Gas generator switchgear

The TM2500 mobile power generation solution is a fast, mobile, and flexible power supply device provided by General Electric's GEV, providing on-demand power anytime, anywhere; The 22.8MW mobile gas turbine power generation system, also known as a mobile power station, does not fail to demonstrate its essence: it is actually more like a "containerized" GE CF6 jet engine, like a Boeing 747 equipped with four CF6 engines. When taking off, it has full power and can quickly reach maximum output power, quickly meeting the power demand of the grid; Of course, compared to the moment a jet plane lands, the TM2500 can also quickly power off.

The TM2500 mobile power generation system adopts a compact and modular design, which can be disassembled and easily transported by several trailers or a cargo plane. The system consists of four trailers, with the generator outlet switch cabinet, gas turbine, and generator installed on the same trailer. The switch cabinet is installed at the rear of the trailer, and the electricity generated by the generator is connected to the power user through the switch cabinet.

In order to meet the requirements of applications around the world, including North America, the switchgear is designed according to IEC/IEEE standards, with a rated voltage of 17.5kV (covering 15kV in North America), a rated current of 3150A, a short-circuit current of 50kA, and a rated frequency of 50/60Hz. The generator outlet circuit breaker has passed the type test of the generator outlet circuit breaker according to IEC/IEEE 62271-37-013 (a jointly published standard by IEC and IEEE) in KEMA, the Netherlands, and is suitable for 100MW generator applications. CT/VT/Grounding Transformer/Resistive Capacity Absorber/Surge Arrester all use American UL certified products. Outdoor switchgear with NEMA 3R design and high corrosion resistance standards.  

The TOC/MOC/ASD and grounding contacts, as well as other essential features of the American standard switchgear, are fully equipped and meet the requirements of IEEE C37.20.2 standard.

The generator circuit breaker cabinet adopts a mid mounted circuit breaker structure, with a resistance capacitance absorber and lightning arrester installed at the rear of the upper busbar room, and a voltage transformer handcart installed at the lower part; The voltage transformer in the auxiliary cabinet is of manual type, with a grounding switch at the rear. The lower part of the auxiliary cabinet is equipped with a grounding transformer and a grounding resistor, which are connected to the short-circuit point of the neutral point side cabinet of the generator through a high-voltage cable. The grounding switch of the auxiliary cabinet is interlocked with the mechanical key of the generator outlet circuit breaker to ensure that the grounding switch cannot be operated to close when the circuit breaker is closed. At the same time, a padlock mechanism is also designed to ensure that the circuit breaker cannot be shaken into the working position.

Due to the requirement to meet the IP44 outdoor use requirements, the busbar bridge is a completely sealed structure, and it is very difficult to achieve a temperature rise of 2500A. To reduce the impact of eddy currents, the busbar bridge is welded with stainless steel plates. For 50&60Hz applications, both circuit breakers and switchgear have passed the KEMA 50&60Hz test and are fully applicable. Due to the different voltages generated by the generator at 50Hz and 60Hz, the voltage transformer requires a structure with different voltage taps. The output voltage of the generator at 60Hz is 13.2kV, while at 50Hz it is 11kV. A conversion switch is used to ensure correct voltage output.

The design of the vehicle mounted system to reduce weight requires a relatively high weight. As the switchgear and generator set are on the same trailer, and the weight of the generator is very large, the weight of the switchgear system is required to be less than 3 tons. The width of the switchgear is reduced to 1.8 meters, and the voltage transformers are arranged in a cross shape to reduce the width of the trolley and lower the cabinet width of the auxiliary cabinet to 0.8 meters, resulting in a compact arrangement of components;

The integrated waterproof outdoor box adopts a switch cabinet panel and frame type, without the need for separate columns or bases, and is completely supported by the self standing structure of the switch cabinet body. The front and rear door panels are installed to fix the frame and connect to the cabinet body, and the top waterproof cover plate is also directly connected to the top of the switch cabinet; Reduce weight by 20%;

If four American standard through type low-voltage transformers are used for each phase, the size and weight are only 156kg. The weight is reduced by 35%. At the same time, a round copper busbar is used to solve the insulation problem of low-voltage current transformers. Due to the large current carrying capacity of the tubular busbar, the weight is also reduced by 10%;

The design of the switchgear system for environmental adaptability and transportation vibration requires installation on a trailer for transportation. The switchgear has passed the international building standard IBC seismic test 2.42g acceleration test, but is installed on a trailer and considered to be fixedly connected to the generator. A spring damping device is designed to reduce the damage of vibration to the switchgear during transportation.

Experimental verification

The TM2500 generator outlet switchgear system has undergone rigorous testing.

The 50kA switchgear has passed the switchgear type test of IEC62271-200, and the switchgear has also passed the international building standard IBC seismic test;

The temperature rise test is conducted on the entire circuit including the generator side cabinet, busbar bridge, and cable connection terminals. Due to the requirements 2500A@50OC Temperature, therefore the test current is 2500A 60Hz, and there is at least 10K margin for temperature rise

Insulation tests were conducted on the entire system, including a power frequency withstand voltage of 38kV for 1 minute and a lightning impulse voltage of 95kV;

NEMA 3R waterproof test was conducted on the switchgear, with a protection level equivalent to GB/T4208 IP44, including waterproof testing

Due to the global application of TM2500, the low-voltage junction box has passed CE testing and obtained CE certification;

The prototype was also sent to Hungary for overall debugging and testing, and successfully passed all tests.