SRMU — 12 kV solid epoxy insulated RMU monoblock
SRMU is a 12 kV ring main unit monoblock with solid epoxy insulation HCEP and vacuum interrupters, without SF6. Modular design of circuit breakers, load break switches and fuse switches, withstand 20 kA for 3 s, manual or motorized control from SCADA.
- Rated voltage
- 12 kV
- Modules
- load break switch (SW), vacuum circuit breaker (CB), fuse switch (200 A)
- Short-time withstand current
- 20 kA, 3 s
- Making capacity
- 52 kA
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
SRMU (Solid Insulated Ring Main Unit) operates in underground cable distribution networks of the 12 kV class. The design is modular and expandable. The monoblock is assembled from vacuum circuit breaker (CB), load break switch (SW) and fuse switch modules in the required configuration and can later be extended with a busbar extension kit. The model was developed in 2012–2013, and the tests were carried out by KERI.
All internal parts are insulated with hydrophobic cycloaliphatic epoxy resin HCEP. There is no SF6 in the monoblock, so gas leakage and explosion are excluded, and the manufacturer calls this design clean and green. The circuit breaker has a pre-charged spring drive and can perform auto-reclosing. The load break switch and the fuse switch are equipped with a toggle spring drive. The mechanisms have few parts, which extends service life, and the vacuum interrupters break current without maintenance of the arc-extinguishing medium.
The main switch and the earthing switch are separate and mutually interlocked. During maintenance double protection applies, the earthing switch together with the disconnector. The IP55 enclosure protects the mechanism from external influences, each circuit has a voltage presence indicator, and the contact position is visible on the mimic diagram. Cables are connected with T-type plug-in connectors.
Rated voltage is 12 kV, frequency 50/60 Hz. Short-time withstand current is 20 kA for 3 s, making capacity 52 kA, impulse withstand voltage 85 kV, the same for the load break switch, circuit breaker and fuse modules. The fuse module is rated for 200 A, and its breaking current is limited by the fuse itself. Service life is 2000 operations.
The manual version is equipped with the self-powered protection relay ETR20/H with functions 51, 50, 51N, 50N and 1 A CTs. The motorized version receives the multi-circuit relay ETR304/306, which measures, monitors and records parameters and transmits them to SCADA over DNP 3.0, MODBUS and IEC 60870-5-101/104. KERI carried out the type tests to IEC 62271-100, 102, 103, 105 and 200. SRMU is installed in cable networks of cities and industrial zones, at transformer substations and for connecting wind turbines, and the Korean catalog explicitly describes it as an RMU for wind farms.
Technical specifications
| Rated voltage | 12 kV |
|---|---|
| Modules | load break switch (SW), vacuum circuit breaker (CB), fuse switch (200 A) |
| Short-time withstand current | 20 kA, 3 s |
| Making capacity | 52 kA |
| Impulse | 85 kV |
| Service life | 2000 operations |
| Insulation | HCEP, IP55 enclosure |
| Control | ETR20H (self-powered relay) or ETR304/306 (motorized, SCADA) |
| Connection | T-type plug-in adapters |
| Standards | IEC 62271-1, -100, -102, -103, -105, -200, IEC 60255, IEC 60529 |
Request a price and lead time
SRMU — 12 kV solid epoxy insulated RMU monoblock. We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Customs codes
| UKTZED (Ukraine) | 8537 20 91 00 |
|---|---|
| HS, 6 digits | 8537 20 |
| CN (EU) | 8537 20 91 |
| HTSUS (USA) | 8537 20 00 00 |
| China customs tariff | 8537 20 90 00 |
Codes are for reference: the final code is determined at declaration for the specific model.
Questions and answers
Which modules does SRMU consist of?
The monoblock is assembled from vacuum circuit breaker, load break switch and 200 A fuse switch modules. The set is extended with a busbar extension kit.
What withstand currents does the 12 kV SRMU have?
Short-time withstand current is 20 kA for 3 s, making capacity 52 kA. Impulse withstand voltage is 85 kV.
How is SRMU connected to SCADA?
The motorized version with the ETR304/306 relay transmits data over DNP 3.0, MODBUS and IEC 60870-5-101/104. The manual version works with the self-powered relay ETR20H.
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