Control protection system for amplitude and phase corrector

Abstract

This invention discloses a control and protection system for an amplitude-phase corrector, comprising a 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 located on the transmission line. The transmission line is connected in series with the input terminal of the first capacitor circuit. The output terminal of the first capacitor circuit is connected to the input terminals of the second capacitor circuit, the resistor branch, and the lightning protection circuit, respectively. The second capacitor circuit, the resistor branch, and the lightning protection circuit are connected in parallel. This control and protection system for an amplitude-phase corrector, by setting detection interfaces on each circuit branch of the corrector, can monitor its operating status in real time, avoiding current amplitude and phase deviations caused by factors such as line impedance and load changes, thereby ensuring the stability and reliability of the entire power system.

Description

Technical Field

[0001] This invention relates to the field of flexible DC transmission in power systems, and in particular to a control and protection system for an amplitude-phase corrector. Background Technology

[0002] Flexible direct current (DC) transmission technology has been widely used in the power sector due to its advantages such as improving power system stability, providing dynamic reactive power support, and improving power quality. However, because this technology is based on a power electronic system using fully controlled semiconductor devices, it carries the risk of harmonic oscillations when connected to the system, posing a threat to the safe, stable, and reliable operation of the power system.

[0003] To address this risk, both domestic and international approaches currently employ two main methods: software suppression and hardware suppression. Software suppression primarily utilizes impedance reshaping techniques such as adding damping and filtering to the control system, while hardware suppression measures reshape the impedance of the flexible DC transmission system by installing amplitude and phase correctors. As a newly added hardware component in flexible DC transmission systems, the amplitude and phase corrector plays a crucial role in suppressing broadband oscillations.

[0004] 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, promptly detect and handle any potential faults or abnormalities, thereby ensuring the overall stability and reliability of the flexible DC transmission system.

[0005] In existing technologies, the protection of amplitude and phase correctors is mostly based on specific fault types, resulting in limited protection effectiveness. As a protection device for flexible DC transmission systems, how to provide comprehensive protection for amplitude and phase correctors has become a pressing technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0006] This invention provides a control and protection system for an amplitude and phase corrector to solve the problem of limited protection effect of the amplitude and phase corrector, and to achieve comprehensive protection for the amplitude and phase corrector.

[0007] To solve the above-mentioned technical problems, embodiments of the present invention provide a control and protection system for an amplitude-phase corrector, including 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 located on the power transmission line.

[0009] The transmission line is connected in series with the access terminal of the first capacitor circuit, and the output terminal of the first capacitor circuit is connected to the access terminal of the second capacitor circuit, the access terminal of the resistor branch, and the access terminal of the lightning protection circuit, respectively. 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 in order to initially 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 precise 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-phase corrector.

[0014] As one preferred embodiment, the control and protection system of the amplitude-phase corrector further includes a high-voltage side disconnect 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 disconnector 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 disconnector; 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 resistor branch and the grounding point; and the sixth detection interface is located between the second capacitor circuit and the grounding point.

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

[0018] The detection input terminals of the detection circuit are respectively 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.

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

[0020] The detection terminals of the current signal detection device are 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 preferred embodiment, the control and protection system of the amplitude and phase corrector further includes a first communication device, which is connected to the output terminal of the detection circuit.

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

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

[0026] As one preferred embodiment, the transmission line further includes a disconnection protection circuit, the control terminal of which is connected to the output terminal of the detection circuit.

[0027] As one preferred embodiment, the control terminal of the disconnection protection circuit is connected to the cloud storage platform.

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

[0029] The alarm device includes a speaker, LED lights, and a remote communication interface, which is connected to the cloud storage platform.

[0030] Compared with the prior art, the beneficial effects of the embodiments of the present invention are at least one of the following:

[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 operational safety and reliability of the amplitude and phase corrector by setting up capacitor circuit, resistor branch and lightning protection circuit. Attached Figure Description

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

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

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

[0036] Figure label:

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

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all 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 those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

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

[0040] In the description of this invention, it should be noted that, unless otherwise expressly specified and limited, the term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0041] In the description of this invention, it should be noted that, unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this specification is for the purpose of describing specific embodiments only and is not intended to limit the invention. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

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

[0043] To address this risk, both domestic and international approaches currently employ two main methods: software suppression and hardware suppression. Software suppression primarily utilizes impedance reshaping techniques such as adding damping and filtering to the control system, while hardware suppression measures reshape the impedance of the flexible DC transmission system by installing amplitude and phase correctors. As a newly added hardware component in flexible DC transmission systems, the amplitude and phase corrector plays a crucial role in suppressing broadband oscillations.

[0044] 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, promptly detect and handle any potential faults or abnormalities, thereby ensuring the overall stability and reliability of the flexible DC transmission system.

[0045] One embodiment of the present invention provides a control and protection system for an amplitude and phase corrector. For details, please refer to [link to relevant documentation]. Figure 1 , Figure 1 The diagram shown is a circuit diagram of an amplitude-phase corrector system according to one embodiment of the present invention, 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 surge protection circuit D are all located on the transmission line. The transmission line is connected in series with the input terminal of the first capacitor circuit A. In this case, the first capacitor circuit A is used to change the phase difference of the input signal to initially reduce the amplitude and phase error. The output terminal of the first capacitor circuit A is connected to the input terminal of the second capacitor circuit B, the input terminal of the resistor branch C, and the input terminal of the surge protection circuit D, respectively. The second capacitor circuit B, the resistor branch C, and the surge protection circuit D are connected in parallel. The second capacitor circuit B is used to further change the phase response of the transmission line to achieve precise adjustment of the phase of the input signal. The resistor branch C is used for resistor overload protection. The surge protection circuit D is used for internal fault protection of the amplitude and phase corrector.

[0047] It is important to note that during signal transmission, if a resistor overload occurs, resistor branch C will come into play to protect the circuit from damage. However, resistor branch C does not directly participate in signal transmission, but provides protection under specific conditions (such as overload).

[0048] Meanwhile, the lightning protection circuit D does not directly participate in signal transmission. When a fault occurs inside the amplitude and phase corrector or when an abnormal situation such as lightning strikes 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 and phase corrector. At this point, the phase and amplitude of the signal have been optimized, and the amplitude and phase error has been effectively reduced.

[0050] One embodiment of the present invention provides a control and protection system for an amplitude and phase corrector. For details, please refer to [link to relevant documentation]. Figure 2 , Figure 2 This is a circuit diagram of the specific components and detection interfaces of the amplitude and phase corrector system in one embodiment of the present invention, including a high-voltage side disconnect switch 1, a first capacitor 2, a second capacitor 3, a resistor 4, a surge 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 topology of the amplitude-phase corrector. Based on the structure and layout of the amplitude-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.

[0052] The first capacitor circuit A includes a high-voltage side disconnect switch 1 and a first capacitor 2; the second capacitor circuit B includes a second capacitor 3; the resistor branch C includes a resistor 4; and the lightning protection circuit D includes a lightning arrester 5.

[0053] The high-voltage side disconnect 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 disconnect 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 surge 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. The sixth detection interface 11 is located between the second capacitor 3 and the grounding point.

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

[0055] Specifically, the system also includes an alarm device. The control terminal of the alarm device is connected to the output terminal of the detection circuit 3. The alarm device includes a speaker, an LED light group, and a remote communication interface. The remote communication 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] In case of abnormal situations, the sound alarm and optical alarm will automatically generate sound and light, and different alarm levels or types will be indicated by different sounds and colors. The alarm unit communicates with user terminals, cloud storage platforms and other devices via Wi-Fi or Bluetooth. Users can take corresponding measures based on the alarm information, such as tripping the circuit breaker and isolating faulty equipment, to ensure the safe operation of the amplitude and phase corrector.

[0057] One embodiment of the present invention provides a control and protection system for an amplitude and phase corrector. For details, please refer to [link to relevant documentation]. Figure 3 , Figure 3 The diagram shows the control and protection configuration of the amplitude and phase corrector in one embodiment of the present invention.

[0058] In this embodiment, the first end measuring point, the C1 unbalance measuring point, the C2 unbalance measuring point, the surge arrester measuring point, the resistance measuring point, and the tail end measuring point are respectively designated 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 first end measuring point is installed between the amplitude-phase corrector busbar and the high-voltage side disconnector 1; the C1 unbalance measuring point is installed at the first capacitor 2; the C2 unbalance measuring point is installed at the second capacitor 3; the surge arrester measuring point is installed at the tail of the surge arrester 5; the resistance measuring point is installed at the resistance branch C; and the tail end measuring point is installed before the grounding point of the amplitude-phase corrector.

[0060] The detection circuit includes at least 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, voltage signal detection circuit, and frequency signal detection circuit include at least differential protection, overcurrent protection, capacitor imbalance protection, resistor overload protection, reactance overload protection, and detuning alarm.

[0061] Differential protection is used when a fault occurs in the equipment, resulting in a difference between the current flowing into and out of the protected equipment, with the differential current being greater than zero. Differential protection is mainly used to protect transformers from internal short-circuit faults and is the primary protection for transformers.

[0062] Assuming the filtered first-end current is 98A and the last-end current is 95A, the calculated differential current is 3A. If the differential protection threshold is set to 2A, the differential current will exceed the threshold, triggering differential protection. The current value at the surge arrester's measuring point is used to determine if the surge arrester is discharging. Assuming the surge arrester's measuring point current is 5A, if the surge arrester protection threshold is set to 4A, the current will exceed the threshold, triggering differential protection.

[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 imbalance protection is a protective mechanism used to monitor capacitor imbalances in a single-phase capacitor bank caused by blown fuses or damaged capacitors, and to issue an alarm or close a bypass switch. This protection method ensures the normal operation of the capacitor bank and prevents equipment failures caused by capacitor imbalances.

[0065] The capacitor unbalance is calculated using the current values ​​at unbalance measuring points C1 and C2. Assuming the current at unbalance measuring point C1 is 50A and the current at unbalance measuring point C2 is 48A, the calculated unbalance is 4%. If the unbalance protection threshold is set to 3%, the capacitor unbalance protection will be activated if the unbalance exceeds the threshold.

[0066] Calculate the current and power in resistor branch C using the current value at the resistance measuring point. Assuming the current at the resistance measuring point is 80A and the resistance is 10Ω, the calculated power is 6400W. If the resistor overload protection threshold is set to 6000W, the overload protection will be activated if the power exceeds the threshold.

[0067] Reactor overload protection refers to the protective measures taken when the current in a reactor or related circuit exceeds its rated value. This protection ensures the normal operation of the reactor and prevents equipment damage or safety accidents caused by overload. The reactor current is calculated based on the current values ​​at the start and end measuring points. Assuming the start-end current is 100A and the end-end current is 90A, the calculated reactor current is 10A. If the reactor overload protection threshold is set to 8A, the reactor overload protection will be activated when the current exceeds the threshold.

[0068] Detuning alarms are commonly used in power systems. When the system's frequency or phase deviates from a set value, an alarm is triggered. This type of alarm alerts operators to take timely measures to prevent equipment failures or safety accidents caused by system detuning.

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

[0070] Of course, the current and resistance values ​​mentioned above are just examples, and the specific thresholds are determined by the specific working environment.

[0071] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A control and protection system for an amplitude-phase corrector, characterized in that, This includes transmission lines, the first capacitor circuit, the second capacitor circuit, resistor branches, and lightning protection circuits; The first capacitor circuit, the second capacitor circuit, the resistor branch, and the lightning protection circuit are all located on the power transmission line. The transmission line is connected in series with the access terminal of the first capacitor circuit, and the output terminal of the first capacitor circuit is connected to the access terminal of the second capacitor circuit, the access terminal of the resistor branch, and the access terminal of the lightning protection circuit, respectively. 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 in order to initially reduce the amplitude and phase error; The second capacitor circuit is used to further change the phase response of the transmission line to achieve precise 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-phase corrector.

2. The control and protection system for the amplitude and phase corrector as described in claim 1, characterized in that, The control and protection system of the amplitude and phase corrector also includes a high-voltage side disconnect 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 disconnector 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 disconnector; 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 resistor branch and the grounding point; and the sixth detection interface is located between the second capacitor circuit and the grounding point.

3. The control and protection system for the amplitude and phase corrector as described in claim 2, characterized in that, The control and protection system of the amplitude-phase corrector also includes a detection circuit; The detection input terminals of the detection circuit are respectively 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.

4. The control and protection system for the amplitude and phase corrector as described in claim 3, characterized in that, The detection circuit includes at least a current signal detection device, a voltage signal detection device, and a frequency signal detection device; The detection terminals of the current signal detection device are 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 for the amplitude and phase corrector as described in claim 3, characterized in that, The control and protection system of the amplitude and phase corrector also includes a first communication device, which is connected to the output terminal of the detection circuit.

6. The control and protection system for the amplitude and phase corrector as described in claim 3, characterized in that, The control and protection system of the amplitude and phase corrector also includes a second communication device, which is connected to the output terminal of the amplitude and phase corrector circuit.

7. The control and protection system for the amplitude and phase corrector as described in claim 3, characterized in that, The control and protection system of the amplitude and phase corrector also includes a cloud storage platform, which communicates and interacts with the output of the detection circuit.

8. The control and protection system for the amplitude and phase corrector as described in claim 7, characterized in that, The transmission line also includes a disconnection protection circuit, the control terminal of which is connected to the output terminal of the detection circuit.

9. The control and protection system for the amplitude and phase corrector as described in claim 8, characterized in that, The control terminal of the disconnection protection circuit is connected to the cloud storage platform.

10. The control and protection system for the amplitude and phase corrector as described in claim 7, characterized in that, The control and protection system of the amplitude and phase corrector also includes an alarm device, the control terminal of which is connected to the output terminal of the detection circuit. The alarm device includes a speaker, LED lights, and a remote communication interface, which is connected to the cloud storage platform.

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