Ring Main Unit (RMU) assembly and testing line

Component Assembly

1. Frame Assembly: Begin by assembling the metal frame of the RMU according to the design drawings and specifications. Ensure all connection points are secure and meet the standards for structural strength and stability.
2. Busbar Installation: Install the busbar system into the cabinet and ensure it is properly aligned and secured. Busbar connections should be smooth, clean, and tightened according to electrical specifications.
3. Circuit Breaker and Switch Installation: Mount the circuit breakers and other switching devices in their designated locations, ensuring they operate smoothly without obstruction.
4. Grounding and Isolating Switch Installation: Install grounding and isolating switches, ensuring they are correctly connected to the busbars and circuit breakers with flexible operation.
5. Cable Connection: Connect cables to the input and output ends of the RMU, ensuring all cable connections are correct and securely fixed with appropriate protective measures.
6. Protection and Monitoring Device Installation: Install protective devices such as fuses, surge arresters, and monitoring devices like relays and meters, ensuring they are correctly connected according to the wiring diagram.
7. Operating Mechanism and Control Panel Installation: Install the operating mechanism and control panel, ensuring they can control all functions of the RMU and that indicator lights and displays are functioning properly.
8. Enclosure and Door Installation: Install the enclosure and doors of the cabinet, ensuring all seals are intact to provide protection against dust, moisture, and other environmental factors.

Testing Procedures

1. Visual Inspection: Conduct a comprehensive visual inspection of the assembled RMU to ensure no steps have been omitted and all components are correctly installed in place.
2. Electrical Testing: Perform a series of electrical tests, including insulation resistance testing, ground resistance testing, and continuity testing, to ensure all electrical connections are safe and reliable.
3. Functional Testing: Test all operational functions of the RMU, including the opening and closing operations of the circuit breakers, the flexibility of the grounding and isolating switches, and the functionality of the control panel.
4. Withstand Voltage Testing: Conduct withstand voltage testing on the RMU to verify its ability to withstand specified working voltages and transient overvoltages.
5. Protection Device Testing: Test all protective devices to ensure they operate correctly under abnormal conditions, such as overloads, short circuits, and overvoltages.
6. System Integration Testing: If the RMU is part of an automated system, perform system integration testing to ensure seamless connectivity with the control system.
7. Field Simulation Testing: If possible, conduct field simulation testing to simulate real operating conditions and ensure the RMU’s performance in actual use.