DC Circuit Research Articles

Detection of opening motion characteristics in DC circuit breakers based on machine vision.

A circuit breaker is a crucial component in power systems, and its operation is essential for evaluating its interruption performance. However, electromagnetic interference often affects sensor accuracy. To address this issue, this paper investigates a non-contact measurement technique for assessing the motion characteristics of circuit breakers. A motion detection method based on Franklin moments is proposed. A synchronous image acquisition platform was established using high-speed cameras to capture the motion of 252kV circuit breakers. The captured images are preprocessed, with coarse edges extracted using the Laplacian algorithm. Franklin moment convolution calculations are then applied to determine sub-pixel coordinates of the image edges based on these coarse edges. By analyzing the frame-to-frame variations of these sub-pixel coordinates, the opening motion characteristics of the circuit breaker are extracted. This method can detect the vibration parameters and bouncing phenomenon of circuit breaker motion machine in millisecond level, and the accuracy is 0.01 mm. These findings offer valuable insights for future research on circuit breaker performance.

An Efficient Hybrid DC Circuit Breaker With Mechanical and Power Electronics Based on Current Commutation

An Efficient Hybrid DC Circuit Breaker With Mechanical and Power Electronics Based on Current Commutation

A novel model of superconducting tape-based hybrid DC circuit breaker for monopolar and bipolar HVDC grid

A novel model of superconducting tape-based hybrid DC circuit breaker for monopolar and bipolar HVDC grid

Fault current handling in large-scale MMC-HVDC systems: an improved approach with DC circuit breaker and fault current limiter

Fault current handling in large-scale MMC-HVDC systems: an improved approach with DC circuit breaker and fault current limiter

Multi-terminal flexible DC grid circuit breaker withstands multi-lightning strike analysis

Lightning represents the primary threat to power grids, with approximately 80% of natural occurrences being multi-lightning strikes, which have been extensively studied and confirmed to pose even more severe hazards. Hybrid DC circuit breakers (DCCBs) exhibit promising application prospects due to their superior interruption performance. During multi-lightning strikes, lightning intrusive waves pose a greater threat to the insulation of equipment such as hybrid DC fuses, fast mechanical switches, and insulated gate bipolar transistors. Therefore, this paper establishes a simulation model using the Real-Time Digital Simulator based on the model and parameters of the DCCB in the ± 500 kV Zhangbei HVDC project in China. It analyzes the lightning intrusive waves on the DCCB and investigates the energy absorption of metal oxide varistors (MOVs) in the energy-consuming branch of the DCCB under multi-lightning strikes, as well as the overvoltage levels of various branches of the DCCB under such conditions. The research results indicate that the energy-consuming branch has a certain tolerance to multi-lightning strikes. However, if the MOV collapses under multi-lightning strikes, it can lead to severe overvoltage issues. Therefore, the design and selection of DCCBs should fully consider the impact of multi-lightning strikes.

A novel mechanical DC circuit breaker with adaptive reclosing ability

A novel mechanical DC circuit breaker with adaptive reclosing ability

Multiobjective Optimization of Key Parameters for the Chamber of Low-Voltage DC Circuit Breakers Based on MHD

Multiobjective Optimization of Key Parameters for the Chamber of Low-Voltage DC Circuit Breakers Based on MHD

Optimization study of the 100-us-level mechanical switch for natural commutation DC circuit breaker

Optimization study of the 100-us-level mechanical switch for natural commutation DC circuit breaker

SF6 DC circuit breaker and its fault isolation method in half-bridge MMC system

SF6 DC circuit breaker and its fault isolation method in half-bridge MMC system

Investigation of the Electromagnetic Force and Contact Spring in Rotational Ultra-Fast Disconnector in Railway DC Circuit Breaker

Investigation of the Electromagnetic Force and Contact Spring in Rotational Ultra-Fast Disconnector in Railway DC Circuit Breaker

Mechanism and suppression of breaking overvoltage of DC circuit breakers

AbstractThe occurrence of breaking overvoltage in a DC circuit breaker (DCCB) poses a potential threat to the safe operation of a DC grid. Based on the structure of the ±10 kV three‐terminal DC distribution network, this paper sets up the medium‐voltage DCCB and formulates a fault protection strategy. Additionally, a simulation model of the system is developed to analyse the overvoltage characteristics within the DC distribution network across different nodes and fault conditions. By examining the factors that influence breaking overvoltage, this paper unravels the fundamental mechanisms associated with DCCB‐related overvoltage generation. Furthermore, the paper suggests measures to alleviate DCCB overvoltage. These insights provide a theoretical and technical basis for the design and operation of DCCBs within DC distribution networks.

A novel thyristor‐based hybrid DC circuit breaker with short arcing capability

AbstractMulti‐terminal flexible high‐voltage direct current (HVDC) transmission and DC grid technology are developing rapidly. The hybrid DC circuit breaker (HCB) has broad application prospects in the field of HVDC transmission and DC power grid. Nevertheless, existing HCBs have one or more following blemishes: arc suppression scheme of mechanical switch, high cost and unreliable adaptive reclosure. In this paper, a modified thyristor‐based hybrid DC circuit breaker with short arcing capacity (SA‐HCB) is introduced, which consists of the main branch, the fault handling branch and the pre‐charging branch. Besides, the modified SA‐HCB has the inherent capability of adaptive reclosing. The advantages of thyristors are fully used in the SA‐HCB, such as low cost, low conduction voltage drop, and natural shutdown. The detailed structure diagram and mathematical model of the SA‐HCB are introduced, and the operation processes of the fault current transfer are also analysed. Later, a design method for parameters of the proposed SA‐HCB is provided. Then, a single‐ended equivalent system is built in PSCAD/EMTDC to verify the accuracy of the theoretical analysis and parameter design. Subsequently, based on four‐terminal simulation, the economy of the SA‐HCB is verified by comparing with the topology proposed by ABB. Finally, the small‐scale experiment of the proposed SA‐HCB is introduced.

Topology and Control of Multiport DC Circuit Breaker Integrating Current-Limiting and Fast Fault Clearing Capabilities

Topology and Control of Multiport DC Circuit Breaker Integrating Current-Limiting and Fast Fault Clearing Capabilities

АСИНХРОННІ ГЕНЕРАТОРИ В АВТОНОМНИХ ДЖЕРЕЛАХ ЖИВЛЕННЯ ЗВАРЮВАЛЬНОЇ ДУГИ. СТАН І ПЕРСПЕКТИВИ

The article is aimed at generalizing the results of the study of asynchronous generators (AG) of autonomous welding arc power sources (AWPS) obtained in the Department of Electromechanical Systems of the Institute of Electrodynamics of the NASU. The proposed classification of AG of autonomous welding systems is considered, mathematical models are developed, the results of computational and experimental studies of such systems with AG with capacitor excitation and an uncontrolled rectifier, in the DC circuit of which high-frequency inverters, pulse-width regulators or half-bridge inverters are connected, as well as generators with valve and valve-capacitor excitation. The design features and experimental samples of welding arc power sources with AG are considered. The directions of further research are determined. Ref. 42, fig. 5.

Study of IGCT Based Superconducting Hybrid DC Circuit Breakers in Subway DC Traction Power Supply System

Study of IGCT Based Superconducting Hybrid DC Circuit Breakers in Subway DC Traction Power Supply System

Study on Coordination of Different Types of DC Superconducting Current Limiter and DC Circuit Breaker for Electric Propulsion Aircraft

Study on Coordination of Different Types of DC Superconducting Current Limiter and DC Circuit Breaker for Electric Propulsion Aircraft

Hybrid DC circuit breaker power supply system with load constant voltage self‐balancing design

AbstractPower electronic switches (PES) play a crucial role in transferring and clearing fault currents in hybrid DC circuit breakers. The PES encounters switching transients that require a dependable external power source. Usually, a power supply system utilizes an isolation transformer and many magnetic rings. However, the existence of inconsistent parameters might easily cause an imbalance in load power, which could potentially result in power supply failure for the loads. Therefore, to enhance the reliability of power supply, this study proposes a load constant voltage self‐balancing design approach that utilizes feedback circuits to achieve stability and balance in load voltage. At first, two feedback circuits are shown, and the analytical formulas for load active power and load voltage are derived. Moreover, a parameter design methodology is shown for the equivalent circuit of the magnetic rings in the power supply. Additionally, a power supply system is built with 24 V outputs. In conclusion, this study utilizes simulations and tests to assess the effectiveness of the proposed power supply system by analysing its performance during start‐up, load power‐off, and steady‐state operations.

A fault detection and location algorithm for the LVDC interconnection network in rural area

AbstractLow voltage DC (LVDC) microgrids (MGs) can be linked together through an interconnection network to enhance the utilization of their energy resources in remote locations, particularly in rural low‐income areas. However, the identification of the fault is challenging due to the fast fault transients and equipment limitations, where there are no sensors and DC circuit breakers (DCCBs) in the lines. To solve this problem, this article proposes a fault detection and location algorithm without requiring extra sensors and DCCBs in lines. The proposed algorithm uses the sensors of the interface converters to detect the fault. Following this, a coordinated current injection method is used to identify the faulty element by coordinating converters with disconnectors. This process employs two strategies “weight check” and “scope check” to minimize the time and the number of actions. The algorithm is robust to various fault impedance, fault types and network topology modifications. The effectiveness of the algorithm is validated through a series of simulation case studies.

Osprey optimization algorithm for MPPT of PV system with forward DC to DC converter under partial shading conditions

Abstract Electric power is required anywhere for multiple purposes to do various tasks. Production of electricity from renewable sources such solar energy is feasible solution for many problems. Photovoltaic modules are generally used to produce electricity through solar irradiance. However, a maximum power point tracking device (MPPTD) must be incorporated to Photovoltaic system to ensure its maximum utilization or best efficiency. A forward DC to DC circuit is selected to work as MPPTD in this paper. Many conventional algorithms including incremental conductance, perturb & observe are available to work effectively for MPPTD under uniform solar irradiances. However, non-uniform irradiances will be received by Photovoltaic modules where many are connected to form a power generation system due to trees, shading, dust, birds, clouds, etc Such phenomenon drags the system into Partial Shading Condition (PSC). Under PSC, conventional algorithms cannot identify the best location to harvest more energy. Hence, an optimization technique is required to operate Photovoltaic system at its outfit utilization during PSC. An optimization technique namely ‘Osprey Optimization Algorithm (OOA)’ is developed in this paper on MPPTD to harvest more energy during PSC. The comparison among OOA, Grey Wolf Optimization (GWO), Modified Invasive Weed Optimization (MIWO) and Whale Optimization Algorithm (WOA) is also included in this paper. The Hardware—in the—Loop is establish by using OPAL-RT technology to collect various results for presenting analysis under different operating conditions.

Development of a novel full thyristors hybrid DC circuit breaker combining vacuum and gas integrated series switch

In order to accelerate the fault current transfer rate of hybrid DC circuit breaker (HDCCB) and reduce the cost. A novel full thyristors HDCCB combining vacuum and gas integrated series switch is proposed in this paper, which accelerates the fault current transferred. Moreover, the breaking of higher current levels and lower cost by using the full thyristors to replace the IGBT and other power electronic (PE) devices are realized. The operation of proposed HDCCB is analyzed in detail, and the theoretical numerical model is derived. With the key parameters optimized in terms of the operation HDCCB, the breaking current capability and the effectiveness are verified by the simulation model. Based on this, preliminary tests from a developed low-power prototype are presented and verified the performance of the proposed novel HDCCB.