Comprehensive judgment method for tracking measurement value of excitation regulator during switching of main excitation and standby excitation
By introducing the terminal voltage criterion during the main and backup excitation switching, the problem of false alarm set value limitation caused by the unit working conditions in the prior art is solved, ensuring the normal start-up of the generator.
Patent Information
- Application Number
- CN202411243600.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-05
- Publication Date
- 2025-01-03
AI Technical Summary
The prior art does not consider the unit operating conditions during the main and backup excitation switching process, resulting in false alarms and a given value limit may occur during maintenance or shutdown, affecting the success rate of start-up.
On the basis of judging the status of the main and backup switches, a voltage criterion on the machine side is introduced, and the measured value is tracked only when the machine side voltage is ≥0.1Un to avoid falsely reporting the given value limit under low voltage conditions.
It effectively avoids the frequent set value limit and unsuccessful startup of the unit when the unit is shut down, and ensures the normal startup of the generator.
Smart Images
Figure CN119254060A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of excitation regulation, and in particular to a comprehensive judgment method for tracking measurement values of an excitation regulator during main-standby excitation switching. Background Art
[0002] At present, in power plants equipped with standby excitation, when the main excitation is modified or overhauled, the standby excitation voltage is generally used to boost the main excitation open-loop test first, and the main excitation is put into closed-loop test after confirming that the main excitation is operating normally. In the process of switching between the main and standby excitation, in order to prevent wrong strong excitation and ensure smooth switching, the main excitation set value will track the measured value. Specifically, the excitation regulator collects the position node signals of the main excitation switch and the standby excitation switch. When it is detected that the standby excitation switch is closed and the main excitation switch is open, the main excitation voltage set value will track the measured value, and the control angle is set to 90° to ensure that the main excitation has no output when the main excitation switch is put into use, and maintain the stable voltage at the machine end.
[0003] The existing technology only uses the main standby excitation switch position signal as the judgment criterion, which has the following problems: (1) The tracking measurement value and control angle are set to 90° mainly to ensure the smooth switching of the main and standby excitations during the operation of the generator, but the judgment criterion does not take into account the unit operating conditions. When the main standby excitation switch is simulated during the unit maintenance, the conditions that meet the main excitation separation and standby excitation connection will also appear, making the main excitation start tracking the measurement value logic. Since the measured value is 0, the given value is set to 0 and the given value range is limited to the minimum set value of 0.1 allowed. At the same time, the given value limit is reported, indicating that the given value has reached the minimum value and no longer responds to the demagnetization command. When the standby excitation is disconnected again, the given value limit will be restored. When the unit is shut down, starting the tracking measurement value logic is meaningless, and the given value limit caused will mislead the operation and maintenance personnel. (2) Both the main excitation and standby excitation are in the disconnected position. If the standby excitation node malfunctions, the excitation regulator detects that the standby excitation is turned on and the given value will track the measured value. Since the unit is in a shutdown state, the measured value is 0 and the given value tracks to the lower limit of 0.1. If the unit is started at this time, the given value is only 0.1, which will result in failure to start up normally to the rated value, affecting the success rate of the start-up. Summary of the invention
[0004] The present invention provides a comprehensive judgment method for tracking the measured value of an excitation regulator during main-standby excitation switching, which solves the problem in the prior art that static disconnection of the main-standby excitation switch or malfunction of the standby excitation node causes a given value limitation, thereby causing the generator to fail to start.
[0005] In order to realize the above technical features, the object of the present invention is realized as follows: a comprehensive judgment method for tracking the measured value of the excitation regulator during the main-standby excitation switching, based on judging whether the main excitation switch is in the open state and whether the standby excitation switch is in the closed state, and judging the machine-end voltage at the same time, when the machine-end voltage is ≥0.1Un, the measured value is tracked; Among them, Un is the rated value of the terminal voltage.
[0006] Preferably, when the main and standby excitation switches are operated during unit maintenance, when the main excitation switch is opened and the standby excitation switch is closed, but the terminal voltage is lower than 0.1Un at this time, the tracking measurement value start condition is not met, and the excitation regulator set value does not respond, thereby preventing false alarm of the set value limit.
[0007] Preferably, when the unit is shut down and the main excitation switch and the standby excitation switch are both opened, if the standby excitation switch position node malfunctions, but the machine-end voltage is lower than 0.1Un at this time, the tracking measurement value start condition is not met, and the excitation regulator set value does not respond, thereby not causing a false alarm of the set value limit.
[0008] Preferably, since the given value tracking measurement value will not be triggered when the machine is shut down, the given value remains 100%, and there will be no abnormal startup caused by the given value being only 0.1 when the machine is started.
[0009] Beneficial effects of the present invention: 1. Compared with the prior art, the present invention can solve the frequent set value limitation caused by the operation of the main standby excitation switch when the unit is shut down, and can also avoid the failure of starting up due to the set value limitation. BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.
[0011] Figure 1 The existing set value tracking measurement value judgment logic during main-standby excitation switching.
[0012] Figure 2 This is the improved set value tracking measurement value judgment logic during main-standby excitation switching of the present invention. DETAILED DESCRIPTION
[0013] The embodiments of the present invention are further described below in conjunction with the accompanying drawings.
[0014] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.
[0015] Embodiment 1: Because there is no problem with the existing technology when the unit is operating normally. Only when the unit is shut down will the displacement or malfunction of the main standby excitation switch node cause the given value to be limited or the startup to fail. Therefore, it is only necessary to introduce a unit operating condition into the judgment logic of the existing tracking measurement value, which can be specifically simplified to the machine-end voltage measurement value ≥ 10% of the rated value.
[0016] To achieve the above object, the present invention introduces a machine-end voltage criterion and proposes a comprehensive judgment method for tracking the measured value of the excitation regulator during the main-standby excitation switching.
[0017] Specifically, it is a comprehensive judgment method for tracking the measured value of the excitation regulator during the switching between main and standby excitation. First, it is judged whether the main excitation switch is in the open state, and then it is judged whether the standby excitation switch is in the closed state, and at the same time, the machine-end voltage is judged. When the machine-end voltage is ≥0.1Un, the measured value is tracked; wherein Un is the rated value of the machine-end voltage.
[0018] like Figure 2 As shown in the improved logic diagram, Figure 1 On this basis, the judgment condition of machine-end voltage ≥ 0.1Un is introduced. In this way, when the unit is shut down, since the new condition is not met, the given value will not track the measured value due to the operation of the main standby excitation switch or the node malfunction, thereby causing other impacts.
[0019] Specifically, when the main and standby excitation switches are operated during unit maintenance, the main excitation switch is opened and the standby excitation switch is closed, but the terminal voltage is basically 0 at this time, which is lower than 0.1Un and does not meet the start conditions for tracking the measured value. The excitation regulator set value does not respond, which will not cause a false alarm of the set value limit.
[0020] In addition, since the given value tracking measurement value will not be triggered during shutdown, the given value will still be 100%. In this way, even if the standby excitation position node malfunctions, there will be no abnormal startup due to the given value being only 0.1 at startup.
Claims
1. A comprehensive judgment method for tracking measurement values of an excitation regulator during main-standby excitation switching, characterized in that: On the basis of judging whether the main excitation switch is in the open state and whether the standby excitation switch is in the closed state, the machine terminal voltage is judged at the same time. When the machine terminal voltage is ≥0.1Un, the measured value is tracked; Among them, Un is the rated value of the terminal voltage.
2. According to claim 1, a comprehensive judgment method for tracking measurement values of an excitation regulator during main-standby excitation switching is characterized in that: When the main and standby excitation switches are operated during unit maintenance, when the main excitation switch is opened and the standby excitation switch is closed, but the terminal voltage is lower than 0.1Un at this time, the start condition of tracking the measured value is not met, and the excitation regulator set value does not respond, which will not cause a false alarm of the set value limit.
3. The comprehensive judgment method of the excitation regulator tracking measurement value during the main-standby excitation switching according to claim 1 is characterized in that: When the unit is shut down and the main excitation switch and the standby excitation switch are both opened, if the standby excitation switch position node malfunctions, but the machine terminal voltage is lower than 0.1Un at this time, the tracking measurement value start condition is not met, and the excitation regulator set value does not respond, which will not cause a false alarm of the set value limit.
4. A comprehensive judgment method for tracking measurement values of an excitation regulator during main-standby excitation switching according to claims 2 and 3, characterized in that: Since the given value will not be triggered to track the measured value when the machine is shut down, the given value will still be 100%, so there will be no abnormal startup caused by the given value being only 0.1 when the machine is started.