A box-type substation, an energy storage power supply system, and a photovoltaic power generation system. The box-type substation includes a low-voltage cabinet, a high-voltage cabinet, a transformer, a first keychain, and a second keychain. When two circuit breakers in the low-voltage cabinet are in a switched-on state, each of the first keychain and the second keychain is locked at a corresponding circuit breaker. Therefore, when maintenance is performed on the transformer, the circuit breakers in the low-voltage cabinet are switched off first to remove the first keychain and the second keychain. Then, the first keychain and the second keychain are used together to switch off a disconnector in the high-voltage cabinet, and the first keychain and the second keychain are locked at the disconnector when the disconnector is in a switched-off state. Mechanical lock logic of the box-type substation is simple with high efficiency.

An submarine cable system includes a first and a second submarine cable circuit branches arranged in parallel between an onshore BSP and an offshore BSP, and a first and a second bus reactor circuits arranged in parallel and connected to the onshore BSP. The first and second submarine cable circuit branches each includes a first circuit breaker, a submarine cable circuit, and a second circuit breaker connected in series, a first line reactor of which one end is grounded and another end is connected between the submarine cable circuit and the first circuit breaker, and a second line reactor of which one end is grounded and another end is connected between the submarine cable circuit and the second circuit breaker. The first and second bus reactor circuits each includes a bus reactor and a circuit breaker connected in series. An example switching method for this system is also disclosed.

A box-type substation, an energy storage power supply system, and a photovoltaic power generation system. The box-type substation includes a low-voltage cabinet, a high-voltage cabinet, a transformer, a first keychain, and a second keychain. When two circuit breakers in the low-voltage cabinet are in a switched-on state, each of the first keychain and the second keychain is locked at a corresponding circuit breaker. Therefore, when maintenance is performed on the transformer, the circuit breakers in the low-voltage cabinet are switched off first to remove the first keychain and the second keychain. Then, the first keychain and the second keychain are used together to switch off a disconnector in the high-voltage cabinet, and the first keychain and the second keychain are locked at the disconnector when the disconnector is in a switched-off state. Mechanical lock logic of the box-type substation is simple with high efficiency.