HGTXGN□-12 type solid insulated fully-enclosed ring main unit(RMU) is a kind of fully-sealed power supply unit. All the living parts and switch are fully sealed in an epoxy resin shell without any gas, therefore the whole switch device is not affected by external environment, and this can ensure operation stability and personal safety and realize free of maintainance. This RMU has two types of indoor and outdoor. Sealing the indoor type of RMUs in a metal enclosure makes up the outdoor mutil loops ring networks power supply unit.The RMU is used in power distribution systems with rated voltage 12kV, three phases, AC 50/60Hz for ring network power supply or terminal power supply. The RMU is applicable to the power distribution systems for industrial & mining enterprises, residential communities, schools and gardens. It can also be equipped into a compact box type substation to control and protect the power distribution transformers. So both of the indoor and outdoor typies RMUs can realize power distribution antomation.
1. Altitude: ≤3000m;
2. Ambient temperature: outdoor, -60℃～+60℃；indoor, -10℃～+25℃；
3. Wind speed: ≤35m/s (wind pressure ≤700Pa);
4. Earthquake intensity: ≤grade 8;
5. Relative humidity: monthly average ≤90%; daily average ≤95%.
6. Ice thickness: ≤10mm
7. Sunlight intensity: ≤1000W/m2
8. Pollution degree: ≤Ⅳ(GB5582);
9. Applicable occasions: ambient air should not be obviously polluted by dust, water vapor, salt fog, corrosive gases or inflammable gas. But the outdoor type can be used in the harsh environmental conditions.


Rated parameters for RMU

No. Item Unit Data 1 Rated voltage kV 12 2 Rated current A 630、1000、1250 3 Rated frequency Hz 50/60 4 Rated short-time withstand current for isolator/granding switch(4s) kA 16、20、25 5 Rated peak withstand current for isolator/granding switch 40、50、63 6 Rated short-circuit breaking current 16、20、25 7 Breaking times of rated short-circuit breaking current times 30 8 Rated short-circuit making current(peak) kA 40、50、63 9 1min P.F withstand voltage Across contact distance, phase to phase, phase to earth kV 42 Across isolating distance 48 Lightning impulse withstand voltage Across contact distance, phase to phase, phase to earth 75 Across isolating distance 85 10 Mechanical life Vacuum circuit breaker times 10000 Isolating switch / grounding switch 2000 11 Resistance of main loop(one unit) ｕΩ ≤100 12 Breaking current for different phases grounding fault kA 17.4 13 Protection class of housing IP 3X

Mechanical property parameters for VCB

No. Item Unit Data 1 Rated operating sequence O-0.3s-CO-180s-CO 2 1min P.F withstand voltage for secondary loop kV 2 3 Distance between open contacts mm 9±1 4 Contact over-travel 3±0.5 5 Average opening speed m/s 1.2±0.2 6 Average closing speed 0.8±0.2 7 Contact close-bouncing time ms ≤2 8 Closing time 25～70 9 Opening time 20～50 10 Phase-to-phase spacing mm 135±1 11 Three-phase opening non-simultaneity ms ≤2 12 Three-phase closing non-simultaneity ≤2 13 Rated closing/opening operating voltage V DC220 14 Max/min closing operating voltage DC242/176 15 Max/min opening operating voltage DC264/143 16 Opening rebound mm ≤2

1. The high voltage load break switch and high voltage live parts are sealed in an epoxy resin insulated sleeve shell without any gas. The vacuum arc-extingushing chamber is small and with the function of reliable arc extinction. With grounding switch, the load break switch has three stations of closing, opening and grounding. The grounding knife also has the function of isolating knife.
2. The switchgear can accommodate 1 to 5-way load break switch units, or 1 to 5-way vacuum circuit breaker units. The outgoing lines for each unit are through three high voltage bushings which are convenient for cable connection.
3. The sealed box is made of imported materials. The joint of the operation mechanism and high voltage bushing adopt strict sealing measures to ensure the good performance.
4. The high voltage bushings and insulating cylinders are made of imported epoxy resin with APG technology. They are tightly fitted and connected by silicon rubber sleeve with good sealing performance.
5. Each way is equipped with an independent operation mechanism which is mounted on the front of the cabinet body with a variety of mechanical interlock functions.
6. Both of the load break switch and grounding switch are provided with spring operating mechanism, the load break switch can be for manual or electric operation, while the grounding switch is only for manmual operation.is not only for earthing, but also for isolating. The grounding switch is not only for earthing purpose, but also for isolating purpose.
7. The vacuum circuit breaker is provided with a permanent magnetic actuator which can be for electric closing and opening, or only for manual opening, not for manual closing. The vacuum circuit breaker can also be euipped with a spring operation mechanism which can be for manual operation and electric operation. It is provided with the distribution automation interface for future connection.
8. There is a visible window on the panel of RMU for observation of the opening or closing state of the isolating knife.
9. Each RMU has three separate and parallel insulated cylinders for convenient installation, easy replacement. Its biggest advantage is to avoid the white discharge between phases.