Modular cabinet type air-insulated metal-enclosed MV cubicles that are produced according to standard of TS IEC 622271-200, the specifications of TEDASmyD/95-007.D, Power Installations Regulations and Earthing in Electrical Installations Regulations. Also, every type of material used in cubicles such as disconnectors, busbar, circuit breaker, counter, measurement equipment, relay, current and voltage transformers should be produced conforming to standards. This type of cubicles is suitable for use in the building. The degree of protection of cubicles is IP3x. The common electrical properties of main circuits of the modular metal-enclosed switchgears and MV kit and nominal rated values as below:
- Normal busbar rated current 630 A, 1250 A
- 1 s resistance rated current 16 kA
- Top resistance rated current 40 kA-top
Auxiliary supply voltage is DC 24V in Izmir and lots of sites. However, some areas it can be different for exle in Anatolia location of Istanbul it is DC 110V. Because of that, applications of local distribution companies should be considered during the project. In case of circuit breakers, motor voltage of spring loading is AC 220V in general. Disconnectors can be air-insulated or SF6 gas- insulated, but load break switches are SF6 gas-insulated. The disconnectors are 3-poles 2-positions (open, close) or 3-poles 3-positions (open, close, earthing) . Load break switches are manufactured as structure that does not require additional gas during two decades of life. They have to be provided gas discharge way to prevent injury to operating personnel in case of a dangerous level of gas pressure due to internal fault. The mechanical life of load break switches as voltage and no-load is 1000(one thousand) on -off. (M1 class). Also, they are manufactured to be able to cut the rated current(630 A) 100 times and make on-off 5 times on rated by-pass current (16 kA). As known, the load break switches cannot make on-off on by-pass condition. For this reason, circuit breakers are not used at feeders. The working mechanism of load break switches is the type of “controlled by the accumulated energy” . It can make closing using the energy accumulated on a spring which is founded by hand or motor. This process is provided with button/pin nearly, with closing coil energization remotely. In case of the necessary energy for opening process is obtained with founding opening spring automatically during closing process. The opening process can be made nearly or remotely like founding process. The disconnector, load break switches and earthing switches can be controlled separately and there is a mechanical lock against faulty maneuver between them. The earthing switches are type (B class) that can close 5 times on by-pass. The SF6 gas (hexane sulfur fluoride/ sulfur hexafluoride) is always used on the MV and HV electrical systems. The chemical structure of the SF6 gas is stable and normally in stationary phase and also, it is not toxic in pure form. It is colorless and odorless. Its dielectric strength is 89 kV/cm under the 1 bar pressure. Its dielectric strength feature is more than 3 times of air ones. It is heavier 5 times than air. Moreover, SF6 gas has high heat transfer specification. It is nonflammable but the phase of white and dust occurred because of by-pass is toxic and prejudicial for inhalation. Because of used extensively in industry it were included greenhouse gases in the Kyoto Protocol.
The Cubicle’s Types:
- Incoming/outgoing cubicles with load break switch
- Transformer protection cubicles (with fuse and load break swtich)
- Voltage transformer cubicles
- Outgoing cubicles with circuit breakers
- Busbar connection (coupling) cubicles
- Incoming/outgoing cubicles with disconnector
- Cable connection cubicles
- Voltage and current measurement cubicles
- Bus raising cubicles
10. Current measurement + bus rising cubicles
11. Current measurement cubicles
12. Busbar separator cubicles with circuit breaker (side outlet )
13. Busbar separator cubicles with load break switch (side outlet )
- Circuit breaker cubicle with voltage transformer
- Current voltage measurement cubicle with disconnector
- Parafudr cubicle
- Wall switch cubicle
- Current and voltage measurement cubicle (right side inlet)
- Current and voltage measurement cubicle (cable outlet)
- Bus connection (coupling) cubicle with load break switch (right side inlet)
- Motor feeding cubicle with vacuum contactor
- Condenser cubicle with vacuum contactor
