Control protection system of amplitude-phase corrector

Abstract

The invention discloses a control protection system of an amplitude-phase corrector, which comprises a power transmission line, a first capacitive circuit, a second capacitive circuit, a resistance branch and a lightning protection circuit, and is characterized in that the first capacitive circuit, the second capacitive circuit, the resistance branch and the lightning protection circuit are arranged on the power transmission line; the power transmission line is connected with the access end of the first capacitive circuit in series, the output end of the first capacitive circuit is respectively connected with the access end of the second capacitive circuit, the access end of the resistor branch and the access end of the lightning protection circuit, and the second capacitive circuit, the resistor branch and the lightning protection circuit are connected in parallel. According to the control protection system of the amplitude-phase corrector provided by the embodiment of the invention, the detection interface is arranged on each circuit branch of the amplitude-phase corrector, so that the running state of the amplitude-phase corrector can be monitored in real time, and current amplitude and phase deviation caused by factors such as line impedance and load change can be avoided, and therefore, the stability and reliability of a whole power system can be ensured.

Description

Technical Field

[0001] The invention relates to the field of flexible direct current power transmission of power systems, and in particular to a control and protection system for an amplitude and phase corrector. Background Art

[0002] Flexible DC transmission technology has been widely used in the power sector due to its advantages of improving power system stability, providing dynamic reactive power support and improving power quality. However, since this technology is based on a power electronics system with fully controlled semiconductor devices, there is a risk of harmonic oscillation when connected to the system, which poses a threat to the safe, stable and reliable operation of the power system.

[0003] In order to deal with this risk, two methods, software suppression measures and hardware suppression measures, have been adopted at home and abroad. Software suppression measures are mainly achieved through impedance reshaping technologies such as additional damping and filtering in the control system, while hardware suppression measures reshape the impedance of the flexible DC transmission system by installing amplitude and phase correctors. As a new hardware device in the flexible DC transmission system, the amplitude and phase corrector plays an important role in suppressing broadband oscillations.

[0004] In order to ensure the safe and stable operation of the amplitude and phase corrector, it is necessary to configure it with corresponding protection functions. These protection functions are designed to monitor the operating status of the amplitude and phase corrector, and promptly detect and handle possible faults or abnormal conditions, thereby ensuring the overall stability and reliability of the flexible DC transmission system.

[0005] In the prior art, the protection of amplitude and phase correctors is mostly based on specific fault types, resulting in a single protection effect. As a protection device of the flexible DC transmission system, how to provide comprehensive protection for the amplitude and phase corrector has become a technical problem that technicians in this field need to solve urgently. Summary of the invention

[0006] The present invention provides a control and protection system for an amplitude-phase corrector to solve the problem of single protection effect of the amplitude-phase corrector and realize all-round protection effect on the amplitude-phase corrector.

[0007] In order to solve the above technical problems, an embodiment of the present invention provides a control and protection system for an amplitude and phase corrector, comprising a transmission line, a first capacitor circuit, a second capacitor circuit, a resistor branch and a lightning protection circuit;

[0008] The first capacitor circuit, the second capacitor circuit, the resistor branch and the lightning protection circuit are all arranged on the transmission line;

[0009] The transmission line is connected in series with an access end of the first capacitor circuit, the output end of the first capacitor circuit is connected to an access end of the second capacitor circuit, an access end of the resistor branch and an access end of the lightning protection circuit respectively, and the second capacitor circuit, the resistor branch and the lightning protection circuit are connected in parallel;

[0010] The first capacitor circuit is used to change the phase difference of the input signal to preliminarily reduce the amplitude and phase error;

[0011] The second capacitor circuit is used to further change the phase response of the transmission line to achieve accurate adjustment of the phase of the input signal;

[0012] The resistor branch is used for resistor overload protection;

[0013] The lightning protection circuit is used for internal fault protection of the amplitude and phase corrector.

[0014] As one of the preferred solutions, the control and protection system of the amplitude and phase corrector further includes a high-voltage side knife switch, a first detection interface, a second detection interface, a third detection interface, a fourth detection interface, a fifth detection interface and a sixth detection interface;

[0015] The high-voltage side knife switch is located on the first capacitor circuit;

[0016] The first detection interface is located between the input end of the transmission line and the high-voltage side knife switch, the second detection interface is located inside the first capacitor circuit, the third detection interface is located inside the second capacitor circuit, the fourth detection interface is located between the lightning protection circuit and the grounding point, the fifth detection interface is located between the output end of the resistance branch and the grounding point, and the fifth detection interface is located between the second capacitor circuit and the grounding point.

[0017] As one of the preferred solutions, the control and protection system of the amplitude and phase corrector further includes a detection circuit;

[0018] The detection input end of the detection circuit is connected to the first detection interface, the second detection interface, the third detection interface, the fourth detection interface, the fifth detection interface and the sixth detection interface respectively.

[0019] As one preferred solution, the detection circuit at least includes a current signal detection device, a voltage signal detection device and a frequency signal detection device;

[0020] The detection end of the current signal detection device is respectively connected to the first detection interface, the fourth detection interface, the fifth detection interface and the sixth detection interface;

[0021] The detection end of the voltage signal detection device is connected to the second detection interface and the third detection interface respectively;

[0022] The detection end of the frequency signal detection device is connected to the first detection interface and the sixth detection interface respectively.

[0023] As one of the preferred solutions, the control and protection system of the amplitude and phase corrector further includes a first communication device, and the first communication device is connected to the output end of the detection circuit.

[0024] As one of the preferred solutions, the control and protection system of the amplitude-phase corrector further includes a second communication device, and the second communication device is connected to the output end of the amplitude-phase corrector circuit.

[0025] As one of the preferred solutions, the control and protection system of the amplitude and phase corrector further includes a cloud storage platform, and the cloud storage platform communicates and interacts with the output end of the detection circuit.

[0026] As one of the preferred solutions, the power transmission line further includes a disconnection protection circuit, and a control end of the disconnection protection circuit is connected to an output end of the detection circuit.

[0027] As one of the preferred solutions, the control end of the disconnect protection circuit is connected to the cloud storage platform.

[0028] As one of the preferred solutions, the control and protection system of the amplitude and phase corrector further includes an alarm device, and the control end of the alarm device is connected to the output end of the detection circuit;

[0029] The alarm device includes a speaker, an LED light group and a remote communication interaction interface, and the remote communication interaction interface is connected to the cloud storage platform.

[0030] Compared with the prior art, the embodiments of the present invention have the following advantages:

[0031] (1) The control and protection system of the amplitude and phase corrector can monitor its operating status in real time by setting detection interfaces on each circuit branch of the amplitude and phase corrector to avoid current amplitude and phase deviation caused by factors such as line impedance and load changes, thereby ensuring the stability and reliability of the entire power system;

[0032] (2) The control and protection system of the amplitude and phase corrector greatly improves the operating safety and reliability of the amplitude and phase corrector by setting up capacitor circuits, resistor branches and lightning protection circuits. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a circuit diagram of an amplitude and phase corrector system in one embodiment of the present invention;

[0034] Figure 2 It is a circuit diagram of specific components and detection interfaces of an amplitude and phase corrector system in one embodiment of the present invention;

[0035] Figure 3 It is a control and protection configuration diagram of an amplitude and phase corrector in one embodiment of the present invention.

[0036] Reference numerals:

[0037] Among them, A, the first capacitor circuit; B, the second capacitor circuit; C, the resistor branch; D, the lightning protection circuit; 1, the high-voltage side knife switch; 2, the first capacitor; 3, the second capacitor; 4, the resistor; 5, the lightning arrester; 6, the first detection interface; 7, the second detection interface; 8, the third detection interface; 9, the fourth detection interface; 10, the fifth detection interface; 11, the sixth detection interface. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] In the description of the present invention, the terms "first", "second", "third", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", "third", etc. may explicitly or implicitly include one or more of the feature. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0040] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the term "and / or" used herein includes any and all combinations of one or more related listed items. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in specific circumstances.

[0041] In the description of the present invention, it should be noted that, unless otherwise defined, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0042] It should be noted in advance that the embodiments of the present invention are applied to the field of flexible direct current transmission of power systems. Flexible direct current transmission technology has been widely used in the power field due to its advantages of improving the stability of power systems, providing dynamic reactive power support and improving power quality. However, since this technology is based on a power electronics system with fully controlled semiconductor devices, there is a risk of harmonic oscillation when connected to the system, which poses a threat to the safe, stable and reliable operation of the power system.

[0043] In order to deal with this risk, two methods, software suppression measures and hardware suppression measures, have been adopted at home and abroad. Software suppression measures are mainly achieved through impedance reshaping technologies such as additional damping and filtering in the control system, while hardware suppression measures reshape the impedance of the flexible DC transmission system by installing amplitude and phase correctors. As a new hardware device in the flexible DC transmission system, the amplitude and phase corrector plays an important role in suppressing broadband oscillations.

[0044] In order to ensure the safe and stable operation of the amplitude and phase corrector, it is necessary to configure it with corresponding protection functions. These protection functions are designed to monitor the operating status of the amplitude and phase corrector, and promptly detect and handle possible faults or abnormal conditions, thereby ensuring the overall stability and reliability of the flexible DC transmission system.

[0045] An embodiment of the present invention provides a control and protection system for an amplitude and phase corrector. For details, see Figure 1 , Figure 1 The circuit diagram of an amplitude and phase corrector system in one embodiment of the present invention is shown, including a transmission line, a first capacitor circuit, a second capacitor circuit, a resistor branch and a lightning protection circuit.

[0046] Specifically, the first capacitor circuit A, the second capacitor circuit B, the resistor branch C and the lightning protection circuit D are all arranged on the transmission line. The transmission line is connected in series with the access end of the first capacitor circuit A. At this time, the first capacitor circuit A is used to change the phase difference of the input signal to preliminarily reduce the amplitude and phase error; the output end of the first capacitor circuit A is respectively connected to the access end of the second capacitor circuit B, the access end of the resistor branch C and the access end of the lightning protection circuit D, and the second capacitor circuit B, the resistor branch C and the lightning protection circuit D are connected in parallel, wherein the second capacitor circuit B is used to further change the phase response of the transmission line to achieve accurate adjustment of the input signal phase; the resistor branch C is used for resistor overload protection; the lightning protection circuit D is used for internal fault protection of the amplitude and phase corrector.

[0047] It should be noted that during the signal transmission process, if the resistor is overloaded, the resistor branch C will play a role in protecting the circuit from damage, but the resistor branch C does not directly participate in the signal transmission, but provides protection under specific conditions (such as overload).

[0048] At the same time, the lightning protection circuit D does not directly participate in the transmission of signals. When a fault occurs inside the amplitude and phase corrector or an abnormal situation such as lightning occurs, the lightning protection circuit D will respond quickly to protect the amplitude and phase corrector and its internal circuits from damage.

[0049] After correction by the first capacitor circuit A and the second capacitor circuit B, the signal is finally output from the amplitude-phase corrector. At this time, the phase and amplitude of the signal have been optimized, and the amplitude-phase error is effectively reduced.

[0050] An embodiment of the present invention provides a control and protection system for an amplitude and phase corrector. For details, see Figure 2 , Figure 2 It is a circuit diagram of specific components and detection interfaces of an amplitude and phase corrector system in one embodiment of the present invention, including a high-voltage side knife switch 1, a first capacitor 2, a second capacitor 3, a resistor 4, a lightning arrester 5, a first detection interface 6, a second detection interface 7, a third detection interface 8, a fourth detection interface 9, a fifth detection interface 10 and a sixth detection interface 11.

[0051] Specifically, in this embodiment, the type and number of detection interfaces are determined according to the topological structure of the amplitude and phase corrector. The first detection interface 6, the second detection interface 7, the third detection interface 8, the fourth detection interface 9, the fifth detection interface 10 and the sixth detection interface 11 are determined according to the structure and layout of the amplitude and phase corrector.

[0052] Among them, the first capacitor circuit A includes a high-voltage side knife switch 1 and a first capacitor 2, the second capacitor circuit B includes a second capacitor 3, the resistance branch C includes a resistor 4, and the lightning protection circuit D includes a lightning arrester 5.

[0053] The high-voltage side knife switch 1 is located on the first capacitor circuit, the first detection interface 6 is located between the input end of the transmission line and the high-voltage side knife switch 1, the second detection interface 7 is located inside the first capacitor 2, the third detection interface 8 is located inside the second capacitor 3, the fourth detection interface 9 is located between the lightning arrester 5 and the grounding point, the fifth detection interface 10 is located between the output end of the resistor 4 and the grounding point, and the fifth detection interface 10 is located between the second capacitor 3 and the grounding point.

[0054] Specifically, the system further includes a first communication device and a cloud storage platform. The output end of the detection circuit 3 is also connected to the cloud storage platform, and the cloud storage platform stores the output results of each detection circuit.

[0055] Specifically, the system also includes an alarm device, the control end of the alarm device is connected to the output end of the detection circuit 3, the alarm device includes a speaker, an LED light group and a remote communication interaction, and the remote communication interaction interface is connected to the cloud storage platform. Specifically, the alarm device refers to a device that can transmit alarm information, which is not specifically limited here.

[0056] When an abnormal situation occurs, the sound alarm and optical alarm will automatically emit sound and light, and different sounds and colors will indicate different alarm levels or types. The alarm unit will communicate with user terminals, cloud storage platforms and other devices via Wi-Fi or Bluetooth connections. Users can take corresponding countermeasures based on the alarm information, such as tripping, isolating faulty equipment, etc., to ensure the safe operation of the amplitude and phase corrector.

[0057] An embodiment of the present invention provides a control and protection system for an amplitude and phase corrector. For details, see Figure 3 , Figure 3 The figure shows a control and protection configuration diagram of an amplitude and phase corrector in one embodiment of the present invention.

[0058] In this embodiment, the head end measuring point, C1 unbalanced measuring point, C2 unbalanced measuring point, lightning arrester measuring point, resistance measuring point and tail end measuring point are respectively used as the first detection interface 6, the second detection interface 7, the third detection interface 8, the fourth detection interface 9, the fifth detection interface 10 and the sixth detection interface 11.

[0059] In this embodiment, the positions of each interface are as follows: the head end measuring point is installed between the amplitude-phase corrector busbar and the high-voltage side switch 1; the C1 unbalanced measuring point is installed on the first capacitor 2; the C2 unbalanced measuring point is installed on the second capacitor 3; the lightning arrester measuring point is installed at the tail of the lightning arrester 5; the resistance measuring point is installed on the resistance branch C; the tail end measuring point is installed before the grounding point of the amplitude-phase corrector.

[0060] The detection circuit at least includes a current signal detection circuit, a voltage signal detection circuit and a frequency signal detection circuit. Specifically, in this circuit, the protection functions of the current signal detection circuit, the voltage signal detection circuit and the frequency signal detection circuit at least include differential protection, overcurrent protection, capacitor unbalance protection, resistor overload protection, reactance overload protection and detuning alarm.

[0061] Differential protection means that when a device fails, the current flowing into the protected device is not equal to the current flowing out, and the differential current is greater than zero. Differential protection is mainly used to protect the transformer from internal short circuit faults and is the main protection for the transformer.

[0062] Assume that the filtered head-end current is 98A, the tail-end current is 95A, and the calculated differential current is 3A. If the differential protection threshold is set to 2A, the differential current exceeds the threshold and the differential protection is activated. According to the current value of the arrester measuring point, determine whether the arrester is discharged. Assuming that the arrester measuring point current is 5A, if the arrester protection threshold is set to 4A, the current exceeds the threshold and the differential protection is activated.

[0063] Overcurrent protection is mainly used to prevent excessive current caused by unexpected situations such as load short circuit, overload or control circuit failure, thereby protecting equipment and circuits.

[0064] Capacitor unbalance protection is a protection method used to monitor capacitor unbalance caused by fuse blowing or capacitor damage in single-phase capacitor banks, and give an alarm or close the bypass switch. This protection method can ensure the normal operation of the capacitor bank and prevent equipment failure caused by capacitor unbalance.

[0065] The capacitor unbalance is calculated by the current values ​​of the C1 unbalance measurement point and the C2 unbalance measurement point. Assuming that the current of the C1 unbalance measurement point is 50A and the current of the C2 unbalance measurement point is 48A, the calculated unbalance is 4%. If the unbalance protection threshold is set to 3%, the unbalance exceeds the threshold and the capacitor unbalance protection is activated.

[0066] The current and power of the resistor branch C are calculated by the current value at the resistor measuring point. Assuming the current at the resistor measuring point is 80A and the resistance value is 10Ω, the calculated power is 6400W. If the resistor overload protection threshold is set to 6000W, the power exceeds the threshold and the resistor overload protection is activated.

[0067] Reactor overload protection refers to the protective measures taken when the current in the reactor or related circuit exceeds its rated value. This protection measure can ensure the normal operation of the reactor and prevent equipment damage or safety accidents caused by overload. The reactor current is calculated based on the current values ​​of the head end measurement point and the tail end measurement point. Assuming that the head end current is 100A and the tail end current is 90A, the calculated reactor current is 10A. If the reactor overload protection threshold is set to 8A, the current exceeds the threshold and the reactor overload protection is activated.

[0068] Detuning alarm is usually used in power systems. When the frequency or phase of the system does not match the set value, the alarm device will be triggered. This alarm method can remind operators to take timely measures to prevent equipment failure or safety accidents caused by system detuning.

[0069] By comparing the current phase difference between the head-end measuring point and the tail-end measuring point, it is determined whether the amplitude phase corrector is detuned. Assuming that the head-end current phase is 0° and the tail-end current phase is -5°, the calculated phase difference is 5°. If the detuning alarm threshold is set to 4°, the phase difference exceeds the threshold and a detuning alarm signal is issued. Throughout the process, data collection, processing and judgment of each measuring point are completed through the automated information system to ensure the timeliness and accuracy of protection.

[0070] Of course, the current values, resistance values, etc. mentioned above are only examples, and the specific threshold values ​​are set according to the working environment.

[0071] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A control and protection system for an amplitude and phase corrector, characterized in that: It includes a power transmission line, a first capacitor circuit, a second capacitor circuit, a resistor branch and a lightning protection circuit; The first capacitor circuit, the second capacitor circuit, the resistor branch and the lightning protection circuit are all arranged on the transmission line; The transmission line is connected in series with an access end of the first capacitor circuit, the output end of the first capacitor circuit is connected to an access end of the second capacitor circuit, an access end of the resistor branch and an access end of the lightning protection circuit respectively, and the second capacitor circuit, the resistor branch and the lightning protection circuit are connected in parallel; The first capacitor circuit is used to change the phase difference of the input signal to preliminarily reduce the amplitude and phase error; The second capacitor circuit is used to further change the phase response of the transmission line to achieve accurate adjustment of the phase of the input signal; The resistor branch is used for resistor overload protection; The lightning protection circuit is used for internal fault protection of the amplitude and phase corrector.

2. The control and protection system of the amplitude and phase corrector according to claim 1, characterized in that: The control and protection system of the amplitude and phase corrector also includes a high-voltage side knife switch, a first detection interface, a second detection interface, a third detection interface, a fourth detection interface, a fifth detection interface and a sixth detection interface; The high-voltage side knife switch is located on the first capacitor circuit; The first detection interface is located between the input end of the transmission line and the high-voltage side knife switch, the second detection interface is located inside the first capacitor circuit, the third detection interface is located inside the second capacitor circuit, the fourth detection interface is located between the lightning protection circuit and the grounding point, the fifth detection interface is located between the output end of the resistance branch and the grounding point, and the fifth detection interface is located between the second capacitor circuit and the grounding point.

3. The control and protection system of the amplitude and phase corrector according to claim 2, characterized in that: The control and protection system of the amplitude and phase corrector also includes a detection circuit; The detection input end of the detection circuit is connected to the first detection interface, the second detection interface, the third detection interface, the fourth detection interface, the fifth detection interface and the sixth detection interface respectively.

4. The control and protection system of the amplitude and phase corrector according to claim 3, characterized in that: The detection circuit at least includes a current signal detection device, a voltage signal detection device and a frequency signal detection device; The detection end of the current signal detection device is respectively connected to the first detection interface, the fourth detection interface, the fifth detection interface and the sixth detection interface; The detection end of the voltage signal detection device is connected to the second detection interface and the third detection interface respectively; The detection end of the frequency signal detection device is connected to the first detection interface and the sixth detection interface respectively.

5. The control and protection system of the amplitude and phase corrector according to claim 3, characterized in that: The control and protection system of the amplitude and phase corrector further comprises a first communication device, and the first communication device is connected to the output end of the detection circuit.

6. The control and protection system of the amplitude and phase corrector according to claim 3, characterized in that: The control and protection system of the amplitude-phase corrector further comprises a second communication device, and the second communication device is connected to the output end of the amplitude-phase corrector circuit.

7. The control and protection system of the amplitude and phase corrector according to claim 3, characterized in that: The control and protection system of the amplitude and phase corrector also includes a cloud storage platform, and the cloud storage platform communicates and interacts with the output end of the detection circuit.

8. The control and protection system of the amplitude and phase corrector according to claim 7, characterized in that: The power transmission line further comprises a disconnection protection circuit, wherein a control end of the disconnection protection circuit is connected to an output end of the detection circuit.

9. The control and protection system for the amplitude and phase corrector according to claim 8, characterized in that: The control end of the disconnect protection circuit is connected to the cloud storage platform.

10. The control and protection system of the amplitude and phase corrector according to claim 7, characterized in that: The control and protection system of the amplitude and phase corrector further comprises an alarm device, wherein the control end of the alarm device is connected to the output end of the detection circuit; The alarm device includes a speaker, an LED light group and a remote communication interaction interface, and the remote communication interaction interface is connected to the cloud storage platform.

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