CN212989624U - Self-checking circuit suitable for direct current injection type rotor ground protection measurement loop - Google Patents
Self-checking circuit suitable for direct current injection type rotor ground protection measurement loop Download PDFInfo
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- CN212989624U CN212989624U CN202021493661.XU CN202021493661U CN212989624U CN 212989624 U CN212989624 U CN 212989624U CN 202021493661 U CN202021493661 U CN 202021493661U CN 212989624 U CN212989624 U CN 212989624U
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Abstract
The utility model discloses a self-checking circuit suitable for direct current injection formula rotor ground protection measurement circuit, direct current injection formula rotor ground protection measurement circuit include concatenate injection direct current source E between rotor macroaxis and rotor negative pole, two at least resistance R1 and R2, connect in parallel controllable switch and diode D1 on one of them resistance both ends; the self-checking circuit comprises a relay K1, and a relay K1 comprises a normally closed contact and a normally open contact; a first end of a normally closed contact of K1 is connected with the negative electrode of the rotor, and a second end of the normally closed contact is connected with the injection direct current source, the diode and the at least two resistors in the measuring loop in series and then connected with the large shaft of the rotor; the first end of a normally open contact of the K1 is connected with the rotor large shaft, and the second end of the normally open contact of the K1 is connected with the second end of the normally closed contact of the K3578; the coil of K1 is connected in a self-test control loop. Utilize the utility model discloses can carry out the self-checking to measuring circuit, protect when avoiding because of the trouble that measuring circuit trouble leads to and refuse to move.
Description
Technical Field
The utility model relates to a generator operation monitoring and protection technical field, especially a strong protection circuit that stimulates suitable for direct current injection type rotor ground protection measures return circuit.
Background
The rotor winding of the generator is used as an important component of the generator, provides a rotating rotor magnetic field for the generator, cuts the stator winding and generates electricity. The common fault modes of insulation damage of the rotor winding include one-point grounding of the rotor winding and two-point grounding of the rotor winding, the one-point grounding of the rotor winding does not cause damage to the generator, but if the second-point grounding occurs successively, the vibration of the generator is caused, and the shafting and the turbine can be magnetized seriously, so that the injection type or ping-pong type rotor grounding protection is required to be configured to protect the one-point grounding fault of the rotor.
The current commonly used direct current injection type rotor ground protection measuring loop is shown in figure 1, a direct current injection power supply is self-generated and is superposed between a rotor cathode and a rotor large shaft through two resistors connected in series, one resistor is connected with an electronic switch in parallel, the electronic switch is switched on and switched off at a fixed frequency to change circuit parameters, and the rotor ground resistance is further calculated by measuring rotor leakage current of the electronic switch under two working conditions.
However, when the rotor has no ground fault, the measurement loop has no path, and the leakage current of the rotor is always zero, so that the self-check of the measurement loop cannot be performed, whether the measurement loop has a fault or not cannot be accurately obtained in time, and the protection is easily rejected when the rotor has a ground fault.
In addition, there are some problems with the protection method, such as when the rotor is excited by force and the positive electrode is grounded by metal, a large current flows through the measurement loop, which easily causes the damage of the components of the measurement loop, but if the circuit parameters are designed according to the maximum excitation voltage, the measurement accuracy of the resistance is insufficient.
Disclosure of Invention
The utility model aims at providing a self-checking circuit suitable for direct current injection type rotor ground protection measurement circuit can carry out the self-checking to measurement circuit, and the protection is refused to move when avoiding because of the trouble that measurement circuit trouble leads to.
The utility model adopts the technical proposal that: a self-checking circuit suitable for direct current injection type rotor ground protection measuring circuit comprises an injection direct current source E, at least two resistors R1 and R2, a controllable switch and a diode D1, wherein the injection direct current source E is connected between a rotor large shaft and a rotor negative electrode in series, and the controllable switch and the diode D1 are connected to two ends of one resistor in parallel;
the self-checking circuit comprises a relay K1, and a relay K1 comprises a normally closed contact and a normally open contact; a first end of a normally closed contact of K1 is connected with the negative electrode of the rotor, and a second end of the normally closed contact is connected with the injection direct current source, the diode and the at least two resistors in the measuring loop in series and then connected with the large shaft of the rotor; the first end of a normally open contact of the K1 is connected with the rotor large shaft, and the second end of the normally open contact of the K1 is connected with the second end of the normally closed contact of the K3578; the coil of K1 is connected in a self-test control loop.
In the above scheme design, the conduction of the self-checking control loop enables the coil of the K1 to be conducted, so that the normally closed contact of the K1 is opened, the original measuring loop is opened, and the normally open contact of the K1 is closed, so that the normally open contact of the K1, the D1, the R1 and the R2 in the measuring loop and the injected direct current source form a current loop, namely the self-checking loop. Therefore, the self-checking loop can be switched on or off only by controlling the switching on or off of the self-checking control loop, and the self-checking of the measuring loop is carried out when the self-checking loop is switched on. The self-checking control loop can be implemented by referring to the prior art, such as by adopting a combination of a controllable switch and a controller chip.
The utility model discloses the self-checking principle to measuring circuit does, control relay K1 coil switches on, former measuring circuit disconnection, pour into the direct current source, R2, R1, D1, form the current loop between the K1 normally open contact, and the current loop is through the normally open contact connection rotor macroaxis after K1 is closed, the break-over through the controllable switch S on the control resistance this moment, detect the change that the rotor leaks current under S disconnection and S switch on two kinds of operating modes simultaneously, can judge whether unusual measuring circuit.
Optionally, the self-checking control loop further includes a controller, the K1 coil is connected to a power supply, and the controller controls the power supply to switch on/off the output power of the K1 coil, so as to control the power-on or power-off of the K1 coil. Specifically, the controller may adopt an existing microcontroller chip, and the implementation manner of controlling the power output state of the power supply to the K1 coil by the controller may be: the operation of the power supply module is directly controlled, or a controllable switch is arranged on a power supply transmission line of the K1 coil and the power supply, and the controller controls the controllable switch, and the like.
Further, in order to make the measurement circuit when the rotor is excited by force, the positive pole takes place metallicity ground connection, can avoid heavy current to flow through the measurement circuit and cause the measurement circuit components and parts to damage, the utility model discloses in:
the direct current injection type rotor ground protection measuring circuit further comprises a forced excitation protection circuit, wherein the forced excitation protection circuit comprises a relay K2 and a rotor voltage detection unit, the relay K2 comprises a normally closed contact, and the normally closed contact is connected in series in the direct current injection type rotor ground protection measuring circuit and is positioned between the negative pole of the rotor and the large shaft of the rotor; two ends of a coil of the relay K2 are connected with the rotor voltage detection unit; the rotor voltage detection unit is connected with the positive pole and the negative pole of the rotor to detect the rotor voltage, and the positive pole and the negative pole of the rotor are communicated with the coil of the relay K2 according to the comparison result of the rotor voltage and the set voltage threshold value, so that a current loop is formed between the rotor winding and the coil of the relay K2 through the rotor voltage judgment unit.
The utility model discloses in, rotor voltage detecting element can adopt the relevant circuit that has voltage detection and the comparison function of switching on, perhaps the form that electronic circuit and control chip combined together.
Optionally, a first end of a normally closed contact of the relay K2 is connected with the negative electrode of the rotor, a second end of the normally closed contact of the relay K1 is connected with a first end of the normally closed contact of the relay K3578, and then the normally closed contact of the relay K2 is connected with the large shaft of the rotor after passing through a diode, at least two resistors and an injection direct current source in a measurement loop.
Optionally, the rotor voltage detection unit includes a resistor R3, a resistor R4, and a voltage regulator tube D2, the first end of the R3 is connected to the positive pole of the rotor, the second end is connected to the cathode of the D2, the anode of the D2 is connected to one end of the coil of the relay K2, the first end of the R4 is connected between the R3 and the D2, and the second end is connected to a connection line between the negative pole of the rotor and the other end of the coil of the relay K2.
In the above scheme design, the resistance values of the resistors R3 and R4 and the voltage stabilization value of the voltage regulator tube D2 determine the conduction threshold value of the rotor voltage detection unit, the resistance values of the resistors R3 and R4 and the voltage stabilization value of the voltage regulator tube D2 are adjusted, and the forced excitation voltage threshold value can be set, and if the voltage stabilization value of D2 is V2, the forced excitation voltage threshold value is V2 × (R3+ R4)/R4. When strong excitation and metallic grounding do not occur, the rotor voltage detection unit is not conducted, the normally closed contact of the relay K2 is in a closed state, the measurement loop can normally work, when the strong excitation and metallic grounding occur, the rotor voltage reaches a conduction threshold value, the coil of the relay K2 is electrified, the normally closed contact is disconnected, the measurement loop is disconnected, and therefore damage to components and parts due to the fact that large current flows through the measurement loop is avoided.
Furthermore, the positive pole and the negative pole of the rotor are connected with the rotor voltage detection unit through a rectifier bridge circuit; the input end of the rectifier bridge circuit is respectively connected with the anode and the cathode of the rotor, and the output end of the rectifier bridge circuit is respectively connected with the first end of the resistor R3 and the second end of the resistor R4.
In the above scheme design, the rectifier bridge circuit is designed so that the voltage output to the rotor detection unit is a positive value no matter whether the positive electrode and the negative electrode of the rotor are reversely connected, and the fault tolerance of the reverse connection of the positive electrode and the negative electrode of the forced excitation protection circuit can be increased.
Further, the relay K2 further includes a normally open contact, and the normally open contact is connected in series in the forced excitation state signal output loop. Under the design of the scheme, the collection of the forced excitation state signal can be realized only by connecting the forced excitation state signal output loop with an I/O pin of a processor chip.
Furthermore, an alarm is connected in the strong excitation state signal output loop, and the close of the normally open contact of the relay K2 enables the strong excitation state signal output loop to be conducted, so that the alarm is triggered to output an alarm signal.
Advantageous effects
Compared with the prior art, the utility model has the advantages of it is following and progress:
(1) through the self-checking circuit, the self-checking function of the direct-current injection type rotor grounding protection measuring circuit can be provided, and protection refusing caused by failure of the grounding protection measuring circuit is prevented;
(2) the rotor voltage can be monitored in real time through the forced excitation protection circuit, and when the rotor is subjected to forced excitation, the grounding protection measurement circuit is automatically disconnected to prevent circuit components and parts caused by anode grounding during the forced excitation from being damaged. And the fault tolerance of the forced excitation protection circuit can be improved by collecting the rotor voltage through the rectifying circuit, and the forced excitation protection circuit can be ensured to work correctly under the condition that the positive electrode and the negative electrode of the rotor are reversely connected.
Drawings
FIG. 1 is a schematic diagram of a DC injection rotor ground protection measurement circuit;
fig. 2 is a schematic diagram of a self-checking circuit of the present invention;
fig. 3 is a schematic diagram of the forced excitation protection circuit of the present invention;
fig. 4 is a schematic diagram of the forced excitation protection circuit and the self-checking circuit of the present invention;
fig. 5 is a schematic circuit diagram of an embodiment of a rotor voltage detecting unit according to the present invention;
fig. 6 is a schematic circuit diagram of a second embodiment of the present invention.
Detailed Description
The following further description is made in conjunction with the accompanying drawings and the specific embodiments.
Referring to fig. 1, the direct current injection type rotor ground protection measurement circuit includes a direct current injection power supply E, a resistor R1, a resistor R2, and a diode D1, wherein two ends of the resistor R1 or the resistor R2 are connected in parallel with an electronic switch S1, during normal measurement, the electronic switch S1 is controlled to open and close the resistor connected in parallel with the short circuit at a fixed frequency, and then the rotor ground resistance Rg can be calculated by measuring the rotor leakage current under two working conditions of the open and close of the electronic switch S1, so as to realize the direct current injection type rotor ground protection function. When the rotor grounding does not occur, the measuring loop has no passage, the leakage current of the rotor is zero, and when the rotor grounding occurs, the rotor grounding protection is started according to the comparison result of the leakage current of the rotor and the protection setting value.
In order to realize the self-checking and the forced excitation protection of the measuring loop under the condition of the forced excitation of the generator and the metallic grounding of the rotor, the utility model provides a corresponding self-checking circuit and a forced excitation circuit.
Example 1
In order to realize the self-checking of the measuring circuit, the present embodiment describes a self-checking circuit suitable for the dc injection type rotor ground protection measuring circuit, and referring to fig. 2, the self-checking circuit includes a relay K1, and a relay K1 includes a normally closed contact and a normally open contact; the first end of a normally closed contact of K1 is connected with the negative pole of the rotor, and the second end is connected with the rotor main shaft after being injected into a direct current source through D1, R1 and R2; the first end of a normally open contact of the K1 is connected with the rotor large shaft, and the second end of the normally open contact of the K1 is connected with the second end of the normally closed contact of the K3578; the coil of K1 is connected in a self-test control loop.
The conduction of the self-checking control loop enables the K1 coil to be conducted, so that the K1 normally closed contact is disconnected, the original measuring loop is disconnected, the K1 normally open contact is closed, the K1 normally open contact, the D1, the R1 and the R2 in the measuring loop and the injected direct current source form a current loop, namely the self-checking loop, and the current loop is connected with the rotor large shaft through the normally open contact after the K1 is closed. Therefore, the self-checking loop can be switched on or off only by controlling the switching on or off of the self-checking control loop, and the self-checking of the measuring loop is carried out when the self-checking loop is switched on. The self-checking control loop can be implemented by referring to the prior art, such as by adopting a combination of a controllable switch and a controller chip.
The utility model discloses the self-checking principle to measuring circuit does, through the state that changes self-checking control signal ZJI, changes switching on or breaking off of self-checking control circuit promptly, can make measuring circuit switch between self-checking attitude and test attitude. The coil of the relay K1 is controlled to be conducted, the original measuring loop is disconnected, namely, the measuring loop enters a self-checking state, a direct current source, R2, R1, D1 and K1 normally-open contacts are injected to form a current loop, and at the moment, the on or off of a controllable switch S on R1 is controlled, and the change of the leakage current of the rotor under two working conditions of S off and S on is detected at the same time, so that whether the measuring loop is abnormal or not can be judged. If under the self-checking state, the leakage current of the rotor under the S disconnection or conduction working condition is not zero, and a certain proportional relation is met, such as:Idisconnect / IConduction ofIn practical application, R1= R2, when the leakage current of the rotor at S off is half of that at S on, the circuit is normal, otherwise, the circuit is abnormal, and alarm information needs to be sent and protection needs to be locked.
In the invention, the self-checking range is changed along with the short-circuit range of the self-checking loop: if K1 is close to D1, the self-checking of the measurement hardware can be realized, if an electronic switch S1 in a measurement loop is damaged, and leakage current does not change along with the change of an S1 control signal, the damage of S1 can be self-checked; if K1 is close to the rotor negative pole as much as possible, the first end of the normally open contact of K1 is directly connected with the rotor large shaft through another cable, the whole measuring loop can be self-checked, because the rotor leakage current is no longer 0 at the moment, and can be changed along with the switching of the S1 state, but when the measuring loop is broken, the rotor leakage current is always 0, and the fault of the measuring loop can be self-checked.
Example 2
The present embodiment describes a strong excitation protection circuit suitable for a dc injection type rotor ground protection measurement circuit, and as shown in fig. 3, the strong excitation circuit includes a relay K2 and a rotor voltage detection circuit QLJ.
The rotor voltage detection circuit QLJ comprises a resistor R3, a resistor R4 and a voltage regulator tube D2, wherein the positive pole of the rotor is connected with one end of the resistor R3 in a positive input mode, the other end of the resistor R3 is connected with one end of the resistor R4 and the negative pole of the voltage regulator tube D2, the negative pole of the rotor is connected with the other end of the resistor R4 in a negative input mode, and the positive pole of the voltage regulator tube D2 outputs a forced excitation signal QL.
The large rotor shaft is connected with the cathode of the common end of a direct current injection power supply E, the anode of the direct current injection power supply E is connected with one end of a resistor R2, a resistor R2, a resistor R1 and the anode of a diode D1 are sequentially connected in series, the cathode of the diode D1 is connected with one end of a normally closed node of a relay K2, and the other end of the normally closed node of the relay K2 is connected with the cathode of the rotor; the rotor positive pole and the rotor negative pole are connected into the rotor voltage judgment loop QLJ, and the rotor voltage judgment loop QLJ outputs a forced excitation signal QL, so that the K2 normally-closed contact is disconnected, and the large current does not pass through the components of the measurement loop any more.
Adjusting the resistance values of the resistor R3 and the resistor R4 and the voltage stabilization value of the voltage stabilizing tube D2, and setting a forced excitation voltage threshold value, wherein when the rotor voltage is smaller than the forced excitation voltage threshold value, a forced excitation signal QL is 0, a direct-current injection type rotor ground protection measurement loop is connected to a rotor negative electrode, and the loop can normally measure and calculate the ground resistance; when the rotor voltage is greater than the forced excitation voltage threshold value, the forced excitation signal QL is 1, the direct-current injection type rotor grounding protection measurement loop is disconnected, only the loop self-checking function is provided, and the damage of measurement loop components and parts caused by anode grounding during rotor forced excitation is prevented.
In order to facilitate detection of the forced excitation signal, the normally open contact of the relay K2 is provided in this embodiment, when the QL is output, the normally open contact K2 is closed, and when the normally open contact is connected in series in a loop, detection of the switching state of the normally open contact can be realized, and the normally open contact of the relay K2 outputs the forced excitation state QLO for protection logic judgment, so that control execution of subsequent forced excitation protection actions is facilitated.
Example 3
On the basis of embodiment 2, in this embodiment, referring to fig. 4, the positive and negative poles of the rotor are connected to the rotor voltage determination circuit QLJ through the rectification circuit ZL, and at this time, the output voltage is a positive value regardless of whether the positive and negative poles of the rotor are reversely connected, so that the fault tolerance of the forced excitation protection circuit in the reverse connection of the positive and negative poles is increased.
Example 4
Referring to fig. 6, this embodiment includes the scheme designs of embodiments 2 and 3 for a direct-current injection type rotor ground protection measurement circuit with a forced excitation protection function and a self-checking function, and the forced excitation protection and the self-checking of the measurement circuit can also be realized by using the combination scheme of embodiments 1 and 3.
In fig. 6, the rotor big shaft is connected to the negative pole of the dc injection power supply E, the positive pole of the dc injection power supply E is connected to one end of a resistor R2, the other end of a resistor R2 is connected to one end of a resistor R1, the other end of a resistor R1 is connected to the positive pole of a diode D1, the negative pole of a diode D1 is connected to one end of a normally closed node of a relay K1 and one end of a normally open node of a relay K1, the other end of the normally closed node of a relay K1 is connected to one end of a normally closed node of a relay K2, and the other end of the normally closed node; the other end of the normally open node of the relay K1 is connected with the rotor large shaft, and the input coil of the relay K1 is connected with a self-checking control signal ZJI; the positive pole and the negative pole of the rotor are connected with the input of a rectifier circuit ZL, the positive output of the rectifier circuit ZL is connected with one end of a resistor R3, the other end of a resistor R3 is connected with one end of a resistor R4 and the negative pole of a voltage regulator tube D2, the negative output of the rectifier circuit ZL is connected with the other end of the resistor R4, the positive pole of a voltage regulator tube D2 outputs a strong excitation signal QL, the strong excitation signal QL is connected with an input coil of a relay K2, and the normally open contact of the relay K2 outputs a strong excitation QLO signal.
In the above embodiment, the forced excitation protection circuit and the self-checking circuit can provide a self-checking function of the direct-current injection type rotor ground protection measurement circuit, prevent protection rejection caused by failure of the ground protection measurement circuit, and can also monitor the rotor voltage in real time.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, a plurality of modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be considered as the protection scope of the present invention.
Claims (8)
1. A self-checking circuit suitable for direct current injection type rotor ground protection measuring circuit comprises an injection direct current source E, at least two resistors R1 and R2, a controllable switch and a diode D1, wherein the injection direct current source E is connected between a rotor large shaft and a rotor negative electrode in series, and the controllable switch and the diode D1 are connected to two ends of one resistor in parallel; the method is characterized in that:
the self-checking circuit comprises a relay K1, and a relay K1 comprises a normally closed contact and a normally open contact; a first end of a normally closed contact of K1 is connected with the negative electrode of the rotor, and a second end of the normally closed contact is connected with the injection direct current source, the diode and the at least two resistors in the measuring loop in series and then connected with the large shaft of the rotor; the first end of a normally open contact of the K1 is connected with the rotor large shaft, and the second end of the normally open contact of the K1 is connected with the second end of the normally closed contact of the K3578; the coil of K1 is connected in a self-test control loop.
2. The self-test circuit suitable for the DC injection type rotor grounding protection measurement loop as claimed in claim 1, wherein: the self-checking control loop further comprises a controller, the K1 coil is connected with a power supply, and the controller controls the power supply to switch on and off the output power of the K1 coil, so that the K1 coil is controlled to be powered on or off.
3. The self-test circuit suitable for the direct current injection type rotor ground protection measurement circuit as claimed in claim 1 or 2, wherein: the direct current injection type rotor ground protection measuring circuit further comprises a forced excitation protection circuit, wherein the forced excitation protection circuit comprises a relay K2 and a rotor voltage detection unit, the relay K2 comprises a normally closed contact, and the normally closed contact is connected in series in the direct current injection type rotor ground protection measuring circuit and is positioned between the negative pole of the rotor and the large shaft of the rotor; two ends of a coil of the relay K2 are connected with the rotor voltage detection unit; the rotor voltage detection unit is connected with the positive pole and the negative pole of the rotor to detect the rotor voltage, and the positive pole and the negative pole of the rotor are communicated with the coil of the relay K2 according to the comparison result of the rotor voltage and the set voltage threshold value, so that a current loop is formed between the rotor winding and the coil of the relay K2 through the rotor voltage judgment unit.
4. The self-test circuit suitable for the DC injection type rotor grounding protection measurement loop as claimed in claim 3, wherein: the first end of the normally closed contact of the relay K2 is connected with the negative electrode of the rotor, the second end of the normally closed contact of the relay K1 is connected with the first end of the normally closed contact of the relay K2, and then the normally closed contact of the relay K1 is connected with the large shaft of the rotor after passing through a diode, at least two resistors and an injection direct current source in a measuring loop.
5. The self-test circuit suitable for the DC injection type rotor grounding protection measurement loop as claimed in claim 3, wherein: the rotor voltage detection unit comprises a resistor R3, a resistor R4 and a voltage regulator tube D2, wherein the first end of R3 is connected with the positive electrode of the rotor, the second end of R3 is connected with the cathode of D2, the anode of D2 is connected with one end of a coil of a relay K2, the first end of R4 is connected between R3 and D2, and the second end of R4 is connected with a connecting wire between the negative electrode of the rotor and the other end of the coil of the relay K2.
6. The self-test circuit suitable for the DC injection type rotor grounding protection measurement loop as claimed in claim 5, wherein: the positive pole and the negative pole of the rotor are connected with the rotor voltage detection unit through a rectifier bridge circuit; the input end of the rectifier bridge circuit is respectively connected with the anode and the cathode of the rotor, and the output end of the rectifier bridge circuit is respectively connected with the first end of the resistor R3 and the second end of the resistor R4.
7. The self-test circuit suitable for the DC injection type rotor grounding protection measurement loop as claimed in claim 3, wherein: the relay K2 also comprises a normally open contact which is connected in series in the strong excitation state signal output loop.
8. The self-test circuit suitable for the DC injection type rotor grounding protection measurement loop as claimed in claim 7, wherein: still be connected with the alarm in the strong state signal output circuit of encouraging, the closure of relay K2 normally open contact makes the strong state signal output circuit switch on, and then triggers the alarm and output alarm signal.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021493661.XU CN212989624U (en) | 2020-07-24 | 2020-07-24 | Self-checking circuit suitable for direct current injection type rotor ground protection measurement loop |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202021493661.XU CN212989624U (en) | 2020-07-24 | 2020-07-24 | Self-checking circuit suitable for direct current injection type rotor ground protection measurement loop |
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| CN212989624U true CN212989624U (en) | 2021-04-16 |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111952934A (en) * | 2020-07-24 | 2020-11-17 | 南京国电南自电网自动化有限公司 | Strong excitation protection circuit suitable for direct current injection type rotor ground protection measurement circuit |
| CN113741290A (en) * | 2021-09-08 | 2021-12-03 | 世邦通信股份有限公司 | I/O real-time monitoring circuit and monitoring method |
| CN113777478A (en) * | 2021-05-31 | 2021-12-10 | 北京航天光华电子技术有限公司 | Comprehensive self-checking method of automatic tester |
| CN115616968A (en) * | 2022-12-16 | 2023-01-17 | 湖南高至科技有限公司 | Multi-channel activation control device |
-
2020
- 2020-07-24 CN CN202021493661.XU patent/CN212989624U/en active Active
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111952934A (en) * | 2020-07-24 | 2020-11-17 | 南京国电南自电网自动化有限公司 | Strong excitation protection circuit suitable for direct current injection type rotor ground protection measurement circuit |
| CN111952934B (en) * | 2020-07-24 | 2023-03-21 | 南京国电南自电网自动化有限公司 | Strong excitation protection circuit suitable for direct current injection type rotor ground protection measurement circuit |
| CN113777478A (en) * | 2021-05-31 | 2021-12-10 | 北京航天光华电子技术有限公司 | Comprehensive self-checking method of automatic tester |
| CN113741290A (en) * | 2021-09-08 | 2021-12-03 | 世邦通信股份有限公司 | I/O real-time monitoring circuit and monitoring method |
| CN115616968A (en) * | 2022-12-16 | 2023-01-17 | 湖南高至科技有限公司 | Multi-channel activation control device |
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