Gas-steam combined cycle unit synchronous phasing test debugging method

Abstract

The invention provides a gas-steam combined cycle unit synchronous phasing test debugging method. Before first synchronous grid connection of a gas turbine generator, the gas turbine generator is usedto drive a gas turbine main transformer, a main transformer high-voltage side busbar and a steam turbine main transformer for stepping up from zero voltage; and then, synchronous loop check and phasing test are carried out on all synchronous points of the gas turbine generator and the steam turbine generator at one time. The debugging method has a simple operation process, synchronous loop checkand phasing test can be carried out on all synchronous points of the gas turbine generator and the steam turbine generator at one time, the debugging time is greatly shortened, the debugging efficiency is ensured, and the time of the start phase of the whole unit is controllable; the gas consumption of the gas turbine can be saved with many economic benefits; and voltage conduction check is carried out on primary devices such as the steam turbine main transformer and the secondary voltage loop before start of the whole steam turbine, problems can be found out effectively in advance and are timely solved, the potential risk of start debugging of the whole steam turbine later is reduced, and the safety is extremely high.

Description

technical field [0001] The invention relates to a debugging method for a gas-steam combined cycle unit with two main transformers starting from zero to boost the pressure and performing a phase-setting test at the same time, and belongs to the technical field of start-up debugging methods for a gas-steam combined cycle unit. Background technique [0002] In a power plant, it is a common operation for generators to be connected to the grid and put into operation. Asynchronous closing of generators or a large closing angle will cause torsional vibration problems in the shaft system of the generator set, and even cause serious damage to the rotor shafting system. Therefore, the rationality, correctness and reliability of the synchronous circuit of the generator is one of the first conditions to ensure that the generator set is put into operation safely, reliably, accurately and quickly. [0003] figure 1 It is the electrical main wiring diagram of the traditional gas-steam com...

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Problems solved by technology

[0006] The above-mentioned debugging method has the following deficiencies and defects: the duration is long, which increases the risk of debugging on the one hand, and increases the consumption of gas during the debugging on the other hand; The substation performs reverse power transmission impact closing, the operation mode is unsafe, and it will also cause a certain impact on the power grid

Therefore, in the prior art method, it is of little significance to inspect the operation of the system by reversely feeding the main transformer of the steam turbine.

[0009] 2. In the gas-steam combined cycle unit, the low-voltage side of the main transformer of the steam turbine generator is not connected to the factory transformer, so when the main transformer of the steam turbine is reversed, the polarity of its differential protection cannot be verified under load. Therefore, this Synchronous loop inspection and phasing test are carried out in the operation mode, and the system itself has certain insecurity

[0010] 3. The shock closing of the transformer reverse transmission will also cause a certain impact on the power grid

Because the transformer will generate a large amplitude excitation inrush current when it impacts on the switch, it may induce the adjacent operating transformer to generate "inrush current" and trip by mistake, causing a large-scale power outage; the excitation inrush current with a large value will cause the transformer and open circuit The transformer is damaged due to excessive electromotive force; the DC component in the excitation inrush current will cause the magnetic circuit of the current transformer to be over-magnetized, which will greatly reduce the measurement accuracy and the correct action rate of the relay protection device; a large number of harmonics in the excitation inrush current will also affect the current transformer. Serious pollution caused by grid power quality

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