US 11,909,353 B2
Ground-fault detecting device and related method
Chunbao Zeng, Xiamen Fujian (CN); Peizai Hong, Xiamen Fujian (CN); Wen Wei, Xiamen Fujian (CN); Zhenhuang Lin, Xiamen Fujian (CN); and Kailong Chen, Xiamen Fujian (CN)
Assigned to KEHUA HENGSHENG CO., LTD., Xiamen Fujian (CN)
Filed by KEHUA HENGSHENG CO., LTD., Xiamen Fujian (CN)
Filed on Sep. 8, 2022, as Appl. No. 17/940,743.
Application 17/940,743 is a continuation of application No. 16/556,230, filed on Aug. 30, 2019, granted, now 11,469,708.
Prior Publication US 2023/0006605 A1, Jan. 5, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. H02S 50/00 (2014.01); G01R 31/50 (2020.01); H02J 3/38 (2006.01); H02J 3/00 (2006.01)
CPC H02S 50/00 (2013.01) [G01R 31/50 (2020.01); H02J 3/0012 (2020.01); H02J 3/381 (2013.01); H02J 3/388 (2020.01); H02J 2300/24 (2020.01)] 12 Claims
OG exemplary drawing
 
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.