Vacuum Circuit Breaker

      

General Specification for 17,5 KV Vacuum Circuit Breaker

 

General

Performances

Construction – Functions

1. General

 

1.1 Medium Voltage Circuit Breakers (MVCB) shall be using vacuum switching technology, and shall comply with IEC 60694 and 62271-100 standards or with the corresponding standards applicable in the member countries.

1.2 Production site organisation shall be certified to comply with ISO 9002 and ISO 14001 standards and certificates shall be submitted together with the  product.

1.3 MVCB shall be designed according to Eco-design complying with ISO 14062. Especially MVCB’s materials shall be of halogen free type. They shall be supplied in recyclable packing complying with European Directives.
The manufacturer shall implement non polluting production processes that do not make use of chlorofluorocarbons, chlorinated hydrocarbons, ink for cardboard markings, etc

 

2. Performances

 

2.1 The general characteristics of the CB shall be in accordance with IEC standards :

2.1.1 IEC 60694 Edition 2-2 : Common specifications for high-voltage switchgear and control gear standards

2.1.2 IEC 62271-100 Edition 1.1  2003-05 : High-voltage alternating-current circuit-breakers

 

2.2 The MVCB shall have the following characteristics :

2.2.1 Rated voltage                                                               7,2-12-17,5 kV

2.2.2 Power frequency withstand voltage (50Hz-1mn)         50 kV   

2.2.3 Lightning impulse withstand voltage                           60-75-95 kV

2.2.4 Rated normal current                                                    (Ir to be given) A

2.2.5 Rated short-circuit breaking current                            (Isc to be given) kA

2.2.6 Rated Short time withstand current                              Isc (3sec)

2.2.7 Rated Short-circuit making current                              2.5 x Isc (at 50Hz) or 2.6 x Isc (at 60Hz)

 

2.3 Other characteristics :

2.3.1 Mechanical endurance                                                 Class M2 (10000 operations)

2.3.2 Electrical endurance                                                     Class E2

All the performances shall be certified by tests reports issued by a recognised international body such as ESEF, ASTA, ASEFA or Kema.

 

3. Construction – Functions

 

3.1 The MVCB shall be available in a fixed version and withdrawable version with a cradle as an option for interface in the cubicle.

 

3.2 MVCB shall be actuated by a spring operating mechanism with fast opening and closing, independant of the operator, and that can be operated without any auxiliary supply.

 

3.3 The operating mechanism shall be equipped with :

3.3.1 Opening and closing push-buttons

3.3.2 A mechanical “open-closed” position indicator

3.3.3 A mechanical “charged-discharged” closing spring indicator

3.3.4 A block of auxiliary contacts

 

3.4 The MVCB shall be fitted with a LV plug and socket for connection of the LV auxiliary circuit associated with the opening and closing of the circuit-breaker.

 

3.5 The following options shall be available, if required :

3.5.1 Remote control to enable opening and closing of the circuit-breaker. The auxiliary devices (releases and motors) shall accept auxiliary supply from 24V DC to 230V AC.

3.5.2 Mechanical operation counter.

3.5.3 Additional opening release (shunt or undervoltage type)

3.5.4 Low energy release as actuator for a self powered relay associated  to the CB.

 

3.6 The MVCB shall be fitted with the following safety devices:

3.6.1 Locking the circuit-breaker in the open position by the mean of a key.

3.6.2 For the withdrawable version:

- Interlocking between the LV plug connection and connected and disconnected positions, in order to prevent the closing of the CB unless the auxiliary circuits are connected, and to prevent disconnection of the auxiliary circuit with the CB closed in the service position.

- Full proof protection to avoid mismatch between cradle and circuit breaker

- Padlocking of the safety shutters to lock the shutters in closed position

- Anti-drop function in the cradle in order to prevent involuntary drop of the CB when extracting out of the cradle.

- Padlocking in the racked-out position.

- When applicable, interlocking between the cubicle door and the racking in/out of the CB : the racking in shall be possible only when the door is closed, and the opening of the door shall be possible only when the CB is racked out.

 

3.7 Indications

3.7.1 4 change over contacts shall be available to indicate Open closed position of the CB

3.7.2 For the withdrawable version:

- a mechanical position indicator for connected /disconnected position shall be located at the front of CB compartment door

- a block of 4 auxiliary contacts shall be available on the cradle to indicate the connected position of the CB

 

3.8 Earthing of the CB

As an option , it shall be possible to add a specific device in order to earth the CB during the racking in/out operation