Patent ID: 11909353
Assignee: KEHUA HENGSHENG CO., LTD.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  G  Y | IPC G  H

Claim 0:
1. A ground-fault detecting device, comprising:
a first detecting module, having a first input terminal, a second input terminal, and a third input terminal coupled to a first-phase electric power, a second-phase electric power, and a third-phase electric power on an AC (Alternating Current) side of a photovoltaic power generating system respectively, for sampling voltages of the first-phase electric power, the second-phase electric power, and the third-phase electric power to generate a first sampled voltage, a second sampled voltage, and a third sampled voltage respectively; and
a controller, coupled to the first detecting module, for determining if a ground-fault occurs in the AC side before the photovoltaic power generating system is connected to a grid according to the first sampled voltage, the second sampled voltage, and the third sampled voltage;
wherein the controller generates an alarm signal when the ground-fault occurs in the AC side, wherein the first detecting module comprises:
a first matching impedance device, having a first terminal coupled to the first-phase electric power;
a first grounding resistor, having a first terminal coupled to a second terminal of the first matching impedance device, and a second terminal coupled to a ground;
a second matching impedance device, having a first terminal coupled to the second-phase electric power;
a second grounding resistor, having a first terminal coupled to a second terminal of the second matching impedance device, and a second terminal coupled to the ground;
a third matching impedance device, having a first terminal coupled to the third-phase electric power;
a third grounding resistor, having a first terminal coupled to a second terminal of the third matching impedance device, and a second terminal coupled to the ground;
wherein the first sampled voltage is a voltage difference between the first terminal and the second terminal of the first grounding resistor; the second sampled voltage is the voltage difference between the first terminal and the second terminal of the second grounding resistor; the third sampled voltage is the voltage difference between the first terminal and the second terminal of the third grounding resistor.