Description
Functional Features Comprehensive Protection Function: It is mainly used for selective, reliable and fast differential protection of busbars, T-shaped connections and mesh corners. It can protect various busbar configurations such as single busbars, double busbars (with or without transfer busbars), double circuit breakers or one-and-a-half circuit breaker substations. In addition to differential protection, it also includes a flexible dynamic zone selection (isolator duplication) function, integrated in an intelligent electronic device (IED). Advanced Communication Capability: Designed in compliance with the IEC 61850 standard, it implements all aspects of this standard, ensuring an open, future-oriented and flexible system architecture. It supports multiple communication protocols, such as IEC 61850, Profibus, DNP 3, etc., and has flexible communication options, enabling convenient communication and data exchange with other devices. Event Recording and Analysis: Equipped with a comprehensive event recorder, it can record relevant events and data, facilitating fault analysis and system maintenance. Easy to Use and Configure: It provides easy-to-use setting tools, making it convenient for engineers to configure and debug, reducing on-site working time and difficulty.
Technical Parameters Electrical Parameters: The operating voltage supports a wide voltage range of 24 - 265V AC/DC, adapting to the requirements of different power systems. Communication Parameters: It supports communication protocols such as IEC 61850, Profibus, DNP 3, etc., and can achieve high-speed and reliable data transmission with other devices. Operating Environment: The operating temperature range is generally from -40°C to +85°C, which can adapt to various harsh industrial environments and ensure stable operation under different temperature conditions. Dimensions and Weight: The dimensions are approximately 100mm×80mm×40mm, and the weight is 1.5kg. Protection Range: It can be used to protect busbar systems from medium voltage to extra-high voltage levels. There are up to 6 protection zones, and it can provide fast and accurate protection against various internal faults such as phase-to-phase faults, ground faults and multi-phase faults. The busbar protection principle of ABB REB670 1MRK002820-AC is mainly based on current differential protection, according to Kirchhoff's current law: During Normal Operation and External Faults: When the power system is operating normally or a fault occurs outside the busbar, according to Kirchhoff's current law, the current flowing into the busbar is equal in magnitude and opposite in direction to the current flowing out of the busbar, and their algebraic sum is zero, that is, the differential current of the busbar differential protection is zero, and the busbar protection does not operate at this time. When a Busbar Fault Occurs: When a busbar fault occurs, an additional current will appear at the fault point, causing the current flowing into the busbar and the current flowing out of the busbar to be no longer balanced, and the differential current is no longer zero. If this differential current is greater than the operating current value set by the busbar protection, the busbar protection device will determine that a busbar fault has occurred, and then quickly issue a tripping command to trip all the circuit breakers on the busbar to remove the fault, prevent the expansion of the fault, and protect other parts of the power system from being affected by the fault.
In order to improve the reliability and sensitivity of the busbar differential protection, REB670 may also adopt some auxiliary criteria and technologies, such as:
Ratio Restraint Characteristics: Adopting the principle of ratio differential protection, the primary through-current is used as the restraint current, so that the operating current of the busbar protection changes with the change of the restraint current. When a fault occurs outside the busbar area, although an unbalanced current may occur due to the saturation of the current transformer (CT), since the current on the fault branch increases, the restraint current also increases, which can provide a strong restraint ability and prevent the protection from malfunctioning.
Coordination of Total Differential and Sectional Differential: The differential circuit of the double busbar connection includes the total differential circuit of the busbar and the sectional differential circuits of each section of the busbar. The total differential of the busbar refers to the differential circuit composed of the currents of all branches except the bus tie switch and the sectional switch. The sectional differential of a certain section of the busbar refers to the differential circuit composed of the currents of all branches connected to this section of the busbar, including the bus tie and sectional switch currents. The total differential is used as the starting element to judge the fault within the area, and the sectional differential is used as the selection element to judge which busbar the fault is on.
