1 . A Photovoltaic High-Voltage Ring Main Unit (PV HV RMU) is a specialized type of medium-voltage switchgear designed for solar power plants (photovoltaic systems). It plays a crucial role in the collection, protection, and distribution of electrical power generated by PV inverters before it is stepped up and sent to the grid.

✅ Definition:

A Photovoltaic High-Voltage Ring Main Unit is:

A compact, sealed, and insulated medium-voltage (typically 11kV–36kV) switchgear unit used in solar farms to connect multiple PV inverter outputs, ensure safe power flow, and provide protection and switching in a ring network configuration.

2.🔧 Key Functions:

1. Connect multiple sources: Links several transformer outputs (from PV inverters) into a ring network.

2. Switching & Isolation: Safely disconnect sections of the solar plant for maintenance or fault isolation.

3. Protection: Integrated with circuit breakers or load break switches and protection relays.

4. Grid interface: Acts as the interface before power is sent to the main substation or transmission grid.

3.📦 Key Features:

4.🏗️ Application in Solar Power Plants:

1. PV modules → Inverters → Step-up transformer (LV to MV) → RMU → Main substation

2. Multiple RMUs can be linked in a ring to maintain continuous operation even if one unit is offline.

3. The RMU ensures fault isolation, minimizing system downtime.

5.🔁 Ring Main vs. Radial Configuration:

A PV High-Voltage Ring Main Unit is essential for:

• Safe switching and protection in solar farms

• Efficient power collection at MV level

• Reliable grid connection with minimal downtime

Would you like help choosing between RMU types for your PV project, or comparing SF₆ vs. solid-insulated RMU ?