Shunt Reactor Research Articles

Gas Production Characteristics of UHV Oil immersed Shunt Reactor with Vibration Defects

The special multi-air gap structure of Ultra high voltage (UHV) oil-immersed shunt reactor determines that its magnetic leakage is far greater than that of a power transformer of the same voltage level, and it is more prone to vibration and other problems. Overheating and suspended discharge caused by vibration are important sources of excessive gas production in UHV shunt reactors. In this paper, the source of gas production under reactor vibration is analyzed, and a reactor defect simulation gas production platform is built. Using oil chromatography analysis, partial discharge detection, and other means, the gas production characteristics, discharge characteristics and insulation degradation characteristics of typical defects such as suspended discharge and partial overheating under vibration have been experimentally studied. Then, the correlation analysis model between the vibration type, intensity, overheating degree, and the reactor performance change was established. Finally, the gas production and discharge characteristics of the reactor under different defect types were obtained. Besides, gas production characteristics under vibration with 50 Hz, 100 Hz, and 150 Hz were carried out, and it was found that the gas will continue to increase with the increase of vibration frequency, and the growth has been stabilized after exceeding 100 Hz. The relevant research results of this paper can provide technical support for the application of UHV oil-immersed shunt reactor state assessment and diagnosis, and improve the level of equipment operation and maintenance.

A 3D model of three phase shunt reactors by using a finite element technique with coupling to global quantities

The finite element technique is used widely for researchers and manufacturers to design and simulate electrical systems in general and electrical machines such as shunt reactors (SRs) and transformers in particular. Many papers have recently applied several methods to analyze magnetic fields, copper losses and joule power losses in the shunt reactors (SRs). In this research, the finite element technique with coupling to global quantities is proposed to investigate the voltage and current distributions in the windings, and compute the distribution of magnetic field in the air gap and along the air core of the SR, as well as copper and core losses. The developed method is directly applied to the practical SR of 91 MVAr and a rated voltage of 500 kV. The finite element method (FEM)-simulated results are validated with experimental results to ensure accuracy and reliability. This facilitate designing the reactor.

An investigation of distance protection function applied for shunt reactors

This article investigates the use of the distance function to protect shunt reactors. For this purpose, mho phase comparator is assessed. To carry out a comparative evaluation, the distance function performance was further compared with the differential function performance. Moreover, the Alternative Transit Program (ATP) was applied to model an electrical system, in which the reactor is subjected to different faults, including phase-to-phase, phase-to-ground, turn-to-ground and turn-to-turn faults. The performance of the evaluated distance function was also investigated against the number of turns involved and the leakage factor. From the results obtained, it is suggested the joint use of the distance function with the differential protection, because if the differential function does not operate, distance function would guarantee the operation for internal faults, including turn-to-ground and turn-to-turn faults, increasing reliability of protection scheme for shunt reactors. Also, the present study may serve as a guide for further studies, for example, that evaluate the use of distance function to protect iron-core reactors.

Моделирование режима одностороннего включения линии электропередачи сверхвысокого напряжения с применением устройства синхронизации моментов включения контактов фаз выключателя

Simulating the switching on of an overhead power transmission line (PTL) of ultra-high voltage in a dead-end mode, containing a significant aperiodic current component, both from the switch control key and in the three-phase automatic reclosing (TARC) cycle, is performed using the MATLAB software package. The aim of modelling is to search and find the optimal modes of electrical transmission operation in terms of admitting the values of the aperiodic current component and assessing possible values of overvoltages in the phases of power transmission lines. The possibility of using phase-by-phase control of a high-voltage circuit breaker, which ensures closing the power contacts of the circuit breaker phase at the moment of the maximum value of the instantaneous voltage on these contacts, is checked as a measure that can significantly reduce the influence of the aperiodic current component on the possibility of damaging switching equipment and developing an emergency situation in the power system. The results obtained can be used to practically eliminate the influence of the aperiodic current component in all possible modes (dead-end mode of an overhead line (OL), in an unsuccessful automatic reclosing cycle (ARC) for all types of short circuits on a high-voltage power line) with shunt reactors put into operation and without putting them into operation.

Adaptive single-phase auto-reclosing scheme based on the moving average filter-quadrature signal generator for transmission lines with shunt reactors

An adaptive single-phase auto-reclosing method based on the moving average filter (MAF)-quadrature signal generator (QSG) is developed to determine secondary arc extinction time for high-voltage transmission lines with shunt reactors. Firstly, the difference between permanent and transient faults is derived and analyzed by the equivalent circuit model. Then, MAF-QSG is utilized to extract these features from the fault voltage. During the second arc period, for transient fault, the fundamental component and subharmonic component with around 50 Hz are reserved by MAF-QSG; however, in the case of permanent fault, only the fundamental component is retained. Finally, the identification index and its threshold are designed above the extraction fault features. The performance of the proposed method is evaluated by simulation and field data studies, accounting for different transmission line compensation levels, transition resistances, and fault location conditions.

Magnetic circuit decomposition model and novel inner‐turn fault protection scheme for shunt reactor with auxiliary windings

AbstractShunt reactor with auxiliary windings (SRAW) can compensate inductive reactive power for long‐distance transmission lines and supply steady power for low‐voltage devices on offshore platforms. The operation characteristics of SRAW can be commonly described by the air‐core transformer equivalent model. However, this model can only make an approximate simulation of the external characteristics of SRAW, and cannot reflect the actual electrical features inside the SRAW. To solve this problem, the authors propose a three‐segment magnetic circuit equivalent model (TMCEM) of SRAW based on the magnetic circuit decomposition method. This model can accurately describe the coupling relationship inside SRAW and can be used for the analysis of internal fault characteristics. Furthermore, through the fault analysis utilizing TMCEM, a novel protection scheme of SRAW based on virtual magnetizing differential current is proposed for the detection of the inner‐turn fault in SRAW. This protection scheme has high sensitivity and can effectively identify the inner‐turn faults without measuring voltages. By testing the physical model of SRAW, the effectiveness of the TMCEM and the proposed protection scheme against inner‐turn fault has been confirmed.

Analysis and treatment of oil chromatography of a 1000kV high voltage parallel reactor

In this paper, the author combined with gas chromatography to a 1000kV high voltage shunt reactor oil chromatography anomaly analysis, preliminary theoretical analysis conclusion, then in the maintenance process through the equipment breakdown and the fault cause, verify the correctness of the theoretical analysis, for the next step of equipment manufacturers equipment manufacturing and process control provides advice.

압축구조 개선을 통한 분로리액터의 소음 저감에 관한 연구

Recently, with the development of the city center around the substation, complaints about noise are increasing. Shunt reactors are a major source of noise in substations. To reduce the noise of the shunt reactor, research on the magnetic circuit and structural design for optimizing the compression distribution are important. In this paper, the magnetic flux distribution and compression distribution of the magnetic element were calculated using a finite element analysis program, and the reduction effect was analyzed by measuring the noise. Introducing a study that improved the distribution of magnetic flux by applying a magnetic flux control panel to the vibration caused by the magnetomotive force generated from the magnetic element, and reduced noise by changing the shape of the compression structure.

Study on the secondary current characteristics of transmission lines coupling arc dynamics model with Mayr resistance model

In high-voltage transmission lines, secondary arcs severely affect the stability of power systems. However, there has been no research to combine transmission line model with time-varying resistance secondary arc. In this study, the improved arc dynamics model, the Mayr resistance model, and the transmission line system were combined in the simulation model to investigate the influence of the compensation reactor, line length, and short-circuit fault location on the characteristics of secondary arc current. The results revealed that the inhibitory effect of shunt reactors was the best at the midpoint between the fault point and the end of transmission line. When the series reactance satisfied a certain value, the short-circuit current was considerably suppressed with only a slight increase in the secondary current. The lower resistance along the line and longer transmission lines accelerated the secondary arc extinction rapidly. The location of the short-circuit fault had a limited effect on secondary arc extinction. The arc extinction time fluctuated within a small range with the changes in the location of the short-circuit fault. The results of the study can provide a reference for suppressing secondary arc currents.

Research on reactive power and voltage coordinated control of intelligent distributed network

with the continuous expansion of the scale of distributed new energy grid-connected power generation in the distribution network and the continuous improvement of penetration rate, the problem of distribution network voltage out of limit caused by distributed new energy grid connected can not be ignored. This paper analyzes the basic principle of voltage out of limit caused by the connection of distributed new energy sources to the distribution network,and analyzes the factors affecting the reactive power and voltage of the active distribution network with distributed new energy sources through BPA simulation, The compensation effects of the distributed series reactor and distributed shunt reactor are compared.

Three-phase adaptive reclosure technology for half-wavelength transmission lines using residual voltage frequency difference to identify fault existence

• The single-phase reclosing technique should not be used in half-wavelength transmission systems. • The residual voltage of half wavelength transmission system can be used to determine the existence of faults. • The frequency difference of residual voltage can be used to determine the existence of faults. • We propose a complete and feasible three-phase adaptive reclosure scheme for half wavelength transmission system. UHV AC transmission lines use adaptive reclosure technology not only to avoid reclosing in the permanent faults, but also effectively prevent the emergence of reclosing overvoltage, adaptive reclosure is of great significance, and its technical principle is based on the study and judgment of the existence of the fault. The reactive power of half-wavelength transmission lines along the line was self-balanced, no shunt reactor equipment, there is no "beat frequency" phenomenon, and very little information is available after the three-phase trip. In this paper, we analyze the fault traveling wave's frequency characteristics and identify the fault's characteristics based on the residual voltage frequency difference of the line after the three-phase trip. After the disappearance of the line fault, the stable frequency difference obtained by CVT reflects the entire length of the line, which is not affected by the system boundary conditions and can complete the reliable identification of the disappearance of the line fault. The two-terminal criterion is given for the short-line dead zone problem, and then a three-phase adaptive reclosure scheme for half-wavelength transmission lines based on the frequency difference to identify fault disappearance is proposed. Extensive RTDS digital-analog hybrid tests show that the method is correct and robust.

Evaluation and implementation of HV dry-type shunt reactors into a 420 kV transmission grid

Evaluation and implementation of HV dry-type shunt reactors into a 420 kV transmission grid

420 kV shunt reactors for reactive power compensation explaining the trends favoring air-core dry-type technology

420 kV shunt reactors for reactive power compensation explaining the trends favoring air-core dry-type technology

Optimization-Based Mitigation Techniques of the Temporary Overvoltage in Large Offshore Wind Farm

Overvoltage transient is the major danger facing large offshore wind farms, as it may lead to a complete failure of the system components. A 150 MW offshore wind farm was modeled using the ATP-EMTP package to analyze the effect of the temporary overvoltage resulting from de-energization conditions, and the ferro resonance phenomenon resulting from the asymmetric opening of circuit breaker pole(s). The results showed that the best scenario to shut down such a system from the grid with minimum values of temporary overvoltage is to disconnect it, feeder, by a feeder. The stuck of one or more poles during the opening operation of the circuit breaker is a dangerous phenomenon, as it induces a high overvoltage value, which lasts for a long time causing more electric stress on the sensitive components of the system. The use of the Pre-Insertion Resistor PIR was recommended as a mitigation technique for the temporary overvoltage in large offshore wind farms, as it proves a significant reduction in the overvoltage values reaches to 79.44 % compared to surge arrester and shunt reactor which reduce the over voltage by 68.33%, 66.29% respectively. The genetic algorithm was used to find the optimum value of the PIR and shunt reactor that leads to the minimum TOV. The optimum value of PIR which was recorded is equal to 57.352 Ohm, which leads to more reduction in the overvoltage value by 9.67%. Also, the optimum values of the resistor and inductor of the shunt reactor were found to be 11.238 Ohms and 37.246 mH which leads to more reduction in the overvoltage value by 21.97% compared to the reduction without optimization.

A MIQP Approach Based on Demand Response in Distribution Networks to Improve the Multi-Objective Function in the Presence of Renewable Energy Resources and Batteries to the Subway Systems

The increasing expansion of devices such as electric vehicle charging stations, renewable energy resources, and electric subways, will cause an imbalance between load and production in the distribution network, which will lead to an increase in power losses, a decrease or increase in voltage and ultimately impose more costs on the independent system operator (ISO). In this paper, we have presented a mixed integer quadratic programming (MIQP) optimization model to improve the distribution network performance in the presence of these devices. The proposed model is a mixed integer model including demand side management modeling, energy storage system, battery to subway (B2S) system, optimal control of on-load tap changer (OLTC), step voltage regulator (SVR), fossil generation resources, renewable energy and capacitors, and shunt reactors. The considered multi-objective function is a scenario-based stochastic model, which accurately models the uncertainties in renewable energy resources. Paying attention to the nature of the proposed model will guarantee globally optimal solutions. The proposed model runs on the standard network of 33 buses, and the simulation results guarantee the optimal and accurate performance of the proposed model. The simulation results demonstrate that the outage of three distributed generation units from the network causes an average increase of 55% in energy losses, and the outage of three renewable units leads to an increase in emissions of about 40%. Another point received from the results illustrated that with the implementation of the proposed model under any load level of the network, as well as the outage of fossil and renewable distributed generation (DG) resources, no load shedding will occur in the network during the 24 hours. Finally, due to the short execution run time, the proposed model can be used for real and online grids.

An Ultrahigh Voltage Shunt Reactor Acoustic Signal Separation Method Based on Masking Beamforming and Underdetermined Blind Source Separation

There are many types of acoustic sources in the ultrahigh voltage (UHV) substation. The acoustic signals of UHV shunt reactors obtained by direct measurement include many other phase reactor acoustic signals that are very similar to the subjected reactors in frequency domain characteristics, as well as cooling fans and random noise. An UHV shunt reactor acoustic signal separation method based on beamforming and undetermined blind source separation was proposed. In this method, the existing beamforming is improved to masking beamforming, which can separate those acoustic components differing from the spatial characteristics of the subjected reactor. Then, undetermined blind source separation was adopted to remove the acoustic components which are different from the frequency domain characteristics of the subjected reactor. Laboratory and substation tests were conducted, respectively. The results show that the method proposed in this research can obtain the acoustic signal with a power spectrum similarity of 0.924 from the original mixed acoustic signal with the power spectrum similarity of 0.617, which can verify the feasibility of the method.

Experimental Validation of a Mitigation Method of Ferranti Effect in Transmission Line

Electric power transmission networks should be operated in efficient, safe, and reliable conditions. To improve the stability and transfer capability of power transmission, it is necessary to mitigate the Ferranti effect. This paper investigates the impact of increasing the length of the transmission line on its receiving end voltage under no-load conditions. A variable shunt reactor compensation for transmission lines is used to control the voltage level at different lengths of the transmission line. The proposed method demonstrates that the value of the shunt reactor required to maintain the receiving end voltage can be estimated. Moreover, the system is modeled using the PowerWorld simulator, and the effectiveness of the proposed model has been verified by experimental results. The experimental results demonstrate the efficiency of the proposed methodology and match the simulation results, which are then validated by simulating the WSCC 9-bus and IEEE 30-bus test systems.

ДВУСПИРАЛЬНЫЙ МАГНИТОКУМУЛЯТИВНЫЙ ИСТОЧНИК СВЕРХСИЛЬНЫХ МАГНИТНЫХ ПОЛЕЙ

The relevance At present, the issues of creating an original design of a highly efficient explosive magnetic (magnetocumulative) generator, developing its mathematical model and conducting experimental research in this direction are topical in science and technology. Aim of research Consider the possibility of building new aircraft fuel ignition devices based on a double-helix magnetic-cumulative generator, solving the problem of confirming its advantages over known and proven methods by creating a mathematical model. Research methods Literature review and patent study, obtaining a mathematical model with experimental studies on full-scale samples in real operating conditions. In the course of the work, methods of the theory of electrical circuits, magnetic field, elements of mathematical analysis and the theory of electrical oscillatory processes (beats, resonance, etc.) in complex circuits were used. Results As a result, a relation was obtained that determines the maximum value of the beat frequency between two electrical circuits connected by a weak capacitive coupling, which makes it possible to carry out the calculations necessary when creating a magnetocumulative generator with high microwave radiation and during its regulation. Thus, the mathematical model of a magnetocumulative generator presented in the article is based on a fundamentally new combination of the application of the laws of electrodynamics and the theory of electrical oscillatory processes. On the basis of this model, proposals have been developed for using the proposed design with the original circuit design. The results of the work can be used in the ignition system of aircraft at an altitude of more than 20 km, which is a world problem, as well as to improve the efficiency of a shunt reactor, an installation for de-icing, mechanical engineering, medicine, military equipment, radio physics, etc.

Determining optimal neutral reactor to limit overvoltages and duration of secondary arc of transmission lines

AbstractEven though shunt compensation of transmission lines (TLs) is a common practice to limit the overvoltages stemming from the Ferranti effect, it may cause transient and steady‐state resonant overvoltages when one phase is left open due to the single‐pole‐open condition following the temporary phase‐to‐ground (Ph‐g) fault. Furthermore, the existing shunt reactors potentially increase the duration of the secondary arc current at the fault point and hence prevent offering fast single‐pole reclosing. To exploit the mentioned issues, in recent studies, a neutral reactor is introduced, which is installed in the neutral point of the shunt reactors; nonetheless, obtaining the appropriate amount of it is remarkably challenging. In this paper, an optimal neutral reactor (ONR) is determined based on an optimization problem, which minimizes the neutral reactor cost subject to limiting both resonant overvoltages and the duration of the secondary arc current. In modelling, the Laplace domain is employed rather than the phasor domain to consider both transient and steady‐state conditions since this technique allows having better control over transient overvoltages as well as transient secondary arc.

Multi-area distribution grids optimization using D-FACTS devices by M-PSO algorithm

This paper presents a model for the optimization of a multi-area distribution grid considering the high penetration levels of photovoltaic (PV) resources and electric vehicle charging station (EVCSs) based on distributed flexible AC transmission system (D-FACTS) devices including on-load tap changer (OLTC) transformers and step voltage regulator (SVR) tap control and shunt capacitor (SC) and shunt reactor (ShR) to reduce losses and voltage deviation. The overarching research aim was to avoid the overvoltage caused by power injection by PV sources and the voltage drop caused by charging EVs in distribution grids. The proposed model was designed based on distribution network load flow and was optimized using a modified particle swarm optimization (M-PSO) algorithm. Two different test networks were tested under different scenarios to analyze the proposed model, revealing the efficiency of the proposed model.