This document applies to the technical requirements for the design, testing, supply, installation, and related supporting equipment (sensors, controllers, cables, etc.) of Ring Main Units on Electric Du Cambodge in 22kV 50Hz HV Switchgear.
ROCKWILL 22kV Ring Main Unit is engineered to fully comply with EDC-DTS-MV003 specification for Cambodia’s 22kV underground distribution network. Rated equipment voltage 24kV, nominal system voltage 22kV, rated continuous current 630A, rated short-time withstand current 20kA / 25kA for 3 seconds. The RMU adopts modular metal-enclosed compact structure; gas-insulated version uses welded stainless steel gas tank with IP67 gas compartment, or optional air/vacuum SF₆-free design. Equipped with mandatory mechanical five-prevention interlock, supports manual operation with motorized actuator and RTU/ SCADA interface for distribution automation. Type tests follow IEC 62271 series standards plus EDC mandatory witness test including internal arc test. Designed for tropical high humidity environment, expected service life 25 years, widely used in Phnom Penh and provincial underground cable distribution projects of EDC.