A gear selection test device for generator neutral point arc suppression coil

Abstract

A gear selection test device for a neutral arc suppression coil of a generator includes a first voltage sensing unit connected to the neutral arc suppression coil, and a first voltage sensing unit for detecting the current of a neutral grounding line, a second voltage sensing unit for detecting the generator terminal voltage through a terminal voltage transformer, a second current sensing unit for detecting the terminal single-phase grounding current signal, and a gear knob is provided on the first voltage sensing unit, the second voltage sensing unit, the first current sensing unit, and the second current sensing unit. The neutral point voltage, the generator terminal line voltage, the neutral point current, and the terminal single-phase grounding current signal can be monitored simultaneously; the voltage and current signal waveforms can be displayed and stored in real time, and harmonic analysis can be performed on the waveforms; the test wiring is convenient, which can greatly improve the work efficiency and ensure the safety of on-site operations.

Description

Technical Field

[0001] The invention relates to the technical field of water turbine generator safety, and in particular to a gear selection test device for a neutral point arc suppression coil of a generator. Background Art

[0002] The stator grounding fault of a hydro-turbine generator is the most common generator fault. When a grounding fault occurs in a large generator set, a large capacitive current to the ground will be generated. In order to limit the grounding fault current within the allowable range, the neutral point is often operated by arc suppression coil grounding. When a single-phase grounding fault occurs in the generator stator, if it cannot be promptly checked, the fault current will endanger the stator core and even develop into a more harmful inter-phase and inter-turn short-circuit fault. When a single-phase grounding fault occurs, a large capacitive current to the ground will appear. It is necessary to use a suitable arc suppression coil connected between the busbar and the ground to compensate the capacitive current to the minimum. The purpose of testing the single-phase grounding fault current of the generator stator is to verify whether the arc suppression coil can effectively compensate for the fault current when a single-phase grounding occurs in the generator, to ensure that the grounding arc is extinguished instantly, to eliminate the intermittent grounding overvoltage of the arc light, and to prevent the accident from further expanding into an inter-turn or inter-phase short circuit.

[0003] At present, the on-site test requires the cooperation of multiple instruments to complete the test. There is no device dedicated to the generator arc suppression coil selection test. The existing technology has the following defects and shortcomings:

[0004] (1) There is no dedicated test equipment. On-site tests require artificial construction of the test platform. Various test equipment must be prepared in the early stage, and the process is cumbersome;

[0005] (2) The test platform is directly connected to high-voltage equipment such as the neutral point of the generator. The high voltage of the equipment during the test poses a risk to personnel and equipment.

[0006] (3) The test site requires many instruments and the wiring is complicated. The equipment needs to be wired on site. Wrong or missed connections will lead to test failure or even equipment loss.

[0007] (4) The test records rely on manual reading and data analysis, which results in large reading errors and data analysis errors, which is not conducive to test data analysis and judgment. Summary of the invention

[0008] The technical problem to be solved by the present invention is to provide a generator neutral point arc suppression coil gear selection test device, which has an arc suppression coil gear selection test function and can simultaneously monitor the neutral point voltage, generator machine end line voltage, neutral point current, and machine end single-phase grounding current signal; it can display and store voltage and current signal waveforms in real time and perform harmonic analysis on the waveforms; the test wiring is convenient, which can greatly improve work efficiency and ensure on-site operation safety.

[0009] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0010] A generator neutral point arc suppression coil gear selection test device comprises a first voltage sensing unit connected to the neutral point arc suppression coil, and a first current sensing unit for detecting the neutral point grounding line current, a second voltage sensing unit for detecting the generator end voltage through a machine end voltage transformer, and a second current sensing unit for detecting the machine end single-phase grounding current signal, the first voltage sensing unit, the second voltage sensing unit, the first current sensing unit and the second current sensing unit all communicate data with the arc suppression coil gear selection test device through wired or / and wireless communication, and the first voltage sensing unit, the second voltage sensing unit, the first current sensing unit and the second current sensing unit are provided with gear knobs.

[0011] The above-mentioned first current sensing unit and second current sensing unit are provided with a sensing unit display screen for displaying the monitored current value, and respectively perform limited and wireless communication with the arc extinguishing coil gear selection test device through the current sensing unit wired connection port and the sensing unit antenna, select the communication mode through the communication mode selection button, and select the current monitoring gear through the current sensing unit unit gear knob.

[0012] The above-mentioned first voltage sensing unit and second voltage sensing unit are provided with a sensing unit display screen for displaying the monitored voltage value, and respectively perform limited and wireless communication with the arc extinguishing coil gear selection test device through the voltage sensing unit wired connection port and the sensing unit antenna, select the communication mode through the communication mode selection button, and select the voltage monitoring gear through the voltage sensing unit unit gear knob.

[0013] The above-mentioned arc suppression coil selection test device is provided with a human-computer interaction screen for displaying the detected single-phase grounding terminal voltage and current values ​​and the arc suppression coil terminal voltage and current values, as well as a wired current connection port and a wired voltage connection port for connecting to the wired connection port of the current sensing unit and the wired connection port of the voltage sensing unit respectively, and an antenna for wireless communication with the sensing unit antenna.

[0014] The neutral point arc suppression coil grounding terminal is provided with a neutral point knife switch, and the neutral point knife switch is opened and closed under the control of the arc suppression coil gear selection test device.

[0015] The invention provides a generator neutral point arc suppression coil gear selection test device, which has the following beneficial effects:

[0016] (1) The test equipment is modularized, and the modules can communicate with each other wirelessly or wiredly;

[0017] (2) The voltage sensing unit, current sensing unit, and arc suppression coil selection test device all collect primary signals through Rogowski coils or voltage transformers, and the test wiring is simple, safe, and reliable;

[0018] (3) The arc suppression coil selection test device can collect the neutral point current, the single-phase grounding current at the generator end, the neutral point voltage, and the generator end line voltage signals, and perform analysis and calculation, which is convenient for data analysis and on-site operation;

[0019] (4) Harmonic analysis can be performed on the waveform to facilitate on-site analysis and elimination of harmonic interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0021] Figure 1 It is the principle diagram of the test device of the present invention;

[0022] Figure 2 This is a schematic diagram of the arc suppression coil selection test device;

[0023] Figure 3 is a schematic diagram of a current sensing unit;

[0024] Figure 4 Schematic diagram of a voltage sensing unit.

[0025] Among them: neutral point knife switch 1, neutral point arc suppression coil 2, arc suppression coil gear selection test device 3, human-computer interaction screen 31, wired current connection port 32, wired voltage connection port 33, antenna 34, first voltage sensing unit 4, second voltage sensing unit 5, machine-end voltage transformer 6, first current sensing unit 7, second current sensing unit 8, Rogowski coil 9, sensing unit display screen 10, communication mode selection button 11, current sensing unit wired connection port 12, sensing unit antenna 13, current sensing unit unit gear knob 14, voltage sensing unit wired connection port 15, voltage sensing unit unit gear knob 16. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings and embodiments.

[0027] like Figure 1-4 As shown in the figure, a generator neutral point arc suppression coil gear selection test device includes a first voltage sensing unit 4 connected to the neutral point arc suppression coil 2, and a first current sensing unit 7 for detecting the neutral point grounding line current, the second voltage sensing unit 5 detects the generator end voltage through the machine end voltage transformer 6, and the second current sensing unit 8 detects the machine end single-phase grounding current signal, the first voltage sensing unit 4, the second voltage sensing unit 5, the first current sensing unit 7 and the second current sensing unit 8 all communicate data with the arc suppression coil gear selection test device 3 through wired or / and wireless communication, and the first voltage sensing unit 4, the second voltage sensing unit 5, the first current sensing unit 7 and the second current sensing unit 8 are provided with gear knobs.

[0028] The above-mentioned first current sensing unit 7 and second current sensing unit 8 are provided with a sensing unit display screen 10 for displaying the monitored current value, and respectively perform limited and wireless communication with the arc extinguishing coil gear selection test device 3 through the current sensing unit wired connection port 12 and the sensing unit antenna 13, select the communication mode through the communication mode selection button 11, and select the current monitoring gear through the current sensing unit unit gear knob 14.

[0029] The above-mentioned first voltage sensing unit 4 and second voltage sensing unit 5 are provided with a sensing unit display screen 10 for displaying the monitored voltage value, and respectively perform limited and wireless communication with the arc extinguishing coil gear selection test device 3 through the voltage sensing unit wired connection port 15 and the sensing unit antenna 13, select the communication mode through the communication mode selection button 11, and select the voltage monitoring gear through the voltage sensing unit unit gear knob 16.

[0030] The above-mentioned arc suppression coil gear selection test device 3 is provided with a human-machine interaction screen 31 for displaying the detected single-phase grounding terminal voltage and current values ​​and the arc suppression coil terminal voltage and current values, as well as a wired current connection port 32 and a wired voltage connection port 33 for connecting to the current sensing unit wired connection port 12 and the voltage sensing unit wired connection port 15 respectively, and an antenna 34 for wireless communication with the sensing unit antenna 13.

[0031] A neutral point switch 1 is provided at the grounding end of the neutral point arc extinguishing coil 2, and the neutral point switch 1 is opened and closed under the control of the arc extinguishing coil gear selection test device 3.

[0032] The first voltage sensing unit 4, the second voltage sensing unit 5, the first current sensing unit 7 and the second current sensing unit 8 are provided with a sensing data processor, and are connected to the sensing unit display screen 10 for displaying the monitored current value and voltage value. The data can be connected to the arc extinguishing coil selection test device 3 by wire or wireless means. The arc extinguishing coil selection test device 3 is provided with a computing control chip for summarizing, calculating and displaying the transmitted data. The arc extinguishing coil selection test device 3 is placed at the comprehensive calculation and summary personnel of the test to facilitate the summary and calculation of the overall results of the test. The arc extinguishing coil selection test device 3 can control the test process by controlling the opening and closing of the neutral point knife switch 1.

[0033] Example:

[0034] The schematic diagram of this test device is as follows: Figure 1 As shown:

[0035] The device is mainly composed of the following parts: 1 voltage sensing unit; 2 current sensing unit; 3 arc suppression coil test device;

[0036] (1 Voltage sensing unit: monitors the neutral point voltage and generator terminal line voltage signals, and transmits the data to the arc suppression coil selection test device through an antenna or coaxial cable;

[0037] (2 Current sensing unit: monitors the neutral point current and the single-phase grounding current signal at the machine end, and transmits the data to the arc suppression coil selection test device through an antenna or coaxial cable;

[0038] (3 Arc suppression coil selection test device: real-time display of current and voltage signals, storage of voltage and current signal waveforms, and harmonic analysis of the waveforms.

[0039] like Figure 2 As shown in the figure, it is a schematic diagram of the arc suppression coil selection test device, which includes the following:

[0040] (1 Touch screen: select and adjust functions through the touch screen, and display and analyze current and voltage signals in real time;

[0041] (2 Current 1 channel, current 2 channel: connect neutral point current and machine-end single-phase grounding current signals through wired communication;

[0042] (3 Voltage 1 channel, voltage 2 channel: connect the neutral point voltage and generator terminal line voltage signals through wired communication;

[0043] (4 Antenna: connect neutral point current, generator end single-phase grounding current, neutral point voltage, generator end line voltage signal through wireless communication;

[0044] like Figure 3 and 4 As shown in the figure, it is a schematic diagram of the voltage sensing unit and the current sensing unit, which includes the following:

[0045] (1 Display screen: displays the waveform of the current and voltage signals currently being measured, and displays the currently selected function and gear position;

[0046] (2 Communication mode: switch between wireless / wired communication mode;

[0047] (3 switches: turn on / off the instrument;

[0048] (4 Rogowski coil: measure current signal;

[0049] (5 Voltage signal: voltage input terminal;

[0050] (6 Wired communication: connect the neutral point current, machine end single-phase grounding current, neutral point voltage, generator end line voltage signals through wired communication.

[0051] The steps to use the device are as follows:

[0052] (1 According to Figure 1 Connect the voltage sensing unit, current sensing unit, arc suppression coil gear selection test device, and select the appropriate communication mode and gear;

[0053] (2 When the neutral point grounding switch is open, measure the single-phase grounding current at the machine end and the line voltage signal at the generator end. The instrument automatically calculates the fundamental wave and harmonic value of the single-phase grounding current under rated working conditions based on the current and voltage signals;

[0054] (3 Select the appropriate arc suppression coil position according to the single-phase grounding current value;

[0055] (4 When the neutral point grounding knife switch is closed, the neutral point current, the single-phase grounding current at the machine end, the neutral point voltage, and the generator end line voltage signal are measured. The instrument automatically calculates the single-phase grounding current fundamental wave and harmonic value under rated working conditions based on the current and voltage signals.

Claims

1. A generator neutral point arc suppression coil gear selection test device, characterized by: The invention comprises a first voltage sensing unit (4) connected to a neutral point arc extinguishing coil (2), and a first current sensing unit (7) for detecting a current of a neutral point grounding line, a second voltage sensing unit (5) for detecting a generator terminal voltage through a terminal voltage transformer (6), and a second current sensing unit (8) for detecting a single-phase grounding current signal at the terminal. The first voltage sensing unit (4), the second voltage sensing unit (5), the first current sensing unit (7) and the second current sensing unit (8) all communicate data with an arc extinguishing coil gear selection test device (3) through wired or / and wireless communication, and the first voltage sensing unit (4), the second voltage sensing unit (5), the first current sensing unit (7) and the second current sensing unit (8) are provided with gear knobs; A neutral point knife switch (1) is provided at the grounding end of the neutral point arc extinguishing coil (2), and the neutral point knife switch (1) is opened and closed under the control of the arc extinguishing coil gear selection test device (3); The steps to use the device are as follows: (1) Connect the voltage sensing unit, current sensing unit, arc suppression coil gear selection test device, and select the appropriate communication method and gear; (2) When the neutral point grounding switch is open, measure the single-phase grounding current at the machine end and the line voltage signal at the generator end. The instrument automatically calculates the fundamental wave and harmonic values ​​of the single-phase grounding current under rated conditions based on the current and voltage signals; (3) Select the appropriate arc suppression coil position according to the single-phase grounding current value; (4) When the neutral point grounding switch is closed, the neutral point current, the single-phase grounding current at the machine end, the neutral point voltage, and the generator end line voltage signal are measured. The instrument automatically calculates the fundamental wave and harmonic values ​​of the single-phase grounding current under rated conditions based on the current and voltage signals.

2. A generator neutral point arc suppression coil gear selection test device according to claim 1, characterized in that: The first current sensing unit (7) and the second current sensing unit (8) are provided with a sensing unit display screen (10) for displaying the monitored current value, and respectively perform limited and wireless communication with the arc extinguishing coil gear selection test device (3) via a current sensing unit wired connection port (12) and a sensing unit antenna (13), select a communication mode via a communication mode selection button (11), and select a current monitoring gear via a current sensing unit unit gear knob (14).

3. A generator neutral point arc suppression coil gear selection test device according to claim 2, characterized in that: The first voltage sensing unit (4) and the second voltage sensing unit (5) are provided with a sensing unit display screen (10) for displaying the monitored voltage value, and respectively perform limited and wireless communication with the arc extinguishing coil gear selection test device (3) via a voltage sensing unit wired connection port (15) and a sensing unit antenna (13), select a communication mode via a communication mode selection button (11), and select a voltage monitoring gear via a voltage sensing unit unit gear knob (16).

4. A generator neutral point arc suppression coil gear selection test device according to claim 3, characterized in that: The arc suppression coil gear selection test device (3) is provided with a human-machine interactive screen (31) for displaying the detected single-phase grounding terminal voltage and current values ​​and arc suppression coil terminal voltage and current values, as well as a wired current connection port (32) and a wired voltage connection port (33) for connecting to the current sensing unit wired connection port (12) and the voltage sensing unit wired connection port (15) respectively, and an antenna (34) for wireless communication with the sensing unit antenna (13).

Images