Quick-speed synchronization parallelly-arranged system between electric networks and method of use thereof

Abstract

The invention provides a quick corresponding parallel system between electric networks and a relative application method, which relates to a rectifying-investing system formed by high voltage electric power electric appliances, and can quickly connect two electric networks with different frequencies, quickly realize load support from the circle electric network to the low circle electric network, and eliminate the system vibration to prevent accident expansion. Following the load transmission, after satisfying the conditions of corresponding parallel, the two networks automatically complete the corresponding parallel, and exit the quick parallel system; besides, the same method also can quickly achieve ring network parallel operation for the line. Being safe and reliable, the invention has advantages of quick parallel speed and high automatization level, thereby radically solving the situation of manual operation in the prior electric network parallel; moreover, the parallel system is further applicable to the test of rising current and rising voltage for the line.

Description

Technical field [0001] The invention relates to a synchronous parallel and ring network parallel system between power grids, in particular to a high-voltage power electronic device (SCR, gate turn-off thyristor GTO, insulated gate bipolar transistor IGBT, integrated gate commutation Thyristor IGCT) composed of rectification - inverter system. Background technique [0002] At present, large-scale hub substations play a very important role in connecting inter-provincial power grids, regional power grids and international power grids. The rapidity and safety of the parallel operation in the hub substation is related to whether the system can quickly restore the system in the event of an accident, and whether it can provide active support to the low-cycle power grid in time to eliminate system oscillation, prevent the expansion of the accident, and ensure the user’s Continuous power supply or fast restoration of power supply. However, there are the following problems in the sy...

AI Technical Summary

Problems solved by technology

[0012] Sometimes, in order to restore the connection of the system as soon as possible and eliminate the fault state, it is necessary to force the manual quasi-synchronous paralleling when the frequency difference and voltage difference are large, and the speed when the slip crosses the zero point is fast. A large system impact, in serious cases, will cause the relay protection device to act on tripping, causing the parallel failure and expanding the accident

[0013] Second, during the parallel operation of the long line ring network, although the pressure difference on both sides of the parallel point is small and the frequency difference is zero, due to the influence of the power flow, there will be a large phase angle difference

[0015] 1. The parallel speed is slow in the same period

Especially in the event of an accident, it is extremely unfavorable to quickly eliminate system oscillation, prevent the expansion of the accident, quickly restore the normal operation of the power grid, and ensure the safe operation of the system if it cannot quickly provide rapid active support to the low-cycle power grid.

In severe cases, part of the load of the low-cycle power grid should be cut off, resulting in power cuts

[0016] 2. Poor safety and reliability of parallel operation in the same period

There are many operating links, and it is easy to cause misoperation

Parallel operation in emergency situations is carried out under the condition of large voltage difference, large frequency difference, and fast slip, which is prone to large impacts, and in serious cases may also cause tripping of the protection device to cause parallel failure and expand the accident.

[0017] 3. Low level of automation

However, the parallel operation in the same period is carried out manually without automation, and its automation level lags behind the overall technical status, which has become a short board in the technical management of the entire power grid, and is not suitable for the situation requirements of the continuously expanding large power grid.

[0018] 4. When the phase angle difference of the ring network operation is too large, there are many risks in the work of adjusting the power flow distribution of the system, some equipment may approach the stability limit, and sometimes the system stability will be damaged, and the load-side power rationing will interrupt the power supply of some users

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