Shunt Reactor Research Articles

Influence of Transient Overvoltage in a High-Voltage System During Shunt Reactor De-Energization

Influence of Transient Overvoltage in a High-Voltage System During Shunt Reactor De-Energization

Controlled single-phase auto-reclosing technique for shunt reactor compensated lines in electrical energy systems transmission lines

A new controlled Single-Phase Auto Reclosing (SPAR) technique for Shunt Reactor Compensated Transmission Line (SRCTL) in electrical energy systems is presented in this paper. The suggested technique uses a Circuit Breaker (CB) with a Controlled Switching Device (CSD) and a Pre-Insertion Resistor (PIR). This said type of combination is available without any additional investment in the substation designed at 220 kV and above. The proposed technique performs Fourier Transform (FT) analysis of the acquired discrete samples of line side voltage of faulty phase during the Dead/Deionised Time of CB (DTCB). Furthermore, an assessment of the suggested scheme is done by generating a model similar to the present 400 kV, SRCTL in the PSCAD software environment. Moreover, the suggested scheme has been evaluated considering wide variation in parameters such as line length, compensation level, period of fault, fault inception angle, position of fault, effect of Switching Arrestor (SA) and the effect of different grid sources. At last, a comparison between the suggested scheme and the reported technique indicates the effectiveness of the suggested scheme when the Operating Time Scatter (OTS) (± 1 ms) of CB is taken into account.

Investigation on Power Frequency Following Current for Vacuum Circuit Breaker Interrupting Shunt Reactor in Offshore Wind Farms

Investigation on Power Frequency Following Current for Vacuum Circuit Breaker Interrupting Shunt Reactor in Offshore Wind Farms

Effect of shunt reactor rating on the switching transients overvoltage in high voltage system

Effect of shunt reactor rating on the switching transients overvoltage in high voltage system

Defect recognition of oil‐pressboard insulation based on frequent arc reignition phenomenon under switching impulse voltage

AbstractIn the past three years, a number of oil‐immersed ultra‐high‐voltage shunt reactors have experienced discharge defects when being put into operation, resulting in an overload of acetylene. However, detecting and identifying these discharge defects caused by switching impulse voltage is challenging under steady‐state conditions. This poses unpredictable and difficult‐to‐assess safety risks for the longterm operation of the equipment and subsequent transient processes. Hence, comprehending the discharge behavior of oil‐pressboard (PB) insulation under switching impulse voltage and devising a method to identify defects becomes crucial. This study focuses on investigating the frequent arc reignition (FAR) pattern exhibited by typical defects under both standard and oscillation switching impulse voltages. The objective is to uncover the mechanism behind FAR and propose a defect recognition strategy suitable for transient processes. The study reveals the FAR process will occur at least once during the breakdown process; the FAR phenomenon is the weakest in the surface defect with a weak vertical electric field. The average recovery voltage percentage and the average discharge interval of the FAR process decrease with increasing impulse amplitude or oscillation frequency. Additionally, the average number of discharges decreases with higher oscillation frequency, while it initially increases and then decreases with increaseing amplitude. Based on the analysis of the number of FAR processes and their variation in terms of amplitude or discharge interval, a method for recognizing oil‐PB defects during switching transient processes is developed and successfully applied to a case study involving acetylene overload in a 1000 kV shunt reactor.

Placement of controlled shunt reactors in 330 kV electrical networks and study of their operating modes

The improvement of the method for selecting shunt reactors based on instantaneous power in order to eliminate a surplus of reactive power created by the charging capacities of power transmission lines in 330-500 kV elelctrical networks of the power system is considered. Based on the proposed method, the performance of controlled shunt reactors located in priority 330 kV nodes of a real power system is superficially described and their operating modes are studied. As a result of the study, in accordance with changes in the modes of shunt reactors in real time, the voltage in the 330 kV buses is maintained in a stable and acceptable range, as well as the increase in the voltage stability of the power system.

Optimal Shunt Reactor Planning for Offshore Wind Farm

Optimal Shunt Reactor Planning for Offshore Wind Farm

Gas Production Characteristics of Partial Discharge in Needle-plate Electrodes under Typical Vibration Conditions in a UHV Shunt Reactor

Gas Production Characteristics of Partial Discharge in Needle-plate Electrodes under Typical Vibration Conditions in a UHV Shunt Reactor

Study on the Capacitive Effects of Underground Power Cables on the Operational Electricity Distribution Network

In this study, known compensation methods are mentioned and the reactive components of medium voltage underground cables used in the lines are emphasized. Iğdır University electricity distribution network is considered as the application area. Based on the information that XLPE type medium voltage cables used in electricity distribution networks show capacitor properties when they are unloaded, capacitive analyses of medium voltage cables forming Iğdır University electricity distribution network were made by considering the distance and cross-sections of the medium voltage cables, the layout plan and single line diagram of the distribution network were drawn and the powers of the transformers were classified. Iğdır University electricity consumption components were analyzed and what should be done was investigated. Because as a result of the researches, it was learnt whether the capacitive consumption is caused by the cables or the wrong connection of the meters or the presence of loads with permanent capacitive properties in the system. A shunt reactor panel was designed for capacitive consumption caused by the presence of XLPE (Cross-related Polyethylene) cables and the results were analyzed. A comparative evaluation of the results of the economic analysis of this shunt reactor panel was carried out. A pricing system has been established in which these limits will not be exceeded.

Analysis and mitigation techniques of overvoltages due to insulator transient arcs clearing on a 500 kV OHTL

In high-voltage OHTL, Overvoltages and arc currents due to insulator transient arcs clearing severely affect the stability of power systems.In this paper, a 500 kV Egyptian OHTL was simulated using ATP-EMTP software package. The insulators transient arcs clearing of the system were tested under different impedances of tower footing, locations of insulator arc tower, angles at which the arc initiate. Additionally, the effects of the corona phenomenon were taken into account to achieve realistic study. Furthermore, these factors thoroughly were analyzed to determine worst-case scenarios. Also the paper evaluated the performance of the overvoltage mitigation methods based on the installation of neutral shunt reactors, MOSA (Metal Oxide Surge Arresters), or combinations of both.The results demonstrated that the combination of MOSA and neutral shunt reactors was the most effective mitigation technique, reducing overvoltages by approximately 57.4 %, arc currents by 80 %, and arc extinction time by 27.3 %Notably, the most severe overvoltages and peak arc currents occurred at an angle of θ = 180° and footing impedance 30Ω. Additionally, the corona phenomenon played a role in reducing the severity of overvoltages, arc currents, and arc extinction time by approximately 56 %, 56 %, and 1.8 %, respectively. Finally, These findings provide valuable recommendations for mitigating overvoltages, arc currents, and arc extinction time during insulator arc clearing events.

A novel method of overvoltage suppression due to de-energization of shunt reactor in high voltage system

<span lang="EN-US">Substations usually employ shunt reactors to reduce the reactive power of systems. Due to current chopping when the shunt reactor is shut off, a high frequency and amplitude overvoltage is generated. This study was aimed at eliminating switching-related overvoltages in shunt reactors so as to maintain the equipment, prevent insulation failure, and avoid reignition. Therefore, the circuit was modified according to the suggested mitigation strategy to verify that transient overvoltages are suppressed by the circuit breaker and shunt reactor. With a view to evaluate the existing chopping caused by the switching of reactor bank, the alternative transients program (ATP-Draw) model was used to simulate the transients resulting from switching a shunt reactor. This work has been put into practice for various current chopping values. The collected results of the simulation showed that the proposed model was significantly highlighted for the suppression of overvoltages, with the voltage across the circuit breaker being reduced from 679 KV to 478 KV at a current chopping value of 5 A and from 351 KV to 152 KV across the shunt reactor.</span>

Modeling of power reactors for VFTO simulations: Full-scale design in a real application

The shunt reactors operate under a very specific conditions in Gas Insulated Substations - GIS, especially during very fast electromagnetic transients due to switching and maneuver operations. A meticulous electromagnetic analysis for correct design of such power devices, especially on the insulation coordination between turns, discs, and from winding to ground. This article presents a step-by-step modeling methodology based on the Finite Element Method, which is applied during the conception and manufacturing of a real shunt reactor for GISs. Finally, the time- and frequency-domain simulations are compared with experimental data obtained from laboratory tests.

Optimizing the Design of a Dry-Type Single Phase Gapped-Core Shunt Reactor to Empower National Industries

The import dependency of essential components in our country's electrical power system poses a significant challenge, emphasizing the importance of focusing on the design, development, and maintenance of power system components, particularly shunt reactors, from an economic standpoint. Domestic production of these components contributes to employment opportunities and enhances self-sufficiency. This study aims to address these challenges by optimizing the design of a dry-type single phase gapped-core shunt reactor with a rating of 100 kVAr and 10 kV. The reactor operates at a frequency of 50 Hz and experiences a maximum core flux density of 1.2 T. The study thoroughly examines the fundamental aspects related to the design of gapped-core shunt reactors. An optimal design is achieved by determining the optimal ratio of the cross-sectional area to the height of each core disk, employing a MATLAB code to minimize the reactor's initial manufacturing cost (IC) or losses. In addition, the proposed design undergoes simulation and analysis using the finite element method (FEM) in the MAXWELL software. The reactor's inductance is obtained through both Maxwell three-dimensional (3D) simulation and analytical methods, demonstrating a reasonable agreement that validates the effectiveness and reliability of the proposed approach.

High voltage shunt reactor acoustic signal denoising based on the combination of VMD parameters optimized by coati optimization algorithm and wavelet threshold

The goal of this research is the application of variational mode decomposition (VMD) in the denoising process of acoustic signals from high-voltage shunt reactors. This paper propose a unique joint denoising method that combines improved VMD and wavelet threshold. The coati optimization algorithm (COA) was introduced to optimally find the optimal combination of VMD decomposition parameters. The optimized and improved VMD was then used to decompose the original noisy reactor acoustic signal. The correlation coefficient method was introduced to remove uncorrelated intrinsic mode functions (IMFs). The wavelet threshold denoising algorithm was applied for secondary noise reduction on the extracted IMFs. The denoised IMFs were subsequently superimposed and reconstructed to obtain the denoised acoustic signal. Comprehensive comparison and analysis of these methods were conducted through simulation experiments and practical tests. The results indicate that COA-VMD-Wavelet Threshold—significantly reduces the reconstructed signal errors with high practicality and effectiveness.

Development and Application of User-Defined Variable Shunt Reactor (VSR) Model for Power System Analysis

Development and Application of User-Defined Variable Shunt Reactor (VSR) Model for Power System Analysis

Thermal Simulation and Analysis of Dry-Type Air-Core Reactors Based on Multi-Physics Coupling

A reactor is an important piece of equipment used for reactive power compensation in power system and has a significant impact on the safe operation of power system. Thermal behavior is one of the main causes of reactor failures. For an accurate analysis of the thermal behavior of reactors, electromagnetic–thermal–fluid multi-physics coupling modeling is chosen. However, there is a huge difference in size between the overall structure of the reactor and its insulating material, which makes it difficult to perform mesh generation, resulting in dense mesh and significantly increased solution degrees of freedom, thus making the solution of the reactor’s multi-physics field model very time-consuming. To address this, this paper proposes a simplified processing method to accelerate the solution calculation of the reactor’s multi-physics model. This method calculates the equivalent turns of each encapsulate with parallel coils in the reactor, simplifying the encapsulate into a single-layer coil, thereby greatly reducing the division and solution degrees of freedom of the multi-physics model, and thus accelerating the simulation calculation. Taking a BKDCKL-20000/35 dry-type air-core shunt reactor as an example, the outer diameter of the coil is nearly 12,000 times bigger than the coil insulation, which is a huge size difference. Both refined models and simplified models are established. Compared to the simulation results of the detailed model, the simplified model demonstrates good accuracy; the maximum relative error of temperature is just 2.19%. Meanwhile, the computational time of the simplified model is reduced by 35.7%, which shows promising effectiveness and significant potential for applying the optimization design and operation prediction of dry-type air-core shunt reactors for enhanced thermal performance.

Research on 750kV Reactor Vibration Based on Electromagnetic-mechanical Field Coupling Finite Element Model

The vibration signal characteristics of a 750kV shunt reactor with high voltage level and high vibration amplitude is one of the important indexes to evaluate the operating condition of the reactor. Since the high level of safe operation with Ultra-high voltage power equipment, it is challenging to collect long-term and extensive vibration signal data under safe operating conditions. This paper establishes the electromagnetic-mechanical field coupling finite element model (FEM) of a 750kV shunt reactor under a COMSOL open-source simulation environment. The resonance effect of magnetostriction of the iron core and the Maxwell forces between the iron core discs on the reactor structure is analyzed. The vibration distribution and typical frequency characteristics of each part of the 750kV shunt reactor are analyzed to provide a reference for the research of vibration fault diagnosis of Ultra-high shunt reactor.

Modeling and simulation of extra high voltage magnetically controlled shunt reactor based on PSCAD

For the two typical topologies of the extra high voltage magnetically controlled shunt reactor (MCSR), this study introduces its specific wiring methods and working principles. It conducts an analysis of the change characteristics and response characteristics of the core magnetic flux under different wiring modes of the controlled shunt reactor body. Based on PSCAD, two typical structures are used to model the body of the first 500 kV MCSR put into operation in a provincial power grid and perform steady-state and dynamic simulations. The results of field experiments are compared and analyzed. The winding connection mode of the device’s body electromagnetic transient model is determined, which lays a foundation for the follow-up research.

ANALYSIS OF RWANDA’S GRID POINT OF STABILITY LOSS

E Electricity stability is the key component in ensuring reliable power supply which is a major hurdle in most developing countries. Power angle being part of grid stability pillars, this work sought to theoretically and numerically investigate the maximum power angle variation that the power system in Rwanda could experience while maintaining transient stability at an acceptable range beyond which generators lose synchronism affecting overall system stability. A steady state and dynamic stability assessment of the lightly loaded Rwandan grid is conducted using PSS/E while MATLAB is used to obtain input values for calculating the system stability power angle. This involved collecting actual network parameters, creating an accurate model of the entire Rwandan grid and validating the model simulation results using regularly metered values at various critical busbars of the network. Results from the study show that a sudden drop in load of 11 MW and 6 MVAr leads to a variation of power angle of the largest power plant by 23o triggering transient stability problems leading to loss of synchronism. Both calculated and simulation results show that, a sudden power angle variation of between 23o to 23.5o at the swing bus power plant, causes the monitored generating units to trip triggering a long-term instability. This was done while also interrogating possible mitigation measures based on the developed and validated model. Based on the system status, the study revealed that the grid point of stability can be determined through simulation using software and to further obtain optimum stability, installation of active devices such as shunt reactors helps the grid to counter sudden variation of power angle due to line and load tripping. B

33kV cable connector failures due to shunt reactor switching by means of vacuum circuit breaker – A thorough investigation & mitigation analysis

Switching of (small) inductive currents by means of vacuum circuit breakers may lead to multiple re-ignitions. This is the result of the ability of the interrupter's quenching capability, which generates steep overvoltages that can stress the equipment insulation. Should no mitigation measures be applied, the equipment is exposed to a high risk of failure. In this paper, the findings and conclusions of a such a failure investigation and mitigation analysis are presented, referring to multiple cable connector failures in 33kV shunt reactor installations in the Netherlands.