INSULATION IMPEDANCE DETECTION METHOD, APPARATUS, AND SYSTEM

Disclosed are an insulation impedance detection method, an apparatus, and a system, to reduce costs and complexity of alternating current grounding insulation impedance detection. The method includes: An inverter injects a first common-mode voltage into an alternating current side, where the first common-mode voltage is divided by an alternating current grounding insulation impedance of an alternating current cable and a direct current grounding insulation impedance of a photovoltaic unit. The inverter can obtain an impedance value of the alternating current grounding insulation impedance based on the first common-mode voltage, a voltage divided by the alternating current grounding insulation impedance for the first common-mode voltage (a second common-mode voltage on the alternating current grounding insulation impedance), and an impedance value of the direct current grounding insulation impedance. The alternating current grounding insulation impedance is detected by using a necessary device, namely, the inverter in a photovoltaic power generation system. In this way, an additional detection device is not mounted, which reduces costs and complexity of alternating current grounding insulation impedance detection. Also, the method is compatible with various photovoltaic power generation systems with an inverter, which improves commonality of the alternating current grounding insulation impedance detection method.