Converter valve optical loop performance detection device

Abstract

The invention relates to a converter valve optical loop performance detection device, and belongs to the technical field of direct current transmission converter valves. The optical receiving module comprises a comparator, and a first voltage division loop and a second voltage division loop which are connected in series with at least two voltage division resistors; at least one voltage dividing resistor in the first voltage dividing loop is connected in parallel with the switch branch; the positive input end of the comparator is connected with a branch circuit which is used for collecting a potential greater than 0 at a first set position on the first voltage division loop and a potential greater than 0 at a second set position on the second voltage division loop respectively; the negative input end of the branch circuit is connected with a branch circuit which is used for collecting a potential greater than the potential at the first set position on the first voltage division loop and a potential smaller than the potential at the second set position and greater than 0 on the second voltage division loop; the switch branch is used for controlling the switching of the divider resistors connected in parallel to adjust potential values collected by the positive input end and the negative input end from the first divider loop, and the second divider loop is further connected in series with a conversion device used for converting a back-detection optical signal into current.

Description

Technical Field

[0001] The invention relates to a converter valve optical circuit performance detection device, belonging to the technical field of direct current transmission converter valves. Background Art

[0002] Ultra-high voltage direct current (UHVDC) refers to direct current transmission and related technologies at voltage levels of ±800kV and above. In recent years, UHVDC technology has developed rapidly. Many UHVDC projects have been built and put into operation in China, which has greatly solved the problem of domestic electricity shortage. In recent years, the hub role of high-voltage power grid has become more prominent, and it will play a more active role in my country's energy sector.

[0003] The converter valve is the core key equipment of DC power transmission, and the converter valve control equipment is the control and monitoring unit of the converter valve equipment. The stability and reliability of the valve control equipment operation will directly determine the availability of the DC system. The converter valve control equipment and the converter valve thyristor level transmit information through optical signals. Each thyristor level has two signals, and each 12-pulse converter valve system has no less than 1440 signals to control the thyristor triggering. In the long-term operation of the converter valve, it is inevitable that the triggering and return detection light intensity will weaken due to the individual attenuation of optical devices, optical fibers, optical distributors, etc. in the optical communication circuit. The performance of the optical communication circuit determines the reliable triggering of the thyristor and affects the stability of the DC system. Therefore, in order to maintain the stability of the DC system, it is necessary to detect the optical communication circuit. At present, it is difficult for traditional detection methods to adjust the detection limit according to the needs for some minor faults, resulting in the detection results being difficult to adapt to the detection needs of different fault levels. Summary of the invention

[0004] The purpose of the present invention is to provide a converter valve optical circuit performance detection device to solve the problem that the current detection means for optical communication circuits are difficult to adjust the fault detection limit according to demand, resulting in the detection results being difficult to adapt to the detection requirements of different fault degrees.

[0005] In order to solve the above technical problems, the present invention provides a device for detecting the performance of a converter valve optical circuit, comprising: an optical receiving module including a comparator and first and second voltage-dividing circuits each having at least two voltage-dividing resistors in series; at least one voltage-dividing resistor in the first voltage-dividing circuit is connected in parallel with a switch branch; the positive input end of the comparator is connected with branches respectively used to collect a potential greater than 0 at a first set position on the first voltage-dividing circuit and a potential greater than 0 at a second set position on the second voltage-dividing circuit; the negative input end is connected with branches respectively used to collect a potential greater than the first set position on the first voltage-dividing circuit and a potential less than the second set position and greater than 0 on the second voltage-dividing circuit; the switch branch is used to control the switching of the parallel voltage-dividing resistors to adjust the potential values ​​collected by the positive and negative input ends from the first voltage-dividing circuit to adjust the receiving sensitivity of the return detection optical signal of the optical circuit; and the second voltage-dividing circuit is also connected in series with a conversion device for converting the return detection optical signal into a current.

[0006] Furthermore, a switch tube is connected in series on the switch branch, and the switch tube is used to turn on or off accordingly when different level signals are input to the control end of the switch tube, so as to correspondingly turn on or off the switch branch to control the switching of the parallel voltage divider resistor.

[0007] Furthermore, it also includes an optical sending module, which includes a circuit with a light-emitting device and a driving MOS tube in series, the light-emitting device is used to send a trigger light signal of the optical circuit, and the S level of the driving MOS tube is also connected in series with a resistor to form a current negative feedback with the MOS tube; the driving MOS tube is used to adjust the light power of the light-emitting device by adjusting the voltage of its own G level to adjust the power of the trigger light signal of the optical circuit.

[0008] Furthermore, an operational amplifier is connected in series to a branch connected to the positive input end and used for collecting a potential greater than 0 at a first set position of a voltage-dividing resistor on a branch of the first voltage-dividing loop, so as to improve collection accuracy and reduce offset range.

[0009] Furthermore, an operational amplifier is connected in series to a branch connected to the negative input terminal and used for collecting a potential on the first voltage-dividing loop that is greater than the potential at the first set position, so as to improve the collection accuracy and reduce the offset range.

[0010] Furthermore, at least one voltage-dividing resistor in the second voltage-dividing loop has capacitors connected in parallel at both ends, and the capacitors are used for filtering.

[0011] Beneficial effect: The present invention provides a new device for detecting the performance of the optical circuit of a converter valve. The present invention utilizes the comparator of the optical receiving module of the device to respectively collect the potentials of the upper set positions of the first voltage-dividing circuit and the second voltage-dividing circuit. By utilizing the flipping property of the comparator in the prior art, it can be obtained that when the difference between the level of the positive input terminal and the level of the negative input terminal of the comparator is greater than a certain value (which is also equivalent to when the difference between the potential difference of the collected second voltage-dividing circuit and the potential difference of the first voltage-dividing circuit is greater than a certain value), the current output by the conversion device triggers the output signal of the comparator to flip; the current output by the conversion device for converting the return detection optical signal of the optical circuit into current can The magnitude of the potential difference on the second voltage-dividing circuit can be determined. By controlling the switch branch and switching on the resistor connected in parallel with the switch branch, the potential value of the first voltage-dividing circuit is adjusted, thereby adjusting the potential difference of the first voltage-dividing circuit. Cutting out the resistor connected in parallel with the switch branch can make the potential difference of the first voltage-dividing circuit collected larger, thereby making the minimum threshold of the current output by the conversion device that triggers the output signal of the comparator to flip larger, and adjusting the sensitivity of the light receiving detection to a lower level (equivalent to increasing the corresponding threshold for determining the detection of the return detection light signal), so that the condition for triggering the output signal of the comparator to flip is stricter, and it is easier to detect the more severe in the light circuit of the converter valve. Minor faults. On the contrary, the resistor connected in parallel with the switch branch can make the potential difference of the collected first voltage divider circuit smaller, so that the minimum threshold of the current output by the conversion device that triggers the output signal of the comparator to flip is smaller, and the sensitivity of the light receiving detection is adjusted to a higher degree (equivalent to lowering the corresponding threshold for determining the detection of the return light signal). Then, the condition for triggering the output signal of the comparator to flip is looser, and it is not easy to detect minor faults in the optical circuit of the converter valve, that is, minor faults in the optical circuit will not lead to abnormal results of the optical circuit performance detection, that is, minor faults in the optical circuit can be ignored, avoiding the influence of insignificant minor faults. The detection result is affected by the control of the switch circuit to control the input of the resistor in the first voltage-dividing loop, so that the sensitivity of the light receiving detection is adjusted to a higher level according to the demand, so that the detection device can be adjusted to a state that meets the detection requirement of lower fault detection accuracy; at the same time, the switch circuit can also be controlled to control the cut-out of the resistor in the first voltage-dividing loop, so that the sensitivity of the light receiving detection is adjusted to a relatively high level according to the demand, so that the detection device can be adjusted to a state that meets the detection requirement of relatively higher fault detection accuracy, thereby realizing flexible adaptation to the detection requirements of different fault degrees. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a schematic diagram of a converter valve optical circuit performance detection device in an embodiment of the converter valve optical circuit performance detection device of the present invention; Figure 2It is a circuit principle diagram of an optical receiving module of a converter valve optical circuit performance detection device in an embodiment of the converter valve optical circuit performance detection device of the present invention; Figure 3 It is a circuit principle diagram of an optical transmission module of a converter valve optical circuit performance detection device in an embodiment of the converter valve optical circuit performance detection device of the present invention. DETAILED DESCRIPTION

[0013] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings.

[0014] Embodiment of the device for detecting the performance of the optical circuit of the converter valve The present embodiment provides a device for detecting the performance of a converter valve optical circuit, comprising: an optical receiving module including a comparator and first and second voltage-dividing circuits each having at least two voltage-dividing resistors in series; at least one voltage-dividing resistor in the first voltage-dividing circuit is connected in parallel with a switch branch; a positive input end of the comparator is connected with branches respectively used to collect a potential greater than 0 at a first set position on the first voltage-dividing circuit and a potential greater than 0 at a second set position on the second voltage-dividing circuit; a negative input end is connected with branches respectively used to collect a potential greater than the first set position on the first voltage-dividing circuit and a potential less than the second set position and greater than 0 on the second voltage-dividing circuit; the switch branch is used to control the switching of the parallel voltage-dividing resistors to adjust the potential values ​​collected by the positive and negative input ends from the first voltage-dividing circuit to adjust the receiving sensitivity of the return detection optical signal of the optical circuit; and a conversion device for converting the return detection optical signal into a current is also connected in series with the second voltage-dividing circuit. The detection device can control the input of the resistor on the first voltage divider loop by controlling the switch circuit, so that the sensitivity of the light receiving detection can be adjusted to a higher degree according to the demand, so that the detection device can be adjusted to a state that meets the detection requirements of lower fault detection accuracy; at the same time, it can also control the cut-out of the resistor on the first voltage divider loop by controlling the switch circuit, so that the sensitivity of the light receiving detection can be adjusted to a relatively low degree according to the demand, so that the detection device can be adjusted to a state that meets the detection requirements of relatively higher fault detection accuracy, thereby achieving flexible adaptation to the detection requirements of different fault degrees. The following is a specific description: The schematic diagram of the converter valve optical circuit performance detection device is as follows: Figure 1As shown, the converter valve optical circuit performance detection device includes an optical sending module and an optical receiving module. The main control unit in the converter valve control device sends a trigger optical signal to the MSC (multi-mode star coupler) in the valve assembly through the trigger signal sending unit (optical sending module, also called optical sending circuit). The MSC mixes the received multi-path optical signals evenly and sends them to the thyristors in multiple paths. After the thyristors are triggered, they send back the detection optical signal to the feedback signal receiving unit (optical receiving module, also called optical receiving circuit). When the output signal of the comparator in the optical receiving circuit is flipped, the performance of the optical circuit is normal (that is, the detection result indicates that the converter valve optical circuit is not faulty). Otherwise, the performance of the optical circuit is abnormal (that is, the detection result indicates that the converter valve optical circuit is faulty).

[0015] The circuit schematic diagram of the optical receiving module of the converter valve optical circuit performance detection device is as follows: Figure 2 As shown, the optical receiving module includes a comparator and a first and a second voltage dividing circuit each having at least two voltage dividing resistors in series, the first voltage dividing circuit (corresponding to Figure 2 The left half of the figure) has a switch branch connected in parallel at both ends of at least one voltage-dividing resistor. In this embodiment, the switch branch is connected in parallel at both ends of the voltage-dividing resistor R56; at least one voltage-dividing resistor in the second voltage-dividing loop has a capacitor connected in parallel at both ends. The capacitor is used for filtering. In this embodiment, the capacitor C71 used for filtering is connected at both ends of the voltage-dividing resistor R305. The positive input end of the comparator is connected to the potential greater than 0 at the first set position on the first voltage-dividing loop and the potential greater than 0 at the second voltage-dividing loop (corresponding to the voltage-dividing loop). Figure 2 The negative input terminal is connected to a branch for collecting a potential greater than the first set position on the first voltage-dividing circuit and a potential less than the second set position and greater than 0 on the second voltage-dividing circuit; wherein the collected potential refers to the collected potential value; the switch branch is used to control the switching of the voltage-dividing resistors connected in parallel to adjust the potential values ​​collected from the first voltage-dividing circuit by the positive and negative input terminals; the second voltage-dividing circuit is also connected in series with a conversion device for converting the return detection optical signal of the optical circuit into a current. In this embodiment, the conversion device is a photosensitive diode. In other embodiments, the conversion device may also be other photoelectric conversion devices, as long as the return detection optical signal of the optical circuit can be converted into a current. A switch tube is connected in series on the switch branch. The switch tube is used to turn on or off accordingly when different level signals are input to the control end of the switch tube, so as to control the switching of the parallel voltage divider resistor by correspondingly connecting or disconnecting the switch branch. In this embodiment, the switch tube is a triode (NPN type). In other embodiments, the switch tube can also be other models as long as it can be automatically disconnected or connected by the signal of the control end.

[0016] The positive input terminal is connected to a branch for collecting a potential greater than 0 at a first set position of a voltage-dividing resistor on a branch of a first voltage-dividing loop, and an operational amplifier (such as Figure 2 The operational amplifier circuit corresponding to U7B in the figure is used to improve the acquisition accuracy and reduce the offset range. The branch connected to the negative input terminal for collecting the potential greater than the potential at the first set position on the first voltage divider loop is also connected in series with an operational amplifier (such as Figure 2 The operational amplifier circuit corresponding to U7A in FIG. 1 is also used to improve the acquisition accuracy and reduce the offset range.

[0017] Specifically, after the photodiode outputs dark current, when the difference between the level of the positive input terminal and the level of the negative input terminal of the comparator is greater than 5mv ( Figure 2 When the difference between the level of pin 3 and pin 2 of the comparator is greater than 5mv), the current output by the conversion device (photosensitive diode D2) triggers the output signal of the comparator to flip, indicating that a certain intensity of the return detection light signal is detected; when the control end (L-SENS-A) of the NPN transistor inputs a low-level signal, the transistor is not turned on, and the switch branches at both ends of R56 are disconnected, then R56 is put into operation, +UREF-A=3.84V, -UREF-A=3.79V, and the condition for the comparator to flip is that the level of pin 3 exceeds the level of pin 2 by 5mV, so we get: 3.79V+Id*(3.32kΩ+1kΩ)-3.84V-Id*1kΩ>5mV Solved: I d >16.57μA, that is, the photodiode must output at least 16.57μA of dark current to ensure that the output signal of the trigger comparator is flipped; When a high-level signal is input to the control terminal (L-SENS-A) of the transistor, the transistor is turned on, and the switch branches at both ends of R56 are turned on, then R56 is short-circuited, +UREF-A=2.59V, -UREF-A=2.49V, and the condition for the comparator to flip is that the level of pin 3 exceeds the level of pin 2 by 5mV, so we get: 2.49V+Id*(3.32kΩ+1kΩ)-2.59V-Id*1kΩ>5mV Solved: I d>31.66μA, that is, the photodiode must output at least 31.66μA of dark current to ensure that the output signal of the trigger comparator is flipped; when L-SENS-A is at a low level, the resistance in the first voltage-dividing circuit is greater than that in the first voltage-dividing circuit when L-SENS-A is at a high level. When L-SENS-A is at a low level, the comparator is more likely to flip than when L-SENS-A is at a high level. The sensitivity of the received optical signal (the received optical signal is the return detection optical signal received by the optical receiving module, hereinafter referred to as the received optical signal) is higher, the qualified range of the optical circuit performance detection is larger, and slight faults in the optical circuit will not lead to abnormal results of the optical circuit performance detection, that is, slight faults in the optical circuit can be ignored to avoid insignificant minor faults affecting the detection results. On the contrary, the sensitivity of the received optical signal is lower , the qualified range of the optical circuit performance detection is smaller, more subtle faults in the optical circuit can be detected, and the detection accuracy is higher; therefore, the input of the resistor on the first voltage-dividing circuit can be controlled by controlling the switch circuit, so that the sensitivity of the received optical signal can be adjusted to a higher level according to the demand, and the qualified range of the optical circuit performance detection is larger, so that the detection device can be adjusted to meet the detection requirements of relatively low fault detection accuracy and high cost requirements; at the same time, the switching circuit can also be controlled to control the cut-out of the resistor on the first voltage-dividing circuit, so that the sensitivity of the received optical signal can be adjusted to a relatively low level according to the demand, and the qualified range of the optical circuit performance detection is smaller, so that the detection device can be adjusted to meet the detection requirements of high fault detection accuracy, thereby realizing flexible adaptation to the detection requirements of different fault degrees.

[0018] The circuit schematic diagram of the optical transmission module of the converter valve optical circuit performance detection device is as follows: Figure 3 As shown, the optical transmission module is used to send an optical signal to the valve assembly. The optical transmission module includes a circuit in which a light-emitting device and a driving MOS tube are connected in series. The light-emitting device is used to send a triggering optical signal of the optical circuit. The light-emitting power of the light-emitting device is adjusted by adjusting the voltage of the G level of the driving MOS tube to adjust the power of the triggering optical signal of the optical circuit. In this embodiment, the light-emitting device is a laser diode (LED1). In other embodiments, the light-emitting device can also be other devices that can emit light. The power of LED1 depends on the current I flowing through the laser diode. d , id current depends on the voltage V between the G and S stages of the driving MOS tube GSThe S stage driving the MOS tube is also connected to a resistor for forming a current negative feedback with the MOS tube. In this embodiment, the S stage is connected to three resistors in parallel. Connecting multiple resistors in parallel can prevent a single resistor from having too much current, which may damage the resistor. As the current of the MOS tube id increases, the voltage on R increases, Vs increases, and since Vg remains unchanged, Vgs decreases. As Vgs decreases, id decreases, and the conduction channel of the MOS tube becomes smaller, thereby reducing the saturation current and forming a negative feedback. Therefore, the luminous power of LED1 can be adjusted by controlling the voltage Vg of the MOS tube G stage. When Vg increases, the luminous power increases, and when Vg decreases, the luminous power decreases. When performing optical circuit detection, the intensity of the triggering light signal is changed by adjusting the luminous power of the laser diode according to the demand. , and finally adjust the qualified range of the optical circuit performance detection; specifically, the light power of the laser diode can be reduced according to the needs, so that the intensity of the trigger light signal becomes lower, so that the valve assembly of the converter valve is less likely to be triggered, so that the qualified range of the optical circuit performance detection is narrowed, so that it is easier to detect more subtle faults in the optical circuit of the converter valve, and the detection device can meet the detection requirements of higher accuracy of the performance detection of the optical circuit of the converter valve. At the same time, the light power of the laser diode can be increased according to the needs, so that the intensity of the trigger light signal becomes higher, so that the valve assembly of the converter valve is more likely to be triggered, and the qualified range of the optical circuit performance detection is larger, so that the detection device is adjusted to meet the detection requirements of relatively low fault detection accuracy and high cost requirements; thereby, flexible adaptation to detection requirements of different fault degrees is achieved. For example, during the actual optical circuit performance test, the trigger optical signal power of the optical transmitting module can be reduced to half of the original power to narrow the qualified range of the optical circuit performance test, and then the sensitivity of the optical receiving module to receive the return detection optical signal can be correspondingly improved (for example, the switch branch of the optical receiving module can be controlled to input a voltage divider resistor to reduce the minimum current value that can flip the output signal of the comparator to half of the original value) to avoid reducing the trigger optical signal power of the optical transmitting module to half of the original power while the sensitivity of the optical receiving module to receive the return detection optical signal remains unchanged, so that the qualified range of the optical circuit performance test is adjusted too small, resulting in some normal components in the optical circuit or slightly faulty components that can be regarded as normal being misjudged as faulty components; the combination of the two operations can appropriately narrow the qualified range of the optical circuit performance test, making it easier to detect more subtle faults in the converter valve optical circuit. The detection device can meet the detection requirement state of the converter valve optical circuit performance test with higher accuracy.

Claims

1. A device for detecting the performance of a converter valve optical circuit, characterized in that: include: An optical receiving module comprising a comparator and first and second voltage-dividing circuits each having at least two voltage-dividing resistors in series; at least one voltage-dividing resistor in the first voltage-dividing circuit is connected in parallel with a switch branch; a positive input terminal of the comparator is connected to branches for respectively collecting a potential greater than 0 at a first set position on the first voltage-dividing circuit and a potential greater than 0 at a second set position on the second voltage-dividing circuit; The negative input end is connected to branches for collecting a potential greater than the potential at the first set position on the first voltage-dividing loop and a potential less than the potential at the second set position and greater than 0 on the second voltage-dividing loop; the switch branch is used to control the switching of the parallel voltage-dividing resistors to adjust the potential values ​​collected by the positive and negative input ends from the first voltage-dividing loop to adjust the receiving sensitivity of the return detection optical signal of the optical circuit; the second voltage-dividing loop is also connected in series with a conversion device for converting the return detection optical signal into a current.

2. The converter valve optical circuit performance detection device according to claim 1, characterized in that: The switch branch is connected in series with a switch tube, which is used to be turned on or off accordingly when different level signals are input to the control end of the switch tube, so as to correspondingly turn on or off the switch branch to control the switching of the parallel voltage-dividing resistor.

3. The converter valve optical circuit performance detection device according to claim 1 or 2, characterized in that: It also includes an optical sending module, which includes a circuit with a light-emitting device and a driving MOS tube in series, the light-emitting device is used to send a trigger light signal of the optical circuit, and the S level of the driving MOS tube is also connected in series with a resistor to form a current negative feedback with the MOS tube; the driving MOS tube is used to adjust the light power of the light-emitting device by adjusting the voltage of its own G level to adjust the power of the trigger light signal of the optical circuit.

4. The converter valve optical circuit performance detection device according to claim 1, characterized in that: An operational amplifier is connected in series to a branch connected to the positive input end and used for collecting a potential greater than 0 at a first set position of a voltage-dividing resistor on a branch of a first voltage-dividing loop, so as to improve collection accuracy and reduce offset range.

5. The converter valve optical circuit performance detection device according to claim 1, characterized in that: An operational amplifier is connected in series to a branch connected to the negative input terminal and used for collecting a potential on the first voltage-dividing loop that is greater than the potential at the first set position, so as to improve the collection accuracy and reduce the offset range.

6. The converter valve optical circuit performance detection device according to claim 1, characterized in that: At least one voltage-dividing resistor in the second voltage-dividing loop has capacitors connected in parallel at both ends thereof, and the capacitors are used for filtering.

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