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This post was last edited by liwei618 on 2020-2-19 at 18:33. Based on the characteristics of arcs that occur when faults arise inside switchgear, and by taking into account the criteria related to sudden changes in current at the power supply point during faults, an arc protection system is developed. This system provides fast and reliable protection, has a simple configuration, and offers good adaptability; it represents an ideal solution for busbar protection at present. Currently, some substations use arc flash protection to provide rapid primary protection for switchgear rooms. Both the switchgear rooms and cable rooms fall under the scope of busbar protection. However, the principle of arc flash protection relies on current fluctuations and arc flash detection criteria; it is not possible to determine whether a fault occurs below or above the location where the CT is installed. Since the area below the CT can be protected through feed unit protection to ensure rapid response, arc flash monitoring points are generally not installed due to considerations related to selectivity. Yet, switchgear rooms and cable rooms are areas where faults tend to occur, resulting in protection coverage gaps. To address this issue, this system offers an arc light protection mechanism based on a new principle, which enables selective tripping at the location where a fault occurs inside the switchgear, thus providing comprehensive and rapid protection against faults within the switchgear. Arc protection devices provide 100% rapid protection against internal faults in switchgear. As a comprehensive protection solution for medium- and low-voltage switchgear, they feature fast response times and the ability to identify the location of faults. If a fault occurs below the circuit breaker, the circuit breaker itself trips to eliminate the fault; if a fault occurs above the circuit breaker, the switch at the busbar power supply point is activated to isolate the fault. This ensures that the time required to eliminate faults in each compartment of the switchgear is minimized. Before a arc fault occurs and the pressure and temperature inside the cabinet rise sharply, the protection system can issue a trip command to cut off the short-circuit current in the system. This minimizes damage to equipment and injuries to personnel, protects expensive main transformers or station service transformers from being damaged by excessive short-circuit currents, prevents the impact from spreading to the station’s DC system, and thereby avoids economic losses caused by the escalation of accidents. The protection system ensures the safety of operators, minimizes losses caused by failures, and creates the conditions necessary for rapid fault resolution and power restoration. After a arc fault occurs in the system, equipment that relies on the proper operation of the arc protection system can be put back into use after maintenance, thereby reducing equipment losses. Arc protection features low cost, fast speed, and a simple principle; the entire system is easy to install and convenient to construct, making it an ideal solution for protecting medium and low voltage busbars and feeders. Product features of the switchgear arc protection device: The 9805 is a modular system comprising a main control unit (9805-1), current units (9805-2), arc expanders (9805-3), arc units (9805-4), arc relay expanders (9805-5), and arc relays (9805-6). The main control unit 9805-1 serves as the core component of the arc protection system; it is responsible for acquiring, measuring, calculating, and performing logical judgments on input signals. It also implements all protection functions of the system, communicates with the substation monitoring system, performs self-diagnostics, and provides other auxiliary functions. The protection device chassis features a unique front-mounted and rear-inserted design: the CPU board is mounted at the front, while other components are inserted from the back. The CPU component is positioned perpendicular to the other components, which allows for complete separation between high-voltage and low-voltage circuits, thereby enhancing the device’s resistance to interference ； The main control unit 9805-1 features arc protection for switchgear and breaker failure protection. The main control unit can be equipped with either 2 Ethernet ports or 2 CAN ports. Its communication protocol complies with the nationally mandated IEC60870-5-103 standard, enabling easy integration into the substation’s integrated automation system. The main control unit itself has 6 regular relay outputs, 2 fast relays, 5 signal contacts, and 16 digital input contacts. The arc protection devices for 9805 switchgear produced by our company are inexpensive, of reliable quality, and highly favored by users. If you would like to know about the range settings for arc flash bus protection devices or how to handle alarms from such devices, please contact our technical staff. We will promptly assist you in resolving any technical issues related to arc flash protection devices in switchgear. This article is sourced from: http://www.weijizongbao.com/jishu/571.html