Scope of Application
The QKM7L series residual current operated circuit breakers (hereinafter referred to as the circuit breakers) are products independently developed by our company to meet the demand for residual current reclosing function in urban and rural power grids and other various applications. This series of circuit breakers is applicable to the low-voltage three-phase four-wire power grids with neutral point directly grounded, featuring AC 50Hz, rated voltage 400V and rated insulation voltage 1000V. The circuit breakers cover three frame sizes of 250A, 400A and 630A, with the rated current ranging from 50A to 630A and the rated residual operating current from 50mA to 800mA.
It integrates multiple protection functions including overload protection, short-circuit protection, residual current protection, overvoltage protection, undervoltage protection, phase loss protection, sudden change protection, special wave protection, neutral loss protection and lightning protection, as well as the reclosing function. The product line is extended to include the external circuit breaker series for prepayment electric energy meters.
The circuit breakers comply with the following standards: GB/T14048.2 Low-voltage switchgear and controlgear – Part 2: Circuit breakers; GB/T 32902 Residual current operated circuit breakers with automatic reclosing function (CBAR); Q/GDW1365 Technical Specification for Information Exchange and Security Authentication of Smart Electric Energy Meters.