A generator speed measuring gear simulation instrument

Abstract

This utility model discloses a generator speed measuring gear disk simulator, which can simulate the rotation of the turbine generator gear disk in a waterless state during "fault simulation and control mode switching test". This avoids the speed governor misinterpreting the turbine generator gear disk as a "gear disk signal fault", thus preventing the speed governor control PLC from constantly switching operations. This improves the quality of turbine generator unit maintenance and allows for efficient completion of the speed governor's waterless linkage test. Specifically, it includes a PLC controller and a simulation mechanism for simulating the rotation of the turbine generator gear disk. The simulation mechanism includes a coaxially connected mechanical gear disk and a stepper motor. The operating state of the stepper motor is controlled by a pulse controller connected to the PLC controller. The PLC controller is connected to a human-machine interface screen and a frequency transformer, which is connected to a frequency transmitter.

Description

Technical Field

[0001] This utility model relates to the technical field of simulators, and in particular to a generator speed measuring gear simulator. Background Technology

[0002] In hydropower plants, turbine generator units need to undergo annual maintenance every year. According to GB9652.2 "Test of Hydropower Turbine Control System", the "Fault Simulation and Control Mode Switching Test" requires simulating the fault of the gear speed measurement signal to verify the correctness of the governor system's operation.

[0003] However, when the generator set is under maintenance, the speed measuring gear cannot actually rotate. In the waterless test of the governor, the instruments on the market can only send PT signals and lack gear signals, making it difficult to truly simulate the real state of the governor's power generation operation. During subsequent tests, the governor will be judged as having a "gear signal failure", causing the governor control PLC to switch operations continuously, which seriously affects the accuracy of the test results and the quality of maintenance. Utility Model Content

[0004] This invention provides a generator speed measuring gear simulator to solve the above-mentioned technical problems.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0006] A generator speed measuring gear simulation instrument includes a PLC controller and a simulation mechanism for simulating the rotation of a turbine generator gear. The simulation mechanism includes a mechanical gear and a stepper motor connected coaxially. The operating state of the stepper motor is controlled by a pulse controller, which is connected to the PLC controller. The PLC controller is connected to a human-machine interface screen and a frequency transformer, and the frequency transformer is connected to a frequency transmitter.

[0007] Preferably, the power supply module has a switching power supply that converts 220V AC voltage to 24V DC voltage and ±12V DC voltage. The 24V DC voltage of the switching power supply is connected to the PLC controller, the stepper motor and the human-machine interface screen, respectively, and the ±12V DC voltage is connected to the frequency transformer, the frequency transmitter and the pulse controller.

[0008] Compared with the prior art, the present invention has the following beneficial effects:

[0009] This invention can simulate the rotation of the turbine generator's gear disc in a waterless state. In the "fault simulation and control mode switching test", it can avoid the speed governor judging the turbine generator's gear disc as a "gear disc signal fault", which would cause the speed governor control PLC to continuously switch operation. This can improve the maintenance quality of the turbine generator set and efficiently complete the speed governor's waterless linkage test. Attached Figure Description

[0010] Figure 1 This is a signal control block diagram of this utility model;

[0011] Figure 2 This is the circuit block diagram of this utility model. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of this utility model are only used to explain this utility model and are not intended to limit this utility model.

[0013] This embodiment discloses a generator speed measuring gear disk simulator, which can simulate the rotation of the turbine generator gear disk in a waterless state during the "fault simulation and control mode switching test". This avoids the speed governor judging it as a "gear disk signal fault", which would cause the speed governor control PLC to continuously switch operation. This can improve the maintenance quality of the turbine generator set and efficiently complete the waterless linkage test of the speed governor.

[0014] like Figure 1 As shown, the aforementioned generator speed measuring gear simulator includes a PLC controller and a simulation mechanism for simulating the rotation of the turbine generator gear. The simulation mechanism includes a coaxially connected mechanical gear and a stepper motor. The operating state of the stepper motor is controlled by a pulse controller, which is connected to the PLC controller. The PLC controller is connected to a human-machine interface screen and a frequency transformer, which is connected to a frequency transmitter. Figure 2 As shown, the generator speed measuring gear simulator also includes a power supply module. The power supply module has a switching power supply that converts 220V AC voltage into 24V DC voltage and ±12V DC voltage. The 24V DC voltage of the switching power supply is connected to the PLC controller, the stepper motor and the human-machine interface screen, respectively, and the ±12V DC voltage is connected to the frequency transformer, the frequency transmitter and the pulse controller.

[0015] When the turbine generator's gear disc rotates in a simulated waterless state, the aforementioned PLC controller, acting as the central controller, primarily controls the pulse controller. The pulse controller outputs two-phase current to control the stepper motor, thereby indirectly controlling the gear disc's speed. The aforementioned frequency transmitter serves as a sampling quantity, capable of acquiring frequency cycles from 0 to 100V. For example, the frequency emitted by a professional speed controller simulation device is acquired by the frequency transmitter, then converted into low-voltage pulses by a frequency transformer, and finally converted into frequency cycles by a high-frequency pulse counter in the PLC, before being output to the pulse controller to adjust the gear disc's speed.

[0016] The rotational speed of the aforementioned geared disc can be set from the following three sources:

[0017] The first method involves external frequency measurement followed by conversion to output rotational speed.

[0018] The second method is to set it through the human-computer interface of the human-computer interaction screen;

[0019] The third method is to communicate via external communication such as MODBUS RTU or MODBUS TCP.

[0020] Specifically, the aforementioned PLC controller includes a PLC body sampling Siemens S7-1200 (1215C) and a communication module. The communication module has one RS485 interface, two network interfaces, 14 DI channels, and 10 DO channels, of which 4 DI channels are used as PWM for frequency output.

[0021] The aforementioned frequency transformer, connected to the frequency transmitter, forms a frequency measurement circuit. The output of the frequency measurement circuit is connected to the analog input terminal of the PLC. The frequency transmitter sends data to the high-frequency pulse counter in the PLC in the form of a 4-20mA analog signal. The PWM frequency output uses the PLC's own PWM function to cut ±12V into square waves with adjustable duty cycle and period for output, simulating the frequency of a sine wave. The output frequency follows the speed conversion ratio of the toothed disc. The stepper motor has a motor driver, which is powered by DC 24V provided by the power module. The pulse input terminal of the motor driver is connected to the DO channel of the PLC, and A+, A-, B+, and B- are connected to the stepper motor.

[0022] The aforementioned stepper motor drives the gear disk to rotate for simulated rotation. The mechanical gear disk has 8 teeth around its circumference. Next to the mechanical gear disk is a clamp for 3 speed measuring probes for fixing the probes.

[0023] The aforementioned human-machine interface (hereinafter referred to as HMI) communicates with the PLC via MODBUS TCP. Various data can be viewed and various setpoints can be set on the HMI, including output speed, module switching, etc.

[0024] The PLC controller's internal algorithms include a gear rotation speed algorithm and a frequency output algorithm. To reliably simulate the rotation of the generator's tachometer gear, certain parameters need to be set on the HMI, specifically the generator's rated speed and pole speed. For example, if the generator has 42 gear pairs and a rated speed of 71.42 r / min, the mechanical gear's speed is calculated as follows: f = 42 * 2 / 8 * 71.42 = 749.91 r / min. The frequency output pulse period is T = 1 / 50 = 0.02 seconds.

[0025] Of course, there may be other embodiments of this utility model. Without departing from the spirit and essence of this utility model, those skilled in the art can make various corresponding changes and modifications based on this utility model, but these corresponding changes and modifications should all fall within the protection scope of the appended claims of this utility model.

Claims

1. A generator tachometer disc simulator, characterized by, The device includes a PLC controller and a simulation mechanism for simulating the rotation of a turbine generator gear disk. The simulation mechanism includes a mechanical gear disk and a stepper motor connected coaxially. The operating state of the stepper motor is controlled by a pulse controller connected to the PLC controller. The PLC controller is connected to a human-machine interface screen and a frequency transformer. The frequency transformer is connected to a frequency transmitter.

2. The generator tachodisc simulator of claim 1 wherein, It also includes a power supply module, which has a switching power supply that converts 220V AC voltage into 24V DC voltage and ±12V DC voltage. The 24V DC voltage of the switching power supply is connected to the PLC controller, the stepper motor and the human-machine interface screen, respectively, and the ±12V DC voltage is connected to the frequency transformer, the frequency transmitter and the pulse controller.

Images