27kV switchgear

Why do you want to do 27kV when everyone else is doing 24kV? This is a good question. GE China R&D Center serves the world, developing switchgear that meets the requirements of various parts of the world. We have a platform such as IEC/GB/IEEE/CSA/GOST, and even if the investment is huge, we are willing to do it in one test. We have a long-term plan and a century old high-end product strategy to solve the world's most difficult problems.

27kV is the voltage level used in North America and other regions, as well as in South Korea (system voltage 25.8kV) and Canada (29.8kV), all of which are voltage sequence levels specified in the IEC62271-1 standard.

Unlike the 24kV defined in the IEC62271-1 standard, which has a power frequency withstand voltage of 50kV and a lightning impulse withstand voltage of 125kV, and the 24kV defined in the GB/T11022 standard, which has a power frequency withstand voltage of 50/65kV and a lightning impulse withstand voltage of 125kV, the 27kV defined in the IEEE/IEC standard has a power frequency withstand voltage of 60kV and a lightning impulse withstand voltage of 125kV.

Can the 24kV standard of GB be used for 27kV? It can only be said that the insulation voltage is satisfactory, but it does not mean that it can be applied, especially since the test parameters of the circuit breaker are still different.

Therefore, the transient recovery voltage TRV of the circuit breaker needs to refer to the 27kV voltage level requirements of IEC62271-100/IEEE C37.04 standard (after 2018, IEC and IEEE standards unified the TRV value for short-circuit breaking tests of circuit breakers, and the two standards are the same). The TRV T10 of the 27kV circuit breaker when breaking short-circuit current is 56.2kV, significantly higher than the 50kV of 24kV.

As early as 2013, GE China R&D Center successfully developed SecoVac-27 and SecoGear-27kV voltage level circuit breakers and switchgear, which were successfully used in Atlanta, North America, South America, and South Korea Braves Ballpark Project 、Proyecto Codelco Andina 、Sliding Center-2018 PC Olympic DAELIM  Waiting for the project.

The SecoVac-27 vacuum circuit breaker has passed all the basic breaking tests (according to the 27kV TRV value) and E2 level extended electrical life tests specified in IEC standards at KEMA. 50/60Hz， Both firmly grounded and non firmly grounded systems have a maximum rated current of 2500A.

SecoGear is based on the design of domestic 24kV mid mounted switchgear, with strengthened door panel design and increased number of hinges and locking hooks to withstand internal arc fault pressure. Design pressure relief channels to release internal arc fault pressure flames.

The width of the switch cabinet 1250/2000A is 800mm, the width of the 2500A cabinet is 1000mm, the depth of the cabinet is 1800mm, and the height of the cabinet is 2400mm.

The contact box and wall bushing are both of the internal and external pressure shielding type, with high insulation performance. Insulation, temperature rise, dynamic heating, breaking, etc. have all passed the KEMA 27kV voltage level type test.

In order to meet the seismic requirements of South American countries such as Chile, the switchgear also underwent seismic tests according to IBC (International Building Standard) with an acceleration of 2.42g. The disadvantage of a single handle quick opening door lock is poor vibration resistance. The relative movement between the switchgear door and the cabinet body is large, causing the locking pin to easily displace from the locking hook, resulting in the door panel opening. By locally adding bolt locks, the multi-point locking hook can withstand internal arc fault pressure and will not cause the door panel to open incorrectly due to earthquakes.

This switchgear is applied to 23/25.8/29.8kV voltage level systems in North America, South America, South Korea, etc. It is based on IEC standards and its parameters comply with IEEE standards.