Current Breaking Capacity Research Articles

Analysis of Breaking Capacity Calculation on Busbar Room Panel at PT Trias Indra Saputra

The electric panel has a function as a distribution device and as protection for electricity from the PLN. A panel must at least have protective equipment that functions so that if a fault occurs in electrical equipment, the fault can be corrected and does not interfere with the performance of the panel. In order for the protection equipment to work properly, accuracy is required in selecting the current rating and breaking capacity value of the protection components used. The purpose of this research is to analyze the breaking capacity value, nominal load current value, and short circuit current for each electrical protection component in the busbar room panel at PT Trias Indra Saputra. The analysis was carried out by comparing the results of manual calculations with calculations using the XL3-Pro calcul software, as well as the installed protection components. After calculating and comparing the results, the electrical protection components are still suitable for use as protection in the event of a fault, both short circuit fault and overcurrent on the electrical equipment in the busbar room panel at PT Trias Indra Saputra. In the outgoing protection Q0 is a protection component that connects the power source from the LVMDP panel to the busbar room panel at PT Trias Indra Saputra. Different results were obtained from the three comparisons. By using the MCCB current rating of 100A, it has been able to secure the circuit from short circuit faults and overload

Study on Short-circuit current interruption characteristics of Double-break fast vacuum circuit breaker within the minimum arcing time

It is significant for circuit breakers to expel a short-circuit fault in a short time for the new power grid with high proportional photovoltaic or wind power plants to achieve high transient operating stability. Compared with a traditional circuit breaker, a fast vacuum circuit breaker (FVCB), operated by an electromagnetic repulsion actuator, has an extremely shorter opening time and lower deviation in their opening times. This potentially contributes the FVCBs to interrupting a short-circuit fault current in the first half-wave when introducing a controlled switching technology. Meanwhile, it is beneficial to improve the short-circuit current breaking capacity of the FVCBs by adopting series-connected double-break circuit breaker technologies. This paper aims to explore short-circuit current interruption characteristics of a double-break FVCB within the minimum arcing time. We performed a series of short-circuit current interruption tests in a Weil synthetic test circuit. Two series-connected FVCBs and independent single-break FVCBs were used. Three different kinds of opening velocities were adopted for each of the FVCBs. Results showed that the increase in opening velocity resulted in both a decrease in the minimum arcing time and the critical arc extinguishing contact gap, whether for the single-break or the double-break interruption tests. The ratio of the shared voltage on each of the series-connected FVCBs was about 54 (for the break on the high-voltage side) and 9 (for the break on the low-voltage side). Taking the break with a shorter opening time as a break in the high-voltage side could reduce the minimum arcing time and the critical arc extinguishing contact gap. At the same opening velocity, the sum of the critical arc extinguishing contact gap of the two breaks in double-break interruption tests was significantly higher than twice the critical arc extinguishing contact gap in the single-break interruption tests. This could be caused by the fact that in double-break interruption tests, after the breakdown of one break, even if the break restored insulation, could not share the transient recovery voltage (TRV) before the break broke down. In addition, the sudden drop of TRV without breakdown occurred for the break on the high-voltage side might correlate with the micro-discharge of the vacuum gap. The interaction of the charged particles with the electrode surface would be responsible for the formation and evolution of the micro-discharge in some successful interruption cases.

The Influence of Novel Power System Characteristics on 330kV Power Grid Short-circuit Current

Under the development goal of “Carbon Peak, Carbon Neutralization”, the concept of novel power system is proposed. Its representative features include AC/DC interconnection of power grid and large-scale access of new energy power stations. Under these characteristics, higher requirements are put forward for the short-circuit current breaking capacity of the circuit breaker. The DC component of short-circuit current and the injection of new energy into the system short-circuit current cannot be ignored. Based on the 330kV local power grid in Northwest China, this paper studies the power grid operation mode, DC component of short-circuit current and the influence of photovoltaic power station on short-circuit current. The influence law of DC component of short-circuit current on the actual breaking capacity of circuit breaker and access of photovoltaic power station on the short-circuit current are summarized. It can provide a theoretical basis for the selection of circuit breaker in novel power system.

A Novel High-Power Hybrid DC Breaker Based on Compound Power Electronic Switch With Integrated Commutation Ability

Medium voltage dc power system has the characteristics of low line impedance, resulting in high peak and fast rise rate of the fault current. For example, the current in an onboard 10 kV dc grid can rise to more than 40 kA in 3 ms after the failure. Therefore, it is necessary to configure dc circuit breaker with high current breaking capacity. In this letter, a novel high-power hybrid dc breaker based on integrated commutation compound power electronic switch is proposed. By giving full play to the complementary advantages of insulated gate bipolar transistor (IGBT) and integrated gate-commutated thyristor (IGCT), and skillfully integrating the commutation function into the power electronic switch, the proposed dc breaker has the characteristics of low cost, compact, high performance, and can also play a role in current limiting. The working principle of the proposed scheme is described in detail, and a 10-kV prototype with 40 kA current breaking ability is built to verify its feasibility.

Switching Arc Energy Limitation Approach for LV Circuit Breakers

This paper presents an experimentally verified approach to deriving switching arc energy limitations for low-voltage (LV) circuit breakers (CBs). Air-insulated contactors equipped with additional vacuum-insulated (VI) arcing contacts were tested for AC and DC current interruption efficiency, respectively. In the study, the contact arrangements of reed relay VI contact switches of low current breaking capacity combined with air-insulated contactors were examined. Tests were performed on selected LV CBs inductively loaded for LV power network rated voltages. A comparative analysis of the arc energy resulting from various arc time durations recorded during the switching-off operation was performed. Using a variety of either basic CB air-insulated contact systems or combined contact systems, a practical assessment of the proposed idea for enhancing the arc quenching efficiency was undertaken. As a result of the implementation of the proposed idea, the arc burning duration time was indicated as being hundreds of times shorter. In most cases, a complete arc reduction was achieved. Moreover, the resulting arc energy dissipation during the breaking operation was substantially minimized. Consequently, a significant increase in the total current breaking capacity of the tested CBs was achieved.

Study of Arc Parameters of AC Relays Operating under Distorted Supply Voltage Conditions

The paper presents a procedure for measuring and analyzing the switching arc parameters occurring in air-insulated low voltage (LV) relays operating in distorted supply voltage conditions. The main purpose of the research was the analysis of the switching arc duration and its energy affecting the current breaking capacity of the selected LV current interrupters (CI). The performed study and simple statistical analysis enabled the determination of the main factors and their impact level on parameters of the switching arc that comes about during switching-off operation. Experimental tests executed for various shapes of the supply voltage but similar RMS (Root Mean Square) and THD (Total Harmonic Distortion) values and for various breaking moments of the load current allowed recognition of the decisive factors for estimating the tested relay’s switching-off capacity. Tests stand combined with dedicated software developed in the frame of the research, permiting fast calculation of the arc parameters based on a large number of recorded diagrams.

An Active Z-Source DC Circuit Breaker Combined With SCR and IGBT

SCR-based solid-state dc circuit breaker (SCR-DCCB) topologies have been widely studied for replacing the traditional expensive insulated-gate bipolar transistor (IGBT) based DCCB. Yet, the existing SCR-DCCB cannot be actively turned- off since SCR is a half-controlled device. In this letter, an active Z-source DCCB (AZ-DCCB) is proposed by the combination of IGBT and SCR. The proposed AZ-DCCB has advantages of simple and compact topology, economical design, low conduction losses, and active and bidirectional current breaking capacity. The operation process of the proposed AZ-DCCB is discussed in detail, and the designing principle of circuit parameters is also presented. Experimental results verified the effectiveness of the proposed AZ-DCCB.

Development and type test of ZW-126/D2000-40 vacuum circuit breaker with controlled switching technology

A ZW-126/D2000-40 type single-break vacuum circuit breaker(VCB) with controlled switching technology is designed and produced in this paper. The results of type test based on IEC and GB standards are presented. A 126 kV single-break vacuum interrupter (VI) with 3/4 coil axial magnetic field (AMF) contacts is used in the VCB, which can interrupt short current of 40 kA. The external insulation of the VI is provided by SF6 at 0.1 MPa. In order to match the 126kV single-break VI and controlled switching device, a long-stroke electro-magnetic force actuator (EMFA) with 16kN closing holding force and 3.5 m/s average opening speed is designed. Moreover, a position tracking controlled switching device based on closed-loop control by the technology of fuzzy control algorithm and pules width modulation is applied to the controlled switching device. This device is applied to control the coil current of EMFA and the electromagnetic force, so as to control the EMFA to follow the ideal position curve. The type tests of 126kV VCB are all passed according to the IEC62271-100 and GB1984-2014, including dielectric tests, basic short-circuit tests, short-line fault test, out-of-phase test, etc. The strong capacitive current breaking capacity and mechanical strength of the VCB are proved by the capacitive current switching test of class C2, electrical endurance test of class E2 and mechanical endurance test of class M2. The electromagnetic compatibility (EMC) tests are passed according to the IEC61000-4. The controlled switching test of capacitive current was successful according to IEC62271-302 and GB/T30846-2014, and the controlled switching accuracy is less than ±0.5 ms. The test results showed that the VCB has excellent performance, which has broad application prospects in special occasions at 126 kV voltage level, such as switching capacitor and no-load transformer, etc.

Optimal allocation of fault current limiter in MMC-HVDC grid based on transient energy flow

Economical and reliable protection of dc-side short-circuit faults has become a key technology for promoting the development of module multilevel converter based high voltage direct current grid (MMC-HVDC-Grid). The fault current limiter (FCL) can effectively suppress the rapid development of fault current and reduce the current breaking capacity of the circuit breaker. In this paper, a method based on transient energy flow (TEF) analysis is proposed to optimize the allocation of resistive and inductive FCL in MMC-HVDC-Grid. In the proposed method, the electromagnetic TEF is measured firstly, and then, the TEF suppression rate and suppression efficiency are defined as optimization objectives, and the installation place of the FCL and its impedance parameters as optimization variables. To test the proposed method, a two-terminal and four-terminal bipolar MMC-HVDC-Grids with single-pole-to-ground dc fault are modelled in the PSCAD/EMTDC so that the TEF data can be acquired. The optimal FCLs' location and parameter values are determined through investigating the evolution paradigm of TEF along with changes of FCL position and parameters. The results prove that the selected parameters can effectively slow down the dc fault current rising rate, thus reducing the requirements on tripping current of the dc breaker.

Research on Coordination and Optimal Configuration of Current Limiting Devices in HVDC Grids

This paper proposes a collaborative optimal configuration method of current limiting reactors (CLRs) and fault current limiters (FCLs) in the modular multilevel converter (MMC)-based high voltage direct current (HVDC) grids. The calculation methods of dc line fault currents and bridge arm fault currents considering the collaboration of CLRs and FCLs have high accuracy. The multi-objective optimization configuration model is established, in which the fault current limiting effect, the total inductances of CLRs and the number of FCLs are used as objective functions while the DCCBs current breaking capacity, the converter valves overcurrent protection, the boundary of the dc line protection area, the dynamic performance of the dc system and the converter station outlet dc voltage are used as constraints. In this paper, the multi-objective optimization algorithm is used to solve multi-objective optimal configuration problem for the CLRs and FCLs. Finally, the proposed method is tested with a symmetrical monopole four-terminal MMC-HVDC grid in PSCAD/EMTDC. The simulation results verify that the proposed optimal configuration method can ensure the continuous and reliable operation of the dc grid under dc faults.

Distribution of cathode current density and breaking capacity of medium voltage vacuum interrupters with axial magnetic field

A high-speed photographic technique incorporating computer-aided reconstruction of the cathode current density was applied to butt solid contacts with an external axial magnetic field (AMF) at relatively low current density j<2 kA/cm/sup 2/. In the present work, we have further developed this technique. This advanced technique is applicable for the analysis of the current density distribution on the complicated electrodes of commercial vacuum interrupters (VIs) carrying currents up to I=50 kA at current density up to j/spl sim/4 kA/cm/sup 2/. The experiments have been carried out for three types of electrode designs generating AMFs with different configurations. The results obtained by this new technique proved a previously derived conclusion that current density tends to distribute evenly across that part of the contact surface where the AMF induction fits the inequality B/sub z//sup (1)/<B/sub z/<B/sub z//sup (2)/, where B/sub z//sup (1)/, B/sub z//sup (2)/ are characteristic induction fields defined in our previous work. Results of the analysis of erosion tracks on the electrodes are also in agreement with this conclusion. Slots on the electrode surface lead to substantial nonuniformity of current density distribution even if the AMF is properly configured. Comparison of the breaking capacity and distribution of current density for different electrode designs proves that interruption failure occurs at peak current density /spl sim/3.5 kA/cm/sup 2/. This value exceeds by at least 50% previous estimates of maximum current density interruptible by a commercial VI. We have also found that changing the configuration of the AMF may substantially improve breaking capacity. In our experiments, a slight modification of the AMF distribution provides a 12% increase of the breaking capacity.

3차원 유한요소해석을 이용한 종자게형 진공 인터럽터의 특성고찰

This paper deals with the distribution characteristics of the current density and axial magnetic flux density on the vacuum interrupter with axial magnetic field type using 3 dimension finite element analysis. An axial magnetic field parallel to the current flow in the arc column can improve the current breaking capacity of vacuum interrupter by affecting the arc mode. The axial magnetic flux density on the contact electrode surface is analyzed by inputting external current as a function of the transient time for sine half wave. And it also is analyzed within the gap distance of the contact electrode. The peak value of current but is decreased with the descending current on the contact electrode surface and within the gap distance of the contact electrode. The residual magnetic field is generated on the contact electrode surface and within the gap distance in the instant of zero current, which is due to the influence of eddy currents. The phase shift due to eddy currents, defined as time difference between the maximum value of current and axial magnetic field, is about 1ms in the center point of gap distance.

Hydro-Quebec's concerns related to performances of SF/sub 6/ circuit-breakers

Hydro-Quebec's concerns regarding circuit breaker reliability are presented. Emphasis is placed on two aspects crucial in determining line charging current breaking capacity, i.e., the arc duration and the test circuit configuration. The importance of manufacturing quality for the arcing contacts, nozzles and gasket is discussed. Test criteria at 20 degrees C for simulating breaking tests at -50 degrees C are given. Hydro-Quebec's requirements for testing the tightness of SF/sub 6/ breakers are presented together with a reliable leakage-measuring method.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>