Digital Overvoltage / Low Voltage Relay Method of Electronic Switchboard

摘要

The digital overvoltage / undervoltage relay method of the electronic switchboard of the present invention prevents the load from being damaged by interrupting the power supply after a predetermined time according to the degree of overvoltage and undervoltage when the overvoltage and undervoltage are supplied to the load, Although the analog type protective relays such as iron-core type relays, induction type relays and static type relays were used, it is very difficult to set the operation level to evolve, and it is required not only skill but also a lot of time, The operation level has to be set again. In addition, according to the degree of the overvoltage and the undervoltage, the shutdown delay time of the power supplied to the load can not be accurately set, and the response speed is slow to protect the load.;In the invention, the shutdown delay time of the power supply according to the degree of the overvoltage and the undervoltage is preset and stored in the lookup table within the range that does not damage the load during overvoltage and undervoltage, and the voltage level supplied to the load And the sampled data is calculated to determine a voltage level between each phase and a peak voltage and a peak voltage. The determined maximum voltage and minimum voltage are compared with a rated reference voltage to calculate an overvoltage ratio and a low voltage ratio, If the overvoltage and undervoltage conditions continue for the cutoff delay time after reading the cutoff delay time according to the calculated overvoltage ratio and low voltage ratio, the overvoltage and undervoltage are prevented from being supplied to the load by cutting off the power supply. When supplied, the power is shut off correctly after the cut-off delay time according to the self-voltage ratio and the low voltage ratio When the load is not damaged and the level of the overvoltage and the low voltage is set at the time of installation or replacement of the load, it is necessary to simply change the rated reference voltage, so that the operation is very simple and the work time is shortened. If there is a momentary voltage fluctuation within the range, the power can be continuously supplied to the load for operation.