Indoor gas insulated circuit-breakers

NegotiableUpdate on October 04

Model

Nature of the Manufacturer: Other

Product Category: Switchgear Components

Place of Origin: City, Province

Online Consult Contact Information

Overview

MH4 type Indoor SF6 circuit breaker manufactured by Rockwill in China. It uses sulphur hexafluoride gas (SF6) to extinguish the electric arc and as the insulating medium.

Product Details

MH4 type Indoor SF6 circuit breaker

-Summary-

ROCKWILL® Electric strives to bring our customers the latest technology and competitive pricing and best HM4 medium voltage circuit-breakers use sulphur hexafluoride gas (SF6) to extinguish the electric arc and as the insulating medium. Breaking in SF6 gas takes place without any arc chopping and without generation of overvoltages. These characteristics ensure long electrical life of the circuit-breaker and limited dynamic, dielectric and thermal stresses on the installation.

The circuit-breaker poles, which make up the breaking part, are systems with lifelong sealed pressure (IEC 62271- 100 and CEI 17-1 Stand- ards) and are maintenance-free.

The REH type mechanical operating mechanism, with stored energy has free release and allows opening and closing operations independently of the operator’s actions.

The operating mechanism and the poles are fixed to the metal structure which also acts as a support for the kinetics for operating the moving contacts. Circuit-breakers in the withdrawable version are fitted with a truck to allow racking in and racking out of the switchgear or enclosure.

The light and compact structure of the circuit-breaker ensures great sturdiness and excellent mechanical reliability.

Offering

Autopuffer breaking technique
Electric are extinction without chopped current
No restriking after breaking
Rapid recovery of the dielectric properties of the means of extinction
Withstａnd insulation voltage even at zero relative pressure(*)
Breaking up to 30% of the rated breaking capacity even at zero relative pressure(*)
Sealed for life poles
Test for checking gas tightness carried out three times on each piece of apparatus
Compact dimensions
Fixed and withdrawable version
Stored energy operating mechanism with anti-pumping device as standard common to the whole circuit-breaker series
Mechanical safety locks against incorrect operations
Simple personalisation thanks to a com-plete range of accessories
Maintenance-free
SF6 gas pressure control device (on request).

Fields of application

HM4 circuit-breakers are used in power distribution to control and protect lines, transformer and distribution substations, motors, transformers, capacitor banks, etc.
Thanks to the SF6 autopuffer breaking technique, the HM4 circuit-breakers do not generate operating overvoltages, and are therefore also highly suitable for retrofitting, upgrading and enlarging older installations where the motor,cable, etc. insulating materials may be particularly sensitive to dielectric stresses.

Breaking technique

The breaking technique of HD4 circuit-breakers is based on compression and self-blast techniques to obtain top performances at all service current values, with minimum arc times, gradual arc extinction without chopping, and no restriking or operating overvoltages.
The HM4 series brings to medium voltage the advantages of the “autopuffer" breaking technique already used in high voltage.

SF6 circuit-breaker		HM4-12	HM4-17	HM4-24	HM4-36	HM4-40
Standards		IEC 62271-100 CEI 17-1 (file 1375)
Rated voltage	Ur [kV]	12	17.5	24	36	40.5
Rated insulation voltage	Us [kV]	12	17.5	24	36	40.5
Withstａnd voltage at 50 Hz(1min)	Ud [kV]	28	38	50	70	95
Impulse withstａnd voltage	Up [kV]	75	95	125	170	185
Rated frequency	Fr [Hz]	50/60
Rated normal current (40 °C)	Ir [A]	630/800/1250/1600/2000/2500/3150/3600
Rated breaking capacity	Isc [kA]	12.5/16/25/31.5/40/50
Rated short-time	Ik [kA]	12.5/16/25/31.5/40/50
Making capacity	Ip [kA]	31.5/40/50/63/80/100/125
Operation sequence		O-0.3s-CO-15s-CO
Opening time	[ms]	45	45	45	45	45
Arcing time	[ms]	10~15	10~15	10~15	10~15	10~15
Total breaking time	[ms]	55~60	55~60	55~60	55~60	55~60
Closing time	[ms]	80	80	80	80	80
Maximum overall dimensions	H [mm]	640	649	818	730/1060	790/1123
	W[mm]	493	618	730	880/955	748/805
	D [mm]	496	496	620	695	833
Pole centre distance	I [mm]	150	210	275	350	275
Weight	[kg]	114	114	119	128	190
Absolute SF6 gas pressure	[kPa]	380	380	380	380	450
Operating temperature	[°C]	-5~+40
Tropicalization		IEC: 60068-2-30, 60721-2-1
Electromagnetic compatibility		IEC: 60694

Standards and approvals

HM4 circuit-breakers comply with IEC 62271-100, CEI 17-1 file 1375 Standards and with those of major industrialised countries.

They have undergone the following tests and guarantee safety and reliability of the apparatus in service in all installations.

Type tests: heating, withstａnd insulation at industrial and impulse frequency, short-time and peak withstａnd current, mechanical duration, making and breaking of short-circuit currents;

Individual tests: insulation with voltage at industrial frequency in the main circuits and insulation of the auxiliary and control circuits, measurement of the main circuit resistance, mechanical and electrical operation.

The HM4 circuit-breakers are tested according to the requirements of the IEC 62271-100 Standard (class E2 - table 21) and guarantee suitability for use in overhead lines, with rapid reclosing cycle.

Service safety

Thanks to the availability of a complete range of mechanical and electrical locks (on request), safe distribution switchgear can be constructed using HM4 circuit-breakers. The locking devices have been designed to prevent incorrect operations and to carry out inspection of the installation, ensuring maxi- mum operator safety