1. Introduction VVVF control, due to its advantages such as high efficiency, energy saving, and precise control, has been widely used in industrial fields, especially in electrical equipment. The elevator industry adopted VVVF control relatively early, and it is now almost universally used in elevators. Its advantages are well-known. However, in principle, this type of control system still suffers from leakage current and high-order harmonics. This leakage current, flowing to ground through parasitic capacitance, consists only of the high-frequency component. This is fundamentally different from the power frequency leakage current caused by poor insulation or short circuits, which flows directly to ground. Similar to thyristor-controlled elevators, this power frequency leakage current is also very small. Since the leakage current contains both high-frequency and power frequency components, leakage current circuit breakers, leakage current relays, or leakage alarms can be used to detect whether it includes the high-frequency leakage current generated by the frequency converter. 2. Setting Values ​​for Leakage Current Circuit Breakers or Leakage Alarms For elevators controlled by frequency converters, in addition to using leakage current circuit breakers or leakage alarms corresponding to the frequency converter, the current reference should be set for each elevator according to the following sensitivity settings. When the technical standards for electrical equipment, occupational safety regulations, etc., specify the rated operating current, each elevator must be equipped with a leakage current circuit breaker or leakage alarm. [b][align=center]For details, please click: Leakage Current and High-Order Harmonic Problems and Solutions in VVVF-Controlled Elevators[/align][/b]