A method and device for preventing accidental shutdown of a nuclear power reactor

Abstract

The embodiments of the invention disclose a method and a device for preventing accidental shutdown of a nuclear power reactor. In a nuclear power plant system, a generator is connected with a load switch, a transformer, a high-voltage switch and a power system in turn. The method comprises the following steps: judging whether there is an over-frequency event in the generator; if there is an over-frequency event in the generator, judging whether the load switch is closed; and if the load switch is closed, disconnecting the high-voltage switch finally. When there is an over-frequency event, the state of the load switch is considered, and mistaken tripping of the high-voltage switch is prevented. Therefore, the maintenance work goes smoothly, the unit comes back to normal quickly, and the safety of the unit is ensured.

Description

technical field [0001] The invention relates to the field of nuclear power, in particular to a method and device for preventing accidental shutdown of nuclear power reactors. Background technique [0002] In a nuclear power plant system, generators, load switches, transformers, high-voltage switches and power systems are usually connected in sequence. In order to prevent damage to the unit caused by overfrequency of the generator, it is usually necessary to detect the frequency of the generator outlet voltage in real time. When the frequency exceeds the frequency threshold, the duration of exceeding the frequency threshold is obtained. If the duration is greater than the duration threshold, the high voltage switch is disconnected. . [0003] When maintaining the generator, the staff disconnects the load switch. At this time, if the steam turbine in the turbo-generator set is overspeed, the frequency of the generator outlet voltage will exceed the frequency threshold, thereb...

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Problems solved by technology

[0003] When maintaining the generator, the staff disconnects the load switch. At this time, if the steam turbine in the turbo-generator set is overspeed, the frequency of the generator outlet voltage will exceed the frequency threshold, thereby disconnecting the high-voltage switch. The disconnection of the high-voltage switch on the main path for supplying power will lead to unexpected shutdown of the reactor, which will lead to major changes in the operation and working status of the entire plant equipment, forcing normal work to be affected and cannot be carried out normally. Other normal maintenance work can only be carried out after the auxiliary equipment is in a stable state; or when the load switch breaks down and disconnects, the generator suddenly loses all the load, due to the mechanical inertia of the turbo-generator set itself, and the resistance of the generator load disappears , causing the rotation speed of the turbo-generator unit to increase, and if the turbine overspeeds, the frequency of the generator outlet voltage will exceed the frequency threshold, thereby disconnecting the high-voltage switch, which will also cause the reactor to shut down unexpectedly, resulting in a breakdown of the operation and working status of the entire plant equipment. major changes

The transition of the reactor from the shutdown state to the normal operation state requires a large number of complicated operations and state transitions, so the trip of the high-voltage switch makes the unit return to the state slowly

At the same time, the high-voltage switch trips, the reactor loses the main external power supply, and the reactor shuts down, which will cause a great impact on the system and equipment, and may cause equipment damage, thereby affecting the safety of the unit.

[0004] Because the above-mentioned existing technology only disconnects the high-voltage switch according to the overfrequency event of the generator, the maintenance work is easily interrupted, the recovery state of the unit is slow, and the safety of the unit cannot be guaranteed

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