High-speed Circuit Breaker Research Articles

Mitigation of overvoltage in LVDC distribution system with constant power load using generic energy storage system

The operation of a high-speed DC circuit breaker can cause overvoltage transients in the Low Voltage Direct Current (LVDC) distribution system, especially when driving a constant power load (CPL). Without adequate damping, the destabilizing effect of the CPL can push the system towards instability. This paper proposes a novel approach to mitigate over-voltage transients caused by DC circuit breaker operation in the LVDC system using a generic energy storage system (GESS). The paper begins by introducing the concept, modeling, coordinated operation and practical application of GESS. GESS employs both power-centric storage, such as supercapacitors, to limit the switching over-voltage within safe limits, and energy-centric storage, such as batteries, to ensure the energy sustainability. A state-space model of a detailed LVDC distribution system with CPL and GESS is subsequently developed. Additionally, to ensure system stability, analytical expressions are derived to determine the required sizing of the power-centric storage under different case scenarios. Simulation analysis using MATLAB's Control System Toolbox validates that GESS can stabilize voltage transients and reduce overshoots within 10 ms. Moreover, the proposed GESS solution is proven to be more reliable and cost-effective than supercapacitor and hybrid energy storage solutions. It is also scalable to larger LVDC networks and adaptable to different load scenarios.

Development and Application of PIKH-Type Current Sensors to Prevent Improper Opening of Parallelly Connected DC Vacuum Circuit Breakers

This article describes the development of current sensors used in DCU-type high-speed circuit breakers. DCU-type circuit breakers use the principle of turning off a constant short-circuit current by means of countercurrent. The article presents a new current sensor design called PIKh, which uses Hall sensors to measure current and determine its direction. PIKh sensors allow parallel operation of high-speed circuit breakers during the “parking” operation. The article includes the algorithm and principle of operation of the PIKh sensor. The proposed solution was verified on an electric traction vehicle.

Modern numerical relays in protection of power transformer

This paper presents various protection schemes and their respective modern numerical protection relays to protect the power transformer. Proper protection is needed for the economical and safe operation of electrical power systems. The power transformer protective relay should block the tripping during an external fault or magnetizing inrush and speedily operate the tripping during internal faults. The objective of this paper is to implement protection during in-zone and outzone faults and to operate the relay with proper selective discrimination. The basic approach is to disconnect the power transformer feeder against in-zone faults and prevent disconnection of the power transformer feeder due to other operating conditions. The protection relay was able to discriminate between 2nd harmonic inrush, in-zone fault, and out-zone fault conditions. The protection scheme consists of high-speed protection relays and circuit breakers, which are required for the protection of substation equipment against abnormal conditions. A protective relay senses the fault and determines the location of the fault. Then, the protective relay sends the tripping command to the circuit breaker. Therefore, proper care should be taken in designing and selecting an appropriate relay that is reliable, efficient, and fast in operation. The PT and CT continuously measure the voltage and current of the substation and are connected to the relays to enable them to detect abnormal conditions. This paper describes numerical protection for power transformers, especially when the rating of the system is 50 MVA, 110/33 Kv, and Dyn11 at the substation. The protection relay employed in the transformer feeder is 7SR24 type (Siemens make).

Zero-sequence current suppression control for fault current damper based on model predictive control

In a multi-terminal direct current (MTdc) system based on a modular multilevel converter (MMC), high-speed and large interruption capability direct current circuit breakers (dc CBs) are required for dc fault interruption. However, commercializing these breakers is challenging, especially offshore, due to the large footprint of the surge arrester. Hence, a supplementary control is required to limit the rate of current rise along with the fault current limiter. Furthermore, the operation of the dc CB is not frequent. Thus, it can lead to delays in fault interruption. This study proposes the indirect model predictive control (MPC)-based zero-sequence current control. This control provides dc fault current suppression by continuously controlling the zero-sequence current component using circulating current suppression control (CCSC) and by providing feedback to the outer voltage loop and inner current loop of MMCs. The proposed control is simulated for pole-to-pole and pole-to-ground faults at the critical fault location of an MTdc system. The simulation is performed in Real Time Digital Simulator (RTDS) environment, which shows that the predictive control reduces the rate of rise of the fault current, providing an additional 3 ms after the dc fault occurrence to the dc CB to clear the fault. Besides, the energy absorbed by the dc CB’s surge arrester during the pole-to-pole and pole-to-ground fault remains the same with the proposed control.

Design and Study of the Key Characteristics of a New DC Vacuum Interrupter With a High Peak and Low Residual Magnetic Field

With the rapid development of multiterminal high-voltage direct current (HVdc) transmission systems, the research and development of high-speed and stable high-voltage dc circuit breakers have received attention. Among them, mechanical dc circuit breakers based on manual zero-crossing dc breaking technology have been applied in practical projects, owing to their small size, low on-state loss, and low price. However, this method adds a high-frequency current, which deteriorates the magnetic field between the poles of the interrupter when the arc is broken. Therefore, the development of HVdc circuit breakers that maintain high peak magnetic fields and low residual magnetic fields at high frequencies has become the key to the development of multiterminal HVdc transmission. To solve this problem, this article proposes a new interrupter for a vacuum dc circuit breaker based on artificial zero-crossing technology and studies its key characteristics, such as temperature rise, electromagnetic field, and arc column plasma distribution characteristics. The results reveal that the new interrupter proposed in this article has a low-temperature rise, uniformly distributed electric field, high peak value and low remanence of the longitudinal magnetic field, and uniformly distributed plasma in the arc column, and exhibits arc diffusion. Its ability to cope with high-frequency current is significantly higher than that of the traditional cup-shaped axial magnetic field (AMF) contact system interrupter, which is conducive to the high-speed and stable breaking of the interrupter.

HVDC grid fault location method using genetic algorithm on reconstructed frequency-domain voltage profiles

This paper presents a novel frequency domain based fault location method for High Voltage Direct Current (HVDC) grids. The method relies only on short data windows (below two milliseconds) of single-ended voltage measurements, thus rendering the technique practically applicable to HVDC grids employing high-speed circuit breakers. Based on the available post-fault voltage traces, a frequency domain profile of voltage transfer function is initially constructed, which is then iteratively evaluated against theoretical voltage profiles, synthesized with the use of travelling wave principles. The evaluation routine is based on a genetic algorithm (GA) regime, which once terminated indicates a close approximation to the feeder’s fault location. The result of this process is further refined using a weighted averaging function to obtain the final fault distance estimation. The performance of the proposed method is demonstrated using comprehensive electromagnetic transient (EMT) simulation studies conducted on a four-terminal meshed HVDC grid using PSCAD/EMTDC. The results revealed that the method can estimate the fault location with high accuracy for all transmission media types, including hybrid lines that comprise of cable and overhead line segments. Moreover, it has been found that the method maintains its accuracy for very long transmission lines, highly-resistive faults and different fault types.

Analysis of 3 kV DC Contact Line High-Speed Circuit Breaker Unit Protection Scheme Limitations

The High-Speed Circuit Breaker (HSCB) is a de-facto electro-mechanical contact line protection device employed in the 3 kV DC traction power supply system. The breakers installed at the terminal ends of the contact line make a unit protection scheme configuration. While the HSCBs seem to trip under fault conditions, there is an unknown source that keeps on supplying residual current into the faults. This necessitates some explanation of the source of energy of the continual flow of residual energy. This paper makes an analysis of the limitations in the HSCB unit protection scheme using MATLAB simulation and how the scheme can be optimized with digital protection devices augmented with a peer-to-peer transfer trip as an end-to-end protection solution.

A differential operation principle of the automatic bus transfer system pickup unit as a way of decreasing the emergency clearing time.a

A proper choice of the design and operation algorithm of emergency control devices like high-speed bus transfer (HSBT) is only possible proceeding from a study and analysis of steady-state and transient processes in emergency modes of operation (short-circuit faults, power supply disconnection, or phase open-circuit fault). The numerical experiments for studying such modes that were carried out, using the Matlab Simulink software package, on the mathematical models of an industrial power supply system involving synchronous motors connected to it made it possible to synthesize a new differential HSBT pickup unit featuring a high-speed response to emergency events. In doing so, special attention was paid to an analysis of transient operation modes with the aim of minimizing the probability of false actuations. The obtained study results have found practical application in the HSBT devices installed at the facilities of PJSC MOSENERGO. The experience gained from the operation of a new device jointly with high-speed circuit breakers produced by the Tavrida-Elektrik state-owned corporation has demonstrated essential advantages in comparison with the conventional HSBT designs.

PSCAD/EMTDC를 활용한 초전도 소자의 유무에 따른 기계식 DC 차단기 분석

With the announcement of a policy to reduce carbon emissions, the range and technologies of renewable energy sources are increasing. In new renewable energy, the amount and range of solar power generation is relatively gradually expanding[1]. Based on the high-speed DC circuit breaker used in the solar power generation, we combined the LC divergence oscillation circuit and the superconducting element that this research team is working on. This is to protect peripheral equipment against an increase in solar power generation and unspecified disturbances. The DC circuit breaker, we propose is a mechanical DC circuit breaker with a superconducting element applied. The superconducting element can lower the initial fault current within about 2 ㎳ through the quenching operation. However, it takes a large power burden and a long time to cut-off the fault current. In the mechanical DC cut-off part, the existing high-speed mechanical circuit breaker, LC divergent oscillation circuit and Surge Arrestor are connected in parallel to safely and reliably cut off fault current. The characteristics of the cut-off operation that appear when a superconducting element and an LC divergent oscillation circuit are combined with a conventional mechanical DC circuit breaker were analyzed. As a result, through the application of the superconducting element, the speed at which the artificial zero-point of the fault current occurs was reduced, and the time to complete the shutdown was shortened.

Parameter estimation of DC black-Box arc models using genetic algorithms

This paper presents a method for estimating the black-box arc parameters using genetic algorithm. The proposed method is applied to represent a DC short-circuit in a railway system protected by a High-Speed Circuit Breaker (HSCB). The simulated cases were compared with experimental data, and the results show very good agreement between model predictions and experiments. This method could potentially be used by HSCB’s manufacturers to extract and provide arc model parameters to end users based on their test results.

Modernization of a System of Protecting Adjacent DC Traction Network Feeders

The partitioning of railroads electrified on dc is done with the help of insulating air gaps (IAGs). When the pantograph collector of an electric locomotive crosses the branches of an IAG, an increment in current occurs in the feeder of the traction network entered by the electric locomotive. In these cases, the nonselective operation of a high-speed circuit breaker (HSCB) results in its false response, disconnection of the traction network power supply area, and, ultimately, stops the train. To preserve the reaction of the protection to a remote short-circuit and avoid false tripping in circuit-breakers, an interlocking circuit is proposed that prevents the tripping of HSCBs of adjacent dc traction network feeders at an instantaneous increment in current.

An experimental analysis of DC magnetic blowout high-speed circuit breakers’ parameters

High-speed circuit breakers (HSCB) used in DC circuits are one of the basic elements of overload, short-circuit and electric shock protection. Such breakers are used in transport (trams, trolleybuses, subways and railways) in electric power supply facilities and in vehicles. The performance and capability of limiting the current depend on the HSCB design and solutions applied in it. The circuit parameters, particularly its inductance also affect the performance. Additionally, each DC breaking in the RL circuit is accompanied by overvoltages whose level depends on the circuit parameters and breaker design. The paper discussed the process of direct current breaking by magnetic blowout high-speed circuit breakers and factors that affect the HSCB performance, i. e. opening time and arcing time. The influence of the circuit parameters and HSCB design on the value of arc voltage is outlined. The results of laboratory tests of 4 types of high-speed circuit breakers produced in Europe are presented. The test results were used to analyze the effect of current changes in the short circuit on the time of current breaking and the value of switching overvoltages – arc voltage. The results of simulation of the short-circuit breaking in the RL DC circuit made at the rate-of-rise of current in the circuit are presented. Based on the tests and simulations, the current breaking times, values of arc voltage generated in this process and arc energy that is acquired and dissipated by the arc chamber are determined. The objective of the tests and simulations was to answer the question whether it is possible to turn off direct current quickly without generating high arc voltage values – overvoltages in the circuit and how di/dt changes should be formed by a high-speed circuit breaker to achieve the shortest possible time with the lowest possible arc voltage and its lowest energy

Phasor-based fault location challenges and solutions for transmission lines equipped with high-speed time-domain protective relays

This paper presents a study on the performance of phasor-based fault location methods under reduced fault period conditions. Such a scenario can arise in lines equipped with high-speed circuit breakers (CBs) and time-domain protective relays, so that the fault can be eliminated even before it reaches its steady-state. Considering this context, challenging scenarios that may arise during phasor-based fault location procedures are firstly addressed, and then statistical approaches for fault location estimation sample processing are investigated, evaluating their advantages and limitations. Initially, Alternative Transients Program (ATP) fault simulations are carried out to generate realistic fault records, which are played back into actual micro-processed relays equipped with both high-speed time-domain protection functions and phasor-based fault location algorithms. Finally, by means of tests using a Real-Time Digital Simulator (RTDSTM) and an actual Digital Fault Recorder (DFR), different procedures to analyze phasor-based fault location data are assessed. The obtained results show the statistical processing of fault location estimations can improve existing fault location procedures in some cases, but not completely solving the problem if CBs come to be faster than those in the present technology.

Research on Safety Technology for High-Speed Interruption for Mining Flameproof Movable Substation

Due to the working condition of low-voltage cabling from the mining flameproof movable substation to the loads of the mining face being poor, it is easy to cause various external mechanical damages to the cable sheaths. Furthermore, a single-phase earth leakage fault or short-circuit fault can occur when the low-voltage cable sheaths are damaged, and electric sparks caused by these faults can lead to a gas explosion. As the gas detonation time caused by the above faults is usually more than 5 ms, the high-speed interruption solid-state switch which controls the cables must cut off the current within 3 ms. This requires the action time of the solid-state switch to be less than 1 ms, and at the same time, the sampling and calculation time of the relay protection must be less than 2 ms. Based on these problems, this paper proposes the use of a high-speed solid-state circuit breaker (SSCB) topology at the neutral point of transformer, and analyzes the conduction mechanism and shut-off mechanism of the current of the SSCB. It presents an ultra-high-speed algorithm based on pattern recognition of single-phase earth leakage fault protection, and an ultra-high-speed algorithm of short-circuit fault which is based on the rate-of-change of the current. Finally, through computer simulation experiments and semi-physical simulation experiments, the feasibility of the above three technologies is verified to ensure that when a single-phase earth leakage fault or short-circuit fault occurs in the low-voltage cable, the solid-state switch which is installed in the mining flameproof movable substation will cut off the current within 3 ms.

Блокировка несанкционированного срабатывания быстродействующих выключателей в тяговой сети постоянного тока

Electric railway is a system of very complex interconnected technical structures. High-quality operation of the power supply system depends on successful solution of a number of technical tasks by applying an integrated approach and introducing various scientific-technical measures. The traction network state is becoming of special importance. When an electric locomotive’s pantograph moves along the branches of the insulating air gap and when a transition is made from one power supply zone to another, there is a high probability of false disconnection of power supply to the branch the electric stock drives in. This may happen due to specific characteristics according to which the protection devices come in action. In this case, an electric arc emerges between the moving pantograph of the electric locomotive and the branch it leaves; this arc burns out the contact system wires. A device ensuring uninterrupted operation of DC traction network elements when an electric locomotive passes the insulating air gap is presented. The protective device in the form of a differential shunt relay, the use of which makes it possible to disconnect the traction network feeding line at a small value of a rapidly changing short-circuit current, serves as a prototype. The results from simulating a transient that occurs under such conditions in the traction network feeding lines are presented. Based on the obtained data, the parameters of a circuit for interlocking false disconnections performed by high-speed circuit breakers in the traction network adjacent feeding lines have been developed

Snr-enhanced continuous spatial filtering velocimetry on a high-speed circuit breaker using linear cmos

An optical spatial filtering velocimeter that measures the velocity of a high-voltage circuit breaker is proposed. We examined the velocimeter theoretically and obtained the requirements for spatial filters (SFs), such as the transmission function. Theoretical analyses and experiments show that the sinusoidal transmission function spatial filter (STSF) provides a higher signal-to-noise ratio (SNR) and better accuracy than the traditional rectangular transmission function spatial filter (RTSF). Experiments show that spatial filtering velocimetry (SFV) with an STSF can yield better measurement results than those produced with an RTSF.

Contact arc time – important parameter of DC high-speed circuit-breakers

The parameters of DC high-speed circuit-breakers (HSCB) and test methods are specified in the standards. These standards define requirements of the circuit breakers opening time and the total breaking time. During the direct current (DC) breaking after opening the contacts, the arc ignites, the voltage of which is so low that it does not limit the switched off current. The time in which this phenomenon occurs is defined as the contact arc time.The contact arc time has a significant influence on the breaking process. It can take up to over 40% of arcing time. Therefore, tests were carried out, which were to answer the questions about what and to a what extent affects the contact arc time.Since the standards for high-speed circuit-breakers do not refer to the contact arc time, definitions of this parameter are proposed in the article. Using this definition numerous tests of various factors have been carried out on contact arc time.The conducted research shows that shortening the DC breaking time through high-speed breakers is possible by limiting the contact arc time, which can be obtained by modifying the circuit breaker’s construction.

Parameters of DC high-speed circuit-breakers

DC high-speed circuit-breakers (HSCB) are the basic protection to cut off short-circuit and overload currents. People’s and railway infrastructure devices’ safety depend on their reliability and parameters. High-speed circuit-breakers, like any other electrical devices, display several electrical and mechanical characteristic parameters, which in many cases are interconnected. The article features these parameters of DC high-speed circuit-breakers that affect the operation safety of electric traction power supply systems. Moreover, it presents ways of their determination basing on laboratory and operational tests. Furthermore, requirements to be met directly and indirectly by DC high-speed circuit-breakers imposed by legal and standardization documents are described. Correlations between the breakers’ construction and their parameters are outlined. Basing on tests of leading European producers’ breakers, the article presents the impact of parameters of circuit where they are tested as regards HSCB parameters. It also deals with the problem of coordination of short-circuit protection and breaking currents of low values with respect to high-speed circuit-breakers used in Poland.

Пропускная способность ограничителей перенапряжений в составе вакуумных выключателей постоянного тока

The article presents the results from numerical simulation and experimental investigation of the throughput capacity of Type 0PN-TP-3.0/4-UKhL 3 metal-oxide surge arresters (MOSA) used as part of a high-speed automatic DC vacuum circuit breaker for the maximal voltage equal to 4.1 kV. The vacuum circuit breaker operation principle isbased on forced lymaking the disconnected current to pass through zero by means of arranging opposite discharge of a pre-charged capacitor. A numerical model is proposed, whichhas been implemented in the Matlab 6.5 software package using the Sim Power Systems library. The applicability of the model has been experimentally confirmed in disconnecting a current by a vacuum circuit breaker through simulating a short-circuit fault current with different current growth rates. The investig a tions were carrie doutata heavy-current high-voltage test bench realizing an oscillatory circuit involving a capacitor bank for the maximal voltage of up to 6 kV and the total energy storage capacity of up to 1.8 MJ. The numerical model satisfactorily describes the processes in disconnecting acurrentina DC vacuum circuit breaker with forcedly making the current to cross zero. The model also make sit possible to estimate the amount of energy dissipated in the MOSA unit in disconnecting a short-circuit fault current. Byusing the proposed model itis also possible to estimate the number of parallel-connected MOSAs in disconnecting emergency currents in traction DC power supply networks with an inductance ranging from 5 to 15 mH.

A Study on Protection Requirements for DC Faults in Multi-Terminal HVDC System

Recently, the construction of large-scale offshore wind farms and dissemination of new and renewable energy has encouraged a growing interest in DC systems. In particular, HVDC (high-voltage direct current) systems have been evaluated as the best alternative because of their power system interconnection and large-scale power transmission. Because HVDC systems offer many advantages such as a low insulation level, transmission losses, and improved power system stability, many studies on DC power systems are actively underway. As compared to the point-to-point HVDC system, which connects the electricity generated from geographically scattered renewable energy sources to an existing AC power system on a 1:1 basis, the MTDC (multi-terminal HVDC) system has garnered greater attention because of its ability to control energy flow by connecting several HVDC outputs to the HVDC. Because the VSC-HVDC, which operates as an MTDC, supplies not only active power, but also reactive power, it has been deemed the optimal solution to connect a renewable energy source to a system with no existing AC power supply, such as a wind-power generation system. An MTDC system, which possesses a structure that is more complex than that of the point-to-point HVDC system, should be equipped with a high-speed DC circuit breaker that can quickly separate a conversion station from the DC transmission line to which it is connected in the event of a fault or malfunction at the station. In addition, DC protection on the MTDC grid must be reliable and operate much faster than conventional AC protection to ensure that the converter sends a trip signal before it is damaged. In this paper, we propose a protection scheme for the DC line to effectively activate the DC circuit breaker, which is essential in an MTDC system; additionally, system modeling and simulation using the PSCAD/EMTDC were performed to verify the proposed algorithm.