies. Additionally, the results indicated that WSO required approximately 2–3 times less time than the other algorithms. However, despite WSO’s rapid convergence, its average solution value was comparatively higher than that of some other algorithms. In TEP, prioritizing solution quality is paramount over algorithm speed.

Enhancing Loadability of Transmission Lines Using Static Synchronous Series Compensator Devices: A Case Study of the Syrian Network

Enhancing Loadability of Transmission Lines Using Static Synchronous Series Compensator Devices: A Case Study of the Syrian Network

A SSSC optimal configuration method to enhance available transfer capability considering multi‐wind farm access

AbstractIn the context of electricity market, the heavy load of some inter‐provincial and intra‐provincial lines limits available transfer capability (ATC). As a series compensation device, static synchronous series compensator (SSSC) can reallocate the power flow of adjacent lines. In order to maximize the inter‐regional ATC, a two‐stage optimal SSSC allocation method considering the uncertainty and correlation of multi‐wind farm is proposed. Firstly, the initial wind power scenarios are generated based on latin hypercube sampling (LHS) and reduced by the improved iterative self‐organizing data analysis techniques algorithm (I‐ISODATA). Then, a multi‐objective optimization model is constructed with the maximum expected power flow transfer entropy (PFTE) and minimum expected SSSC investment cost in all typical wind power scenarios, and non‐dominated sorting genetic algorithm‐II (NSGA‐II) method is used to determine the location of SSSC. In addition, based on the reduced wind power scenarios, the ATC calculation model containing SSSC is constructed, and the modern interior point method is used to determine the control parameters and configuration capacity of SSSC. Finally, based on the improved IEEE39 and IEEE118 node systems, case study proves that the proposed model can determine the optimal SSSC configuration scheme and significantly improves the ATC.

Parallel Impulse Current Shunt Performance of Multiple MOVs for 500 kV Series Compensation

As an important component of the transmission line series compensation device, MOVs have the strong nonlinear characteristics to limit the overvoltage caused by line fault and protect the capacitor banks in 500kV lines. We studied the parallel impulse current shunt performance of multiple MOVs and the influence of the mixed-use of new MOVs with served MOVs for different numbers of MOVs on impulse shunt performance. We conducted 500 kV MOV parallel impulse shunt tests under three conditions of 9-served+2-new, 11-served and 9-served. We found that when MOVs with different V-I characteristics are connected in parallel, the impulse current action characteristics of a single MOV will not be affected. When the number of MOVs in parallel is changed from 11 to 9, the dispersion of impulse current does not change significantly. When two served MOVs are replaced with two new MOVs (with a 1% increase in DC U <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2mA</sub> ), the average dispersion of impulse current increases by 2.81%, and the average maximum deviation increases by 5.93%. If the margin is sufficient when MOVs in the whole group are damaged, they can be replaced with matched new MOVs.

Squirrel search algorithm based intelligent controller for interconnected power system

ABSTRACT In this paper, a novel controller, namely fractional order fuzzy proportional-integral-derivative (FOFPID) has been proposed for the dual area power system of hydro-thermal-gas units (DAHTG). The squirrel search algorithm (SSA) is implemented to achieve the optimal values of the controller tuning parameters. Further, various non-linearity constraints, such as governor dead band (GDB), generation rate constraint (GRC) and communication time delays (CTDs) have also been considered to test the effectiveness of the proposed controller in a real-time environment. The step load of 10% is provided as the disturbance under the regulation. In addition, the coordinated strategy of a static synchronous series compensator (SSSC) device and superconducting magnetic energy storage (SMES) is employed in the proposed system to enhance the system’s performance. Further, the accuracy, effectiveness and robustness of the proposed controller are revealed through the comparative analysis with classical PID and traditional fuzzy PID controllers. Furthermore, presented controller efficacy is revealed with the other recently reported control techniques by implementing it on the two-area thermal system with GDB. The comparative analysis shows the better performance of the proposed controller than these two. Finally, the sensitivity analysis is performed to check the controller robustness.

Предел передаваемой мощности управляемой линии электропередачи высокого напряжения для режимов на границе статической устойчивости

The use of series compensation devices is one of the methods to increase the capacity of a power transmission line. In addition, the use of controlled series compensation devices affects the steady-state stability of the electric power system. It is also widely known that automatic excitation control of generators has a positive effect on the stability of the system. Thus, it is reasonable to analyze the influence of the adjustable parameters of the controlled series compensation device on the line capacity when considering modes at the boundaries of the stability regions, taking into account automatic excitation controllers on synchronous generators of the power plant. Methods of mathematical modeling of the electric power system, the theory of long-distance power lines and electromechanical transients, methods of analyzing the stability of electric power systems are used. The original software in the C ++ programming language is used as a modeling tool. The authors have selected the regulation laws parameters of controlled series compensation device and automatic excitation controller, provided that steady-state stability is maintained. The stability regions of the electric power-engineering system under study are constructed depending on the tuning parameters of the considered devices. A technique is proposed to select the coefficients of complex regulation of the devices to increase the capacity of a high-voltage power transmission line. The proposed method of the complex selection of regulation coefficients of controlled devices provides the possibility of obtaining their optimal values in a controlled electric power system to ensure stability.

Current state of the problems of functioning of relay protection and automation complexes used in an active adaptive network

THE PURPOSE. To analyze the influence of series compensation devices on the operating modes of power transmission lines. To identify problems of functioning of relay protection and automation complexes when they are used on power transmission lines with a series compensation device.METHODS. The analysis of literature data and data of international information exchange is carried out.RESULTS. The study describes the relevance of the topic, considers the main elements of an electric power system with an active adaptive network; reveals the current state of affairs on the use of elements of an active adaptive network in the Unified Energy System of Russia, as well as prospects for further implementation of these elements in the Unified Energy System of the Russian Federation. The study shows the scope of application of series compensation devices with the inductive resistance for their placement on power transmission lines, and the optimal distance between series compensation devices, as well as the optimal parameters of the capacitive resistance relative to the resistance of the network. The study discloses problems of functioning of various types of relay protection and automation on power transmission lines with a series compensation device.CONCLUSION. The use of a reactance series compensation device on the line causes problems of functioning for all types of relay protection and automation devices, namely: current, remote, differential and reclosing automation. At the moment, for the listed types and kinds of protection, there are scientific developments to solve these problems with their inherent advantages and disadvantages. The study indicates the most acute disadvantages of the differential relay protection.

Research on the Torsional Vibration Response Characteristics of Parallel Operation Steam Turbine Generator Unit Shafting

With the continuous increase of unit capacity and the widespread application of series compensation devices in power transmission systems, the risk of coupling oscillation between units and power grids and between units has increased significantly, which seriously endangers the safe operation of units and power grids. In this paper, the torsional vibration response of each unit after grid failure is calculated by establishing a lumped mass model of the shafting torsional vibration of the parallel unit. The effects of fault type, series compensation degree and fault location on the torsional vibration of parallel unit shafting are studied. The results show that the three-phase short-circuit fault in the grid has a greater impact on the unit; the influence of series compensation degree on the torsional vibration of the shaft system decreases first and then increases; when the transmission line fails, it will produce a certain torsional vibration excitation effect on the shafting of all units; when a short-circuit fault occurs at the outlet of a generator, the torsional vibration excitation of the unit is the largest, but it will also produce a certain degree of torsional vibration excitation to other units in the same network.

Fast decoupled state estimation including thyristor controlled series compensator devices

This paper extends the weighted-least-square state estimation (WLS-SE) formulation to enable the solution of networks with embedded thyristor-controlled series compensation (TCSC). In the proposed methodology, the TCSCs reactances are treated as new state variables along with the complex voltage at the network nodes. Information regarding the specified active power flow through transmission lines connected to TCSCs and net power injection at their connecting nodes are strategically modeled as new active and reactive pseudo-measurements to be included into both: the linear and the fast-decoupled WLS-SE problem. Applications of the proposed extension in connection with the exact solution of a TCSC embedded power flow algorithm are presented and discussed. The IEEE 14- and 118-bus test systems are employed to illustrate and evaluate the proposed approach. The results point out that the new tool is effective to accurately estimate the system states and the control parameters of the TCSCs under distinct operating conditions.

A Single-Circuit Extra-High Voltage Line of Increased Transmission Capacity

Conventional single-circuit EHV AC lines, widely used around the world, feature an essential drawback: in the case of most probable single-phase sustained failures, the line is fully disconnected. An advanced single-circuit EHV line is proposed, one phase of which is made as two semi-phases operating in parallel to each other. In emergency modes, one of these semi-phases is used as a backup phase, and two usual phases are equipped in the line middle part with series compensation devices for balancing the line operation mode. An algorithm for calculating normal operation modes has been developed. Taking the example of an advanced 500 kV line, the ratio between the transmission capacities of the proposed line and a conventional single-circuit line is shown. A scheme is proposed, with which it becomes possible, in the case of a sustained damage to one of the semi-phases or in case of damage to one of the phases, to switch over for operation in the post-emergency mode with the possibility of transmitting at least 50% of the power of the initial maximum operation mode. A technical and economic comparison of a conventional double-circuit and the advanced single-circuit lines was carried out.

An Enhanced Intelligent Facts Device for Reduction of Losses on Power Lines

In this research, an enhanced intelligent FACTS device for reduction of losses on power lines using intelligent Static Synchronous Series Compensator (SSSC) devices for Nigerian 330kv network has been presented. The findings showed total real power losses of 127.9131MW before network compensation, with transmission lines accounting for 125.7MW and producing stations accounting for 2.2131MW. After compensation using Static Synchronous Series Compensator (SSSC), the total Real power losses were reduces to 104.53MW, while the total Reactive losses (MVar) reduced to 26.87MVar. The research concludes that the injection of reactive power by Static Synchronous Series Compensator (SSSC) devices compensates for the drop in voltage, leading to improvement in voltage and reduces power losses for the network.

Analysis of influence of controlled high voltage line and automatic excitation control generators on oscillatory steady-state stability of electric-power system

According to the rules of installation of electricity-generating equipment, synchronous machines (generators, compensators, electric motors) must be equipped with automatic excitation control devices. Their application has a positive effect on the stability indicators and electrical power-engineering system modes. Currently, the development of industry and an increase in the number of consumers require transmission capacity growth of existing 220 kV power transmission lines. The use of controlled series compensation devices can significantly increase the transmission capacity of a power transmission line, however, there is a problem of stable operation of the electric power-engineering system. To choose the methods for control parameters of automatic excitation control and controlled series compensation device, it is advisable to analyze the oscillatory steady-state stability of the electric power-engineering system that contain a controlled 220 kV power transmission line when regulating the excitation of its generators. Methods of mathematical modeling of the electric power system, the theory of long-distance power lines and electromechanical transients, methods of analyzing the stability of electric power systems are used. The original software in the C++ programming language has been used as a modeling tool. The authors have analyzed the influence of controlled series compensation of high voltage transmission line and generators of automatic excitation control on oscillatory steady-state stability of electric power system. The parameters value of regulation of the controlled series compensation device and the automatic excitation control are determined, considering restrictions while maintaining the positive influence of these devices. Zones of stability of the examined electric power-engineering system are formed depending on setup variable of the devices under consideration. The obtained results can be used to enhance oscillatory steady-state stability of electric power system with controlled series compensation device and automatic excitation control systems.

Improved harmony search optimization-based TCSC placement for loss minimization

Placement of thyristor-controlled series compensator (TCSC) devices at appropriate lines reduces the net transmission loss (NTL) through injecting suitable series voltage in the transmission lines. The classical approaches for placing TCSCs in the power network may not provide optimal solution and face intricacies in solving the problem with multifarious constraints and vehemently place all the allotted TCSCs in the network. This paper presents a method employing improved harmony search optimization (MHSO), an evolutionary algorithm, for solving TCSC problem (TCSCP) and places the vital number of SVCs from the allotted ones. This paper presents the solution of TCSCP problem of 14, 30 and 57 bus systems and compares the performances in various aspects with existing TCSCP methods.

Augmented Power Dispatch for Resilient Operation through Controllable Series Compensation and N-1-1 Contingency Assessment

Research on enhancing power system resilience against extreme events is attracting significant attention and becoming a top global agenda. In this paper, a preventive augmented power dispatch model is proposed to provide a resilient operation. In the proposed model, a new N-1-1 security criterion is proposed to select disruptive N-1-1 contingency cases that might trigger cascading blackouts, and an iterative contingency assessment process based on the line outage distribution factor is proposed to deal with security constraints. In terms of optimization objectives, two objectives related to power flow on the transmission line are considered to reduce the possibility of overload outages. Controllable series compensation devices are also considered in the model to improve the power flow distribution. Case studies conducted on the modified IEEE 30-bus, 118-bus and Polish 2382-bus systems show that the power flow solution of the proposed power dispatch model can avoid some branches from undertaking excessively heavy loads, especially lines forecasted to be affected by extreme events. The results of blackout simulations through a hidden failure cascading outage simulation model show that the average power losses of the proposed model are reduced by around 40% in some cases as compared to the classical economic dispatch model.

Research about a fast identification method for intermittent single Sub-synchronous Resonance phenomenon in large scale doubly-fed wind farm

In this paper, a synchronous resonance (SSR) phenomenon caused by a large scale doubly-fed wind farm group after putting in series compensation device is analysed. By analysing the changing trends of the indicators during period of SSR phenomenon, 11 power quality indicators are chosen for calculated, then divided all the 11 indicators into 3 source data and 8 preliminary stage operational data by the observability of value. After divided the two kinds of data, a Pearson correlation coefficient between this two kind data was calculated to judge the relationship of them, and the characteristic indexes with stronger correlation during the resonance period were analysed. The maximum value of the above 8 characteristic indexes in the normal power generation process is used as the basic data for comparison, so as to realize the rapid and accurate judgement of the SSR moment. In the process of SSR judgement, the method has the characteristics of faster speed and simple determination, and it does not need to reform the existing power quality online monitoring device, and can realize real-time analysis and judgement of SSR phenomenon only by increasing extraction of the existing data function from the monitoring system. Finally, by testing data of two actual SSR events, the characteristic index determination method proposed in this paper is analysed and verified, and the feasibility of this method is proved.

Adaptive Configuration Method of Low-Frequency Electromechanical Sampling Information in Building Electrical System

In order to enhance the reliability of the electrical systems in low frequency, an adaptive configuration method of low-frequency electromechanical sampling information based on thyristor controlled series compensation (TCSC) is designed. The electrical system is simplified to a linear invariant system, and a stochastic subspace identification (SSI) method is established by using the singular value decomposition principle to collect low-frequency electromechanical sampling information. The reference channel technology is introduced to design the reference channel covariance matrix to judge whether low-frequency information is generated and improve the efficiency of sampling information acquisition. The architecture and working principle of the controllable series compensation device are analyzed, and the test signal method is used to evaluate the low-frequency modes and the information required by the device among the electrical system regions of buildings. The alternative input signals are selected by comparing different input signal residue ratios. The TCSC device parameters are adjusted by the compensation residue phase method, so as to realize the adaptive configuration of different low-frequency electromechanical sampling information and ensure the stable operation of the electrical system. The experimental results show that the proposed configuration scheme can effectively improve the damping ratio of the system and has an excellent effect on suppressing the continuous oscillation under a low-frequency fault.

Small Signal Stability Assessment in Presence of SSSC for a Power System Under Fault Disturbance

The use of FACTS controllers in power grids has resulted in the improvement of stability issues related to the power systems. When the FACTS controllers are used to damp out the power systems oscillation, there series controller inverter like static synchronous series compensator (SSSC) device are the most suitable to resolve the issue. In this paper, importance is given on the optimal operation of the SSSC and to the maintenance of the small signal stability of the system. Here the main focus is to check the system response to stability after the use of SSSC device.

Optimal coordination of thyristor controlled series compensation and transmission expansion planning: Distributionally robust optimization approach

This paper proposes a distributionally robust optimization method for assessing economic benefits of transmission expansions with thyristor controlled series compensation devices. To accommodate the uncertainty of wind generations and electrical vehicle loads, a distributionally robust optimization method is proposed to use historical data instead of predefined distribution probabilities. In the proposed framework, firstly, a confidence set for unknown distributions are constructed based on the historical data. Then, based on worst-case distributions within a constructed confidence set, the optimal results of transmission expansion planning and allocation of thyristor controlled series compensation device are obtained. In order to take advantage of the flexible alternative current transmission devices (FACTS) in both economic and technical considerations, the optimal allocation of thyristor controlled series compensation is integrated into the transmission expansion planning. This requires AC-based transmission expansion planning model. AC power flow suffers from high computational complexity. To tackle this issue, the linearized AC power flow model is utilized. Furthermore, to solve the optimization problem, the combined technique including Bender's decomposition and cut-and-column are utilized. The numerical results on the Garver 6-bus and IEEE 118-bus systems demonstrate the effectiveness of the proposed method in comparison with scenario-based stochastic and robust optimization methods. Besides, the impacts of the thyristor controlled series compensation on total cost reduction has been investigated.