Short-circuit Fault Currents Research Articles

Protection Coordination Strategy for the Distributed Electric Aircraft Propulsion Systems

The current trend in distributed electric aircraft propulsion systems is to utilize the DC bus system at higher voltage levels than conventional aircraft systems. With Boeing and Airbus utilizing the +/−270 V bipolar DC bus system, the research on high-voltage systems is increasing gradually, with voltage levels ranging from 1 to 10 kV systems or +/−0.5 to +/−5 kV DC bus systems. These voltage levels present considerable challenges to the distributed electric aircraft propulsion systems. In addition to partial discharge effects, there are other challenges, particularly the challenge associated with effectively limiting short-circuit fault currents due to the low cable impedance of the distribution system. The cable impedance is a significant factor that determines the fault current during fault conditions. Due to the low impedance, there is a sharp increase in fault current, necessitating an enhanced protection strategy, which ensures that the system is adequately protected. This paper introduces a coordinated protection strategy specifically designed for distributed electric aircraft propulsion systems to mitigate or prevent short-circuit faults. The proposed algorithm utilizes an I2t-based strategy and the current-limiting-based strategy to protect the system from short-circuit faults and overload conditions. Redundant backup protection is also included in the algorithm in case the circuit breaker fails to operate.

Strengthening distribution systems after earthquakes with a new analytical model

This study highlights that earthquakes can lead to short-circuit faults, power outages, and equipment damage in distribution systems. Based on the observation of the effects of two major earthquakes that occurred in Turkey (February 6, 2023), a new analytical model for strengthening distribution systems against natural disasters is proposed in this study. In this model, the distribution system is analyzed, and the fragility index of the buses is determined. The technical condition of the distribution system is assessed using fragility indexes, and integration and sizing of Distributed Generation (DG) and energy storage units are performed to ensure energy continuity after an earthquake. This fragility index takes into account both the operation of the distribution system in island (microgrid) mode and its operation connected to the main grid. In addition, with the fault index recommended within the scope of the analytical model, the vulnerable points of the distribution system against short circuit faults are analyzed and short circuit fault currents are limited at these points. Thus, the resilience of distribution systems against natural disasters such as earthquakes can be enhanced with the proposed analytical model.

Current Limiting Simulation of Magneto-biased Superconducting Fault Current Limiter (SFCL)Applied in 66 kV/10 kV Power Substation in China

The short-circuit fault currents in the large capacity transmission lines pose a challenge to the stability and safety of power system. Magneto-biased superconducting fault current limiter (MBSFCL) is with the advantages of two-stage current limiting, self-triggering and fast recovery so that it can effectively reduce the short-circuit fault current when applied to the urban power system. This paper analyzes the operation principle of MBSFCL and establishes a package type magneto-thermal coupled simulation model of MBSFCL based on MATLAB/SIMULINK. A power system model of a 66 kV/10 kV Zhang Tai Zi power substation which is in Liaoning province in China has been established and the grid-connected simulation applied MBSFCL has been achieved. Moreover, the grid-connected test is carried out, and the results of fault current, quench resistance and temperature change are obtained. The comparison of results between simulation and test verifies the accuracy of the simulation model and the application feasibility of MBSFCL.

Study on discharge characteristics of pulsed power module under the condition of discharge short circuit fault

Efficiency and safety are key factors that must be emphasized in pulsed power applications. The discharge characteristics of pulsed power supply directly determine the performance of the railgun. This paper conducts a research on short-circuit faults in transmission coaxial cables of pulsed power supply. In order to study the effect of short-circuit fault on the discharge characteristics of pulsed power supply and system efficiency,a pulse-forming network with cable short-circuit failure and dynamic railgun model are established in the paper. The effect of short-circuit fault on peak current is discussed by simulation. The results show that the short-circuit fault currents are all higher than the currents under normal conditions, and the closer the short-circuit location is to the power supply side, the higher the peak value of current is. In some extreme case, the peak fault current exceeds 1.5 times the normal, which requires consideration of short-circuit fault protection measures, such as the addition of a DC circuit breakers.

Analisis Sistem Pentanahan Gedung Pascasarjana Menggunakan Metoda Tiga Titik di Universitas Lancang Kuning

The grounding system is a way to channel the electric current that occurs due to a lightning strike on an object in the building there is an electrical system used for electrical and electronic equipment. The grounding system is used to secure buildings from fire hazards due to lightning strikes, secure electrical and electronic equipment and humans connected by wires or conducting cables to electrodes that are installed in the ground. The research method analyzes data from the data obtained to obtain large values of grounding resistance, short fault current, healthy phase increase and touch voltage and step voltage in the Unilak Postgraduate building. The purpose of this study is to analyze the value of the resistance of the grounding system, analyze the short-circuit fault current that occurs in the grounding system, analyze the phase voltage increase, and analyze the touch voltage and step voltage in the Lancang Kuning University Postgraduate building. By using the three-point research method, the calculation results on the grounding of the Postgraduate Building are 28 ohms, the neutral point resistance value is 0.00465 ohms, the touch voltage is 149.5 volts, the step voltage is 208 volts, the short circuit fault current calculation is 1, 15 amperes, while the healthy phase voltage increase is 308 volts.

Pengaruh Tahanan Jenis Tanah Terhadap Sistem Pentanahan Menggunakan Elektroda Batang Dilokasi Gedung Teknik Elektro Unimal

Providing a return line for short-circuit currents or fault currents to a low-resistance ground, grounding system is useful for achieving a uniform potential voltage over a given area of buildings and equipment. Because a large voltage difference can occur if a fault current is forced to ground against a high resistance. Placement of the electrode to be planted is one of the elements to obtain a low grounding resistance value. Grounding resistance measurements, which will serve as a guide for the grounding system design process, are required during the planning stage for certain types of grounding systems. The problem is how the grounding resistance is affected by the buried depth of the rod conductor and the soil type resistance. Therefore, it is very important to conduct research and testing to determine the extent to which these parameters influence. The experimental results of measuring resistance on dry and wet soils are on dry soil 30 cm obtained 98.48 Ω, 60 cm obtained 37.07 Ω, 90 cm obtained 20.52 Ω, 120 cm obtained 19.77 Ω, and for wet soil at a depth of 30 cm obtained 43.34 Ω, 60 cm obtained 22.21 Ω, 90 cm obtained 15.43 Ω, 120 cm obtained 11.66 Ω. So to get the 5Ω value we make an estimate by adding a depth of 56.603 cm for wet soil and 38.58 cm for dry soil, then the length of the electrode needed is 176.603 cm for wet soil and 158.58 cm for dry soil.

Implementation Of Generator Grounding Parameters Through Distribution Transformer Using Labview

Determination of the generator neutral grounding system through a distribution transformer can be done through manual calculations. Many parameters are considered in the calculation to obtain the appropriate result there is the possibility of repeated calculations. This is very difficult and causes a large difference in the calculation results. Therefore, a computer-based computing system is needed to overcome these problems. Several papers have developed the calculation of the required generator neutral grounding quantity which considers the voltage level, short circuit fault current, and protection system against ground faults. This paper makes modeling in designing a neutral ground generator using the LabView Graphical User Interface (GUI) application. The goal is to make it easier, faster, and more accurate. As the implementation of the modeling used data from std C62.92.2TM-2017.

Fast Y-Type Thyristor-Based DC SSCB Using Complementary Commutation in a Capacitor–Capacitor Pair Structure

This article proposes a new thyristor-based dc solid-state circuit breaker (SSCB) named Y-type. Main contributions focus on a new complementary commutation circuit including a capacitor–capacitor pair, which features three remarkable advantages. First, a fast commutation is achieved using a countercurrent pulse injection by the capacitor–capacitor pair structure. Second, metal-oxide varistors (MOVs) are disconnected from the power line when SSCB is <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> , which solves the reliability issue due to the MOV degradation and enhances the voltage utilization rate of the main switch. Third, benefiting from the capacitor–capacitor pair structure, reliable reclosing and rebreaking are obtained for practical applications. Experiments are conducted on a 400 V/120 A prototype to validate the proposed Y-SSCB. The peak voltage on the main and auxiliary thyristors reaches 773 and 400 V, respectively. Also, the peak voltage on the auxiliary capacitors pair reaches 740 and 400 V. The Y-SSCB achieves a fast reaction time of 80 μs in interrupting 120 A short-circuit fault current.

Design and Analysis of a DC Solid-State Circuit Breaker for Residential Energy Router Application

Energy routers act as an interface between the distribution network and electrical facilities, which meet the requirements of clean energy substitution and achieve the energy sharing and information transmission in the energy network. However, the protection of the dc load side of residential energy routers including interruption and isolation of short-circuit fault currents is vital for discussion. Since the traditional mechanical and hybrid circuit breakers for dc fault protection have the drawback of slow operation, a solid-state circuit breaker (SSCB) is an optimal solution for fast dc fault interruption. In this paper, a dc SSCB is proposed that uses an RCD + MOV snubber circuit, which is considered the best and most complete circuit used in common SSCBs. There are two main contributions in this paper: First, a dc SSCB is designed, which isolates both positive and negative terminals of a circuit and its working principle and operating modes along with the formulas for calculation of crucial time intervals, voltages, and currents along with the design procedure are provided. Second, a soft turn-on auxiliary is designed to prevent a high current surge caused by the capacitance difference between the source and the load. The experimental results demonstrate the proper performance of the topology and the validity of the findings.

Measurement of electromagnetic environment of hybrid DC circuit breaker during bipolar short circuit fault

Hybrid DC circuit breakers (DCBs) have recently been used to break short-circuit fault currents to ensure safety in flexible DC transmission projects. However, electromagnetic transients from DCB operation can interfere with the secondary equipment and cause malfunctions. In this paper, the bipolar short-circuit test, which is the first short-circuit test for DC transmission line in flexible DC project in the world, has been carried out in the 200 kV HVDC converter station equipped with two hybrid DCBs. The transient magnetic field near the secondary equipment in the DCB hall were measured, and its characteristics were discussed. Furthermore, the relationships among the space magnetic field, the short-circuit current and the action of the power electronic equipment in the DCB were also analyzed The main findings are as follows. During the bipolar short-circuit process, the maximum space magnetic field intensity near the secondary device is 109 A/m, and the maximum rising rate of the magnetic field waveform is about 350 A/m/ms. The magnetic field strength reached its peak value at the moment when the DCB was blocked, as well as the short-circuit current. It can be indicated that the DCB can cut off the short-circuit fault current accurately and reliably. The results can provide reference for the immunity evaluation and anti-interference protection of secondary equipment, and its optimal arrangement in the DCB hall.

Single AC/DC fault current limiter for both side of hybrid AC/DC microgrid

ABSTRACT Increasing short-circuit fault currents is one of the critical challenges in microgrids (MGs). In this paper, a novel AC/DC fault current limiter (ADFCL) is proposed to limit short circuit current of both DC and AC sides in hybrid AC/DC MGs (ADMGs). It includes two AC and DC ports, installed between AC MG (ACMG) and DC MG (DCMG). Also, it has only one common limiting resistor for limiting short circuit current in faulty MG without affecting the performance of the healthy MG. The proposed ADFCL power circuit, its principle of operation and control system are presented. Then, the feasibility of the ADFCL is verified by simulation in PSCAD/EMTDC environment and finally, a prototype is built. Both experimental and simulation results reveal that the ADFCL can limit the faulty MG by using only one limiting resistor without affecting the performance of the healthy one, which reduces the cost of using FCL in ADMGs.

Interrupting characteristics of a DC combined apparatus for rail transit systems

The short-circuit fault current of the urban rail transit systems is hard to interrupt due to the high amplitude and the high rising rate. The existing air DC circuit breakers applied in the rail transit DC traction system are difficult to interrupt the short-circuit fault current quickly and reliably, and cannot meet the increasing demand of the system capacity. The objective of this paper is to design a novel DC combined apparatus including a DC fuse module and an artificial zero crossing module series-connected to solve the problem of rapid isolation of short-circuit fault current in DC traction systems. The DC fuse module consists of a DC fuse and a transfer switch with additional auxiliary coils. Experimental results show that the DC combined apparatus can interrupt the rated current, overload current, and short-circuit current effectively within 6 ms. It can interrupt a 20 kA overload current within 5.12 ms, and the interrupting time of a prospective short-circuit current of 100 kA is less than 5.08 ms. The designed DC combined apparatus has the full range of current interrupting capacity and has the advantages of low on-state loss and low cost, which can significantly improve the reliability and stability of rail transit systems.

Analysis of Combined Resistive Superconducting Current Limiter

Based on a brief analysis of the discovered quench mechanism and basic model of the resistive superconducting current limiter, in order to alleviate the defects of the conventional resistive superconducting current limiter, a Combination of fault current limiting operating modes of the current transformer. A custom model of resistive superconducting current limiter was built on the PSCAD/EMTDC simulation platform, and based on a 200kV DC transmission system, the influence of the combined operating mode resistive superconducting current limiter on the circuit was studied, and it was shown that the Define the correctness and necessity of the model. The simulation results show that the resistive superconducting current limiter in the combined operation mode can effectively suppress the short-circuit fault current, reduce the system’s requirements for the breaking capacity of the DC circuit breaker, and improve the safety of the system operation.

Short-Circuit Fault Current Modeling of a DC Light Rail System with a Wayside Energy Storage Device

This paper proposes a simulation model to calculate short-circuit fault currents in a DC light rail system with a wayside energy storage device. The simulation model was built in MATLAB/Simulink using the electrical information required to define a comprehensive DC traction power rail system. The short-circuit fault current results obtained from the simulation model were compared with hand calculation results obtained using EN 50123-1 guidance. The relative error was 1.02%, which validates the model. A case study was carried out for a 1500 V DC light rail system. In the case study, a method was proposed to assess the DC protection and the withstand and breaking capacity of the DC circuit breakers for maximum current and distant faults. A traction power modeling simulation was conducted for the 1500 V DC light rail system to calculate the maximum load current in the analyzed electrical sections. It is concluded that the proposed simulation model and fault methodology can be used for DC protection settings calculations and DC circuit breaker rating analysis.

Analysis of the influence factors of VSC–HVDC on AC three-phase short-circuit current level

PurposeThis paper aims to clarify voltage sourced converter’s (VSC’s) influence rules on the alternating current (AC) short-circuit current and identify the key factors, so as to propose the short-circuit current suppression strategy.Design/methodology/approachThis paper investigates the key factors which impact the short-circuit current supplied by the VSC based on the equivalent current source model. This study shows that the phase of the VSC equivalent current source is mainly affected by the type of fault, whereas the amplitude is mainly decided by the control mode, the amplitude limiter and the electrical distance. Based on the above influence mechanism, the dynamic limiter with short-circuit current limiting function is designed. The theoretical analysis is verified by simulations on PSCAD.FindingsThe short-circuit current feeding from VSC is closely related to the control mode and control parameters of the VSC, fault type at AC side and the electrical distance of the fault point. The proposed dynamic limiter can make VSC absorb more reactive power to suppress the short-circuit current.Research limitations/implicationsThe dynamic limiter proposed in this paper is limited to suppress three-phase short-circuit fault current. The future work will focus more on improving and extending the dynamic limiter to the fault current suppression application in other fault scenarios.Practical implicationsThe research results provide a reference for the design of protection system.Originality/valueThe key influence factors are conducive to put forward the measures to suppress the fault current, eliminate the risk of short-circuit current exceeding the standard and reduce the difficulty of protection design.

Analysis of Load Flow and Short Circuit Against the Addition of Distributed Generation (DG) in Distribution Networks

This study tries to determine the level of change in short-circuit fault currents on certain buses in the Andalas University distribution network due to the installation of a new generator. Simulation of load flow and short circuit faults uses a 20 kV Andalas University distribution network system model to which a renewable generator with a capacity of 200 kW will be added. The simulation results of the load flow on a 20 kV distribution system paralleled with DG show that the voltage drop is still in accordance with the provisions of PT. PLN, this is due to the voltage drop in the distribution system is not up to 10% of the nominal 20 kV. While the short circuit simulation results, the largest single-phase and three-phase short-circuit current values occur at the Nursing_P location of 9.362 kA. However, the short circuit capacity has not yet reached a maximum voltage of 20 kV 500 MVA or 14.4 kA. So that the amount of short circuit current contributed by Nursing_P is within normal limits and does not require additional equipment to protect the fault current.

A novel time-domain method for fault detection and classification in VSC-HVDC transmission lines

The short circuit fault current is one of the worst contingencies in voltage source converter (VSC)-based high voltage direct current (HVDC) system. Therefore, having a fast, robust, and selective protection scheme is necessary in HVDC systems. In this paper, a non-communication-based protection scheme is presented using Intrinsic Time Decomposition (ITD) technique in a HVDC system. This time domain approach owns some prominent features such as high speed, low sampling rate and computational burden and no need for parameter's setting. The proposed protection scheme relies on the current signal sampled from the single end. The concept is to obtain the proper rotation component (PRC) of input signal and computing an energy index named Teager Kaiser Energy Operator (TKEO) to identify the fault occurrence in a HVDC line. The performance of the proposed scheme has been assessed against various scenarios including external disturbance such as ac faults and abrupt change of active power in two standard sample systems in MATLAB/SIMULINK and PSCAD/EMTDC environments. In addition, a wide range of internal dc faults are studied to evaluate the sensitivity of the scheme. The appropriate performance of the scheme is verified and the fault detection and classification tasks are done in less than 1 ms.

STUDI KOORDINASI SISTEM PERALATAN PROTEKSI PADA PENYULANG PIDADA UNTUK MENDAPATKAN SETTING PENGAMAN YANG SELEKTIF

An electric power distribution system must be able to provide electricity to customers. So thatthe company as a provider is required to provide the best for its customers by increasing thereliability of the distribution system. The more customers who use electricity, the greater the possiblefault current, therefore it is necessary to calculate the protection in order to minimize the occurrenceof short circuit disturbances. The protection used on the Pidada feeder is Overcurrent Relay (OCR)and Ground Fault Relay (GFR), this protection relay is used to coordinate current settings inaccordance with applicable standards and can overcome short-circuit fault currents. In this research,a study of the coordination of the Pidada feeder's OCR and GFR settings was conducted using theDigSILENT PowerFactory 15.1.7 application. Calculations were carried out using the zone divisionmethod on the feeder. based on the results of the study, it was found that the Pidada feeder was 0.2s, the Bulu Indah recloser was 0.1 s and the Padang Udayana recloser was 0.02 s. Then on and theground fault relay (GFR) obtained results on the Pidada feeder 0.2 s, Bulu Indah recloser 0.1 s andPadang Udayana recloser 0.08 using standard inverse characteristics. The results of this study arein accordance with the applicable standards, where the standard used is IEC 60255 with a dradingtime of 0.3-0.5 seconds.

System modeling and fault studies in data center power distribution

ABB&apos;s isolated parallel ring bus (IPRB) architecture with static uninterruptible power supplies (UPS) provides a solution with excellent scalability, power sharing, and fault handling capability. Critical components in a data center power distribution system are modeled for system simulations. In the modeling approach, a balance is struck between computation speed and fidelity such that useful system simulation results can be obtained for use in planning, design, and protection. The UPS model includes low short circuit current fault modes. The dual-corded load (DCL), used widely in data centers is modeled with DC link control. Transformers and chokes are modeled with saturation characteristics. Various fault scenarios have been analysed and presented. Verified system simulations in the SIMULINK modeling environment are used for fault studies to obtain protection design requirements. It is shown that system simulations with the appropriate fidelity are very useful to explore system issues and protection. Modeling the components&apos; fault mode behaviour is critical to obtain useful results.

Experimental Analysis of Flux-Coupling-Type Superconducting Fault Current Limiter Prototypes

The development of power system has increased the level of short-circuit fault current, and flux-coupling-type superconducting fault current limiter can effectively limit short-circuit current by the increased impedance after decoupling of windings. In this paper, two prototypes of pancake-winding and layer-winding were manufactured and experiments were conducted. The results show that the current-limiting ratio of two prototypes reached more than 40%. Analysis of the control strategy indicates that two breakers of the limiter could operate at the same time or at different times, and when two breakers operated asynchronously, there would be a damping direct current in the windings. When decoupled, two prototypes had coil voltage distributions of increase and then fall off, and pancake-winding had a intercoil voltage distribution of sawtooth.