WO2013007151A1

WO2013007151A1 - Control protection method, device and system for series capacitor device

Info

Publication number: WO2013007151A1
Application number: PCT/CN2012/077820
Authority: WO
Inventors: 武守远; 戴朝波; 李锦屏; 王宇红
Original assignee: 中电普瑞科技有限公司; 中国电力科学研究院
Priority date: 2011-07-11
Filing date: 2012-06-29
Publication date: 2013-01-17
Also published as: BR112014000646A2; CN102244379B; CN102244379A

Abstract

A control protection method, device and system for a series capacitor device.The series capacitor device includes a plurality of common node branches, each branch of the plurality of common node branches being provided thereon with a current transformer used for measuring a current signal on the branch thereof, and the plurality of common node branches including a bypass breaker branch.By receiving the current signals in a plurality of common node branches measured at the same sampling time by each current transformer, identifying whether or not the current signals in the plurality of common node branches satisfy Kirchoff's current law, and determining that the current signals in the plurality of common node branches are not trustable when Kirchoff's current law is not satisfied, thus locking the current protection of the series capacitor device, and enabling the reliability and security of the protection of the series capacitor device to be improved.

Description

Control method, device and system for series capacitor device

The present invention relates to an alternating current transmission technology, and more particularly to a control and protection method, apparatus and system for a series capacitor device. Background technique

The series capacitor compensation of the AC transmission system (hereinafter referred to as: series compensation) technology is to connect the power capacitors in series with the AC transmission line to compensate part of the inductive impedance of the AC transmission line, thereby increasing the line transmission capacity and improving system stability. , saving investment and other purposes. In the large-size, large-capacity transmission system, as the transmission distance increases, its transmission capacity is subject to more and more restrictions, and the series compensation technology is the important factor to solve this problem and improve the transmission capacity of the super/UHV transmission line. One of the means, therefore, has enormous economic value. At present, the series compensation technology has been widely used in power systems in various countries around the world.

The thyristor control series capacitor compensation device (THYRISTOR CONTROLLED SERIES CAPACITORS, TCSC) adjusts the equivalent fundamental impedance of the TCSC by changing the firing angle of the thyristor to achieve dynamic control of the equivalent fundamental impedance, thereby further improving the stability of the power system and increasing The transmission capacity of the transmission line suppresses low-frequency oscillation and sub-synchronous resonance of the power system. When a short-circuit fault occurs in the super/UHV transmission line, the TCSC immediately switches to the thyristor bypass series capacitor mode, which reduces the short-circuit current of the system and improves the stability of the power system.

With the rapid power system, single-unit and power plant capacity, substation capacity, urban and industrial center load and load density continue to increase, and interconnection between power systems, leading to modern large power systems at all levels of the grid The level of short circuit current is constantly increasing. Short-circuit power has become one of the important issues that threaten the safe operation of modern power systems. In addition to changing the grid structure, the series resonant fault current limiter device (FAULT CURRENT LIMITER, FCL) is a new idea and a new way to solve the problem of short-circuit current exceeding the standard. In 2009, the ultra-high voltage fault current limiter device was operated in the 500kV bottle kiln substation of East China Power Grid, and the device is in the stage of promotion and application. Series capacitor devices such as FIXED SERIES COMPENSATION (FSC), TCSC, FCL, etc. all have similar control protection systems. The main control system of the protection system is: measure various fault conditions that are unfavorable to the device during operation, correct action related protection, timely and accurately isolate the fault, ensure the safe and stable operation of the device, and cooperate with the line protection to protect other systems. device. In addition, the control protection system also has functions such as electrical quantity measurement and summary, operation status monitoring, oscillography, human-computer interaction, etc., and realizes bypass breaker (BYPASS CIRCUIT BREAKER, BCB) and isolation knife gate (DISCONNECTOR) in the station. ), grounding knife

(GROUND DISCONNECTOR, GD) Monitoring and control of all critical equipment states, monitoring of critical equipment status by telecontrol equipment within the dispatch house.

Control and protection systems for series capacitor devices such as FSC, TCSC and FCL are mainly used to implement Metal Oxide Varistor (MOV) overcurrent protection, MOV energy protection, MOV temperature protection, MOV imbalance protection, spark gap

(GAP) Protection functions such as self-trigger protection, GAP rejection trigger protection, GAP delay trigger protection, capacitor imbalance protection, and capacitor overload protection. The current signals required to implement the various protection functions above are typically line current, capacitor branch current, capacitor unbalance current, MOV current, and GAP current. Since each untrusted current signal is sent to the control protection system, the current protection associated with it is mis-operated or rejected, thus affecting the reliability and safety of the series capacitor device protection, resulting in unnecessary economic loss. There are many factors that cause the current signal to be unreliable, such as external electromagnetic interference, abnormal operation of the programmable logic device, abnormality of the ANALOG-TO-DIGITAL (A/D) conversion, abnormal operation of the data summary unit, and so on. Summary of the invention

One technique to be solved by the present invention provides a control and protection method, apparatus and system for a series capacitor device to improve the reliability and safety of the protection of the series capacitor device.

In an aspect of an embodiment of the present invention, a control and protection method for a series capacitor device is provided, wherein the series capacitor device includes a plurality of shared node branches, and the plurality of Each of the common node branches is respectively provided with a current transformer, and each current transformer is used for measuring a current signal of a branch node of the shared node, wherein the plurality of common node branches include a side Road breaker branch; the method comprises:

Receiving current signals in the plurality of shared node branches measured by the respective current transformers at the same sampling time;

Identifying whether the current signal in the plurality of shared node branches at the same sampling instant is a full-Hoff law;

If the current signals in the plurality of shared node branches do not satisfy the Kirkhoff current law at the same sampling time, determining that the current signals in the plurality of shared node branches are untrustworthy;

Current protection of the series capacitor device is blocked in response to the unreliable current signal in the plurality of common node branches.

In another aspect of an embodiment of the present invention, a control protection device for a series capacitor device is provided, wherein the series capacitor device includes a plurality of shared node branches, and each of the plurality of shared node branches has a common A current transformer is respectively disposed on the node branch road, and each current transformer is used for measuring a current signal of a branch node of the shared node, wherein the plurality of common node branches include a bypass breaker branch; the control The protection device includes: a receiving unit, configured to receive current signals in the plurality of shared node branches measured by the respective current transformers at the same sampling moment;

a identifying unit, configured to identify whether a current signal in the plurality of shared node branches meets Kirchhoff's current law at the same sampling time;

a determining unit, configured to determine, according to the recognition result of the identifying unit, that the current signals in the plurality of shared node branches do not satisfy the Kirchhoff current law at the same sampling time, and determine the plurality of shared node branches The current signal is not reliable;

And an execution unit, configured to block current protection of the series capacitor device when the determining unit determines that the current signal in the plurality of shared node branches is unreliable.

In still another aspect of an embodiment of the present invention, a control and protection system for a series capacitor device is provided, wherein the series capacitor device includes a plurality of shared node branches, and each of the plurality of shared node branches has a common A current transformer is respectively disposed on the node branch, and each current transformer is used to measure the current signal of the branch node of the shared node. The plurality of shared node branches include a bypass breaker branch; the control protection system includes a platform data acquisition system and a first protection device;

The platform data acquisition system is configured to perform filtering and analog-to-digital conversion processing on current signals in the plurality of shared node branches measured from respective current transformers at the same sampling time, and send the processed current signals Giving a first protection device;

The first protection device is configured to receive a current signal sent by the platform data acquisition system; and identify whether a current signal in the plurality of shared node branches at the same sampling time is a Fullerhoff current law; The current signals in the plurality of shared node branches do not satisfy the Kirchhoff current law, and the current signals in the plurality of shared node branches are determined to be untrustworthy; the current signals in the plurality of shared node branches are not available. In the case of a signal, the current protection of the series capacitor device is blocked.

In the above embodiment of the present invention, a current transformer (CURRENT TRANSFORMER, TA) is respectively disposed on a plurality of shared node branches including the BCB branch in the series capacitor device, so that a plurality of shared node branches in the series capacitor device can be measured. The current signal, and the Kirchhoff current law can be used to accurately determine whether the current signals of the plurality of shared node branches in the series capacitor device are reliable, thereby improving the reliability and safety of the protection of the series capacitor device. DRAWINGS

1 is a flow chart showing an embodiment of a method for controlling and protecting a series capacitor device according to the present invention;

2 is a schematic structural view of an embodiment of a series capacitor device according to the present invention; FIG. 3 is a schematic structural view of another embodiment of a series capacitor device according to the present invention; 5 is a flow chart of another embodiment of a method for controlling and protecting a series capacitor device according to the present invention;

6 is a flow chart showing still another embodiment of a control and protection method for a series capacitor device of the present invention;

7 is a structural diagram showing an embodiment of a control and protection device for a series capacitor device of the present invention; Intention

8 is a schematic structural view of another embodiment of a control and protection device for a series capacitor device according to the present invention;

Figure 9 is a schematic view showing the structure of an embodiment of a control and protection system for a series capacitor device of the present invention;

Figure 10 is a schematic view showing the structure of another embodiment of the control and protection system of the series capacitor device of the present invention;

Figure 11 is a schematic structural view showing still another embodiment of the control and protection system of the series capacitor device of the present invention;

Fig. 12 is a schematic view showing the structure of still another embodiment of the series capacitor device according to the present invention. Specific embodiment

The invention is described more fully hereinafter with reference to the accompanying drawings

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a flow chart showing an embodiment of a control and protection method for a series capacitor device of the present invention. In this embodiment, the series capacitor device includes a plurality of common node branches, and a current transformer is respectively disposed on each of the plurality of shared node branches, and each current transformer is used for each pair The current signal on the branch node of the shared node is measured, and the plurality of common node branches include a bypass breaker branch. As shown in FIG. 1, the control and protection method of the series capacitor device of this embodiment is as follows:

Step 101: Receive current signals in a plurality of common node branches measured by the current transformers at the same sampling time.

Step 102: Identify whether a current signal in a plurality of shared node branches at the same sampling time is a Fullerhoff current law, where the plurality of shared node branches include a series line branch and a branch having a common connection point with the series line branch .

Step 103: If the current signals in the plurality of shared node branches do not satisfy the Kirchhoff current law at the same sampling time, determine that the current signals in the plurality of shared node branches are unreliable.

Step 104, in response to the current signal in the plurality of shared node branches being untrustworthy, the blocking string Current protection of the capacitor unit.

According to the control and protection method of the series capacitor device provided by the above embodiment of the present invention, since a TA is respectively disposed on a plurality of shared node branches including the BCB branch in the series capacitor device, a plurality of shared node branches in the series capacitor device can be measured. The current signal on the road, and the Kirchhoff current law can be used to accurately determine whether the current signals of the plurality of shared node branches in the series capacitor device are reliable, thereby improving the reliability and safety of the protection of the series capacitor device.

According to a particular embodiment of the invention, the series capacitor device may be an FSC, TCSC, FCL, or other similar device. 2 is a schematic structural view of an embodiment of a series capacitor device according to the present invention. In FIG. 2, the series capacitor device is an FSC, specifically including a series line branch, a capacitor bank (C) branch, a MOV branch, a GAP branch, and BCB slip road. 3 is a schematic structural view of another embodiment of the series capacitor device of the present invention. In FIG. 3, the series capacitor device is a TCSC, and specifically includes a series line branch, a capacitor bank branch, a thyristor bypass branch, an MOV branch, The GAP branch and the BCB branch may or may not be provided according to the GAP branch. 4 is a schematic structural view of still another embodiment of the series capacitor device of the present invention. In FIG. 4, the series capacitor device is an FCL, specifically including a series line branch, a capacitor bank branch, a MOV branch, a GAP branch, and a thyristor. The road branch and the BCB branch, the GAP branch and the thyristor bypass branch, may be provided at least one type or both. In the embodiment shown in Figures 2 through 4, a TA is provided for each of the shared node branches including the BCB branch in each series capacitor device. Thus, current signals can be measured on all of the branches of the series line branch, the capacitor bank branch, the MOV branch, the GAP branch, and the BCB branch in each series capacitor device. The capacitor bank shown in Fig. 2, Fig. 3 and Fig. 4 can adopt H-type wiring, double H-type wiring, etc. according to the requirements of capacity, explosion resistance, overvoltage multiple, etc., because the branch current signal involved in the conditions used in the present invention is Since the current signals of the branch nodes are shared, the wiring mode of the capacitor bank and the arrangement of the unbalanced TA are not shown in the figure.

According to another embodiment of the present invention, based on step 102 of the embodiment shown in FIG. 1, if the current signals in the plurality of shared node branches satisfy the Kirchhoff power at the same sampling time The flow law can determine that the current signals in multiple common node branches are believable. At this time, the current protection of the series capacitor device can be performed by the current signal on each branch of the series capacitor device.

Fig. 5 is a flow chart showing another embodiment of the control and protection method of the series capacitor device of the present invention. As shown in FIG. 5, the control protection method of the series capacitor device of this embodiment is as follows:

Step 201: Receive current signals in a plurality of common node branches measured by the current transformers at the same sampling time.

Step 202: Identify whether the current signals in the plurality of shared node branches satisfy the Kirchhoff current law at the same sampling time. If the current signal satisfies the Kirchhoff current law, step 203 is performed. Otherwise, if the current signal does not satisfy the Kirchhoff current law, step 204 is performed.

Step 203: Determine that the current signals in the plurality of shared node branches are trusted. Thereafter, the subsequent 3⁄4⁄2 of the embodiment is not executed.

Step 204: Determine that the current signals in the plurality of shared node branches are not trusted.

Step 205: Determine whether the current signals in the plurality of shared node branches are not trusted at the M consecutive sampling times. Where M is an integer greater than zero.

If less than M consecutive sampling times, the current signals in the plurality of shared node branches are not trusted, that is, the number of consecutive sampling moments in which the current signals in the plurality of shared node branches are not trusted is less than M, and multiple shared nodes are represented. The value of the number of consecutive sampling moments in which the current signal in the branch is untrusted is incremented by one, and step 201 is executed to receive the current signals in the plurality of common node branches measured by the respective current transformers at the next sampling moment. Otherwise, if the current signals in the plurality of shared node branches are not trusted at the M consecutive sampling times, that is, the number of consecutive sampling times in which the current signals in the plurality of shared node branches are untrusted reaches M, and step 206 is performed.

Step 206, blocking current protection of the series capacitor device.

In this embodiment, in the case where the current signal is not credible, in order to avoid the misjudgment caused by the Kirchhoff current law accidentally not met by the individual sampling moments, the Kirchhoff is not satisfied in judging M consecutive sampling moments. After the current law, the delay blocking method of the blocking protection signal is sent. Through this continuous judgment, it is possible to effectively avoid the misjudgment caused by the accidental failure of the current signal at the individual sampling time to satisfy the logical criterion, thereby ensuring the reliability of the judgment.

The following is a detailed analysis of the relationship between the current signals in the node branch of the series capacitor device. Department. The connection point between each branch of the series capacitor device and the series line is called a reference node, and the branch associated with the reference node is called a shared node branch. For example, in the configuration of the series capacitor device embodiment shown in FIG. 2, the connection point A common to the FSC branches and the series line branch 1 is the reference node. The branch associated with reference node A is referred to as a shared node branch. For example, in Figure 2, the series line branch, capacitor bank branch, MOV branch, GAP branch, and BCB branch associated with reference node A will be associated. Called the shared node branch. According to Kirchhoff's current law, the current flowing into the reference node is equal to the current flowing out of the reference node. The direction in which each branch flows into the reference node is a positive direction, including a total of n branches in the series line branch, then 1>=. Or A = 0, where _n is an integer greater than 1, which is the instantaneous value of the branch current signal of the i-th branch in the plurality of common node branches, and is the phasor value of the branch current of the i-th branch, The subscript i indicates the i-th branch.

The current signal ^ of each branch obtained by the current transformer at the sampling time, wherein the subscript T represents the sampling moment, and the subscript i represents the i th branch. The true primary current signal of each branch becomes a secondary current signal and then undergoes electromagnetic interference (ELECTROMAGNETIC

INTERFERENCE, EMI) Filter, signal conditioning unit, A/D conversion unit, photoelectric conversion, etc. The instantaneous sampled data has a certain error compared with the real value directly sampled data. Therefore, take > 0 and close At zero, n is the number of branches

Head. In order to ensure that the current signal is reliable, the maximum absolute error value of the sampled current signal algebra and absolute value that can be obtained by the series capacitor device under different operating conditions can pass a large number of test recording data or field operation data. Refer to the empirical value to get.

It is assumed that the first branch of the plurality of shared node branches is a series line branch, and the nth branch is a BCB branch, and the positive direction of all the shared node current branches is the direction of the flow to the reference node.

1) When the series capacitor device is operating normally, the bypass breaker opens. Tn

2) When a fault occurs in the line fault or a certain fault occurs in the series capacitor device and the BCB is received, the BCB is closed (closed time t=0), according to Kirchhoff's current law,

± ( ≤ , satisfies T.n < δ

3) At t = time, the capacitors of the series capacitor device, MOV, GAP, etc. are attenuated to zero. When the steady state is reached, the BCB branch current signal is equal to the series line branch current.

Under the above three working conditions, the serial value of the sampled value algebra sum of the current signal of each branch node of the series capacitor device is less than or equal to the fixed value and the remaining common node branches except the BCB branch are in each The absolute value of the difference between the absolute value of the sampled value algebraic sum of the current signal and the sampled value of the branch current signal of the BCB is also less than or equal to the fixed value. Therefore, in a specific embodiment of the invention, the condition for identifying whether the current signal meets the condition is:

The operator & is a logical AND operator. The above conditions include two parts, the first condition is δ ₀ if executed to indicate the first condition and the second

The logical value of the condition gives a logical value of 1, which means that both the first condition and the second condition are established, indicating that the current signals on the branches of the plurality of common nodes conform to Kirchhoff's current law. When the inverse value obtained by performing the inverse condition criterion indicating the first condition and the second condition is 0, it means that the first condition and the second condition are not satisfied, and thus the currents of the plurality of shared node branches are represented. There is a case where the signal does not conform to Kirchhoff's current law. In this case, it is necessary to block the current protection of the series capacitor device and check the cause in time.

Since it is not necessary to consider the specific state of the BCB branch when judging by using the first condition and the second condition described above, it is possible to accurately determine whether the plurality of common node branch current signals conform to the Kirchhoff current law at any time. At the same time, the AND operation between the first and second enhances the rigor and reliability of the logic criterion. Since the judgment is made using the double condition, that is, the first condition and the second condition are simultaneously used for the determination, thereby reducing the satisfaction

≤, two or several current signals including the BCB branch current signal simultaneously

The amount of distortion that is untrustworthy and untrustworthy is exactly positive and negative, resulting in the inability to discover the probability of unreliable current signal occurrence.

The logic criterion computes and determines a set of current signal sample data _i ) at each sampling instant.

According to still another embodiment of the present invention, the above-described series capacitor device of the present invention has a control ≤ δ ) & law. E.g

Step 102 of the embodiment shown in FIG. 1 or step 202 of the embodiment shown in FIG. 5 above. In the middle, you can use the logic criterion ( ) & ( < δ ) to judge the current letter.

Whether the number complies with Kirchhoff's current law.

According to another embodiment of the present invention, in order to further improve the reliability and safety of the control and protection method of the series capacitor device, the two series of protection devices having the same redundancy and the same function may be used to respectively perform the control of the series capacitor device of the present invention. Protection method. Two of the protection devices independently receive current signals in the plurality of common node branches measured by the respective current transformers at the same sampling time, and independently block each other when determining that the current signals of the plurality of common node branches are unreliable Current protection for series capacitor devices.

Two mutually redundant protection devices can respectively perform various embodiments of the control and protection method of the above series capacitor device of the present invention. Figure 6 is a flow chart showing still another embodiment of the control and protection method of the series capacitor device of the present invention, wherein the two protection devices can independently perform the following steps 301-304:

Step 301: Receive current signals in the plurality of common node branches measured by the current transformers at the same sampling time.

Step 302: Identify whether the current signals in the plurality of shared node branches satisfy the Kirchhoff current law at the same sampling time.

Step 303: If the current signals in the plurality of shared node branches do not satisfy the Kirchhoff current law at the same sampling time, determining that the current signals in the plurality of shared node branches are unreliable.

Step 304: Block current protection of the series capacitor device when the current signals in the plurality of shared node branches are unreliable.

Fig. 7 is a schematic view showing the construction of an embodiment of a control and protection device for a series capacitor device of the present invention. The control protection device of this embodiment can be used to implement the corresponding operation of the control and protection method of the above series capacitor device of the present invention. In this embodiment, the series capacitor device includes a plurality of shared node branches, and each of the plurality of shared node branches is respectively provided with a current transformer, and each current transformer is used for the same The current signal on the common node branch is measured, and the plurality of common node branches include the bypass breaker branch. The control protection device of this embodiment includes:

The receiving unit 701 is configured to receive each current transformer measured at the same sampling time Current signals in multiple common node branches.

The identifying unit 702 is configured to identify whether the current signals in the plurality of shared node branches satisfy the Kirchhoff current law at the same sampling time.

The determining unit 703 is configured to determine, according to the recognition result of the identifying unit 702, that the current signals in the plurality of shared node branches do not satisfy the Kirchhoff current law at the same sampling time, and determine that the current signals in the plurality of shared node branches are not trusted .

The executing unit 704 is configured to block current protection of the series capacitor device when the determining unit 703 determines that the current signals in the plurality of shared node branches are unreliable.

According to the control protection device of the series capacitor device provided by the above embodiment of the present invention, since a TA is respectively disposed on a plurality of shared node branches including the BCB branch in the series capacitor device, a plurality of shared node branches in the series capacitor device can be measured. The current signal on the road, and the Kirchhoff current law can be used to accurately determine whether the current signals of the plurality of shared node branches in the series capacitor device are reliable, thereby improving the reliability and safety of the protection of the series capacitor device.

According to a particular embodiment of the invention, the series capacitor device may be an FSC, TCSC, FCL or other similar device. In FIG. 2, the series capacitor device is FSC; in FIG. 3, the series capacitor device is TCSC, wherein there may be a GAP branch or a GAP branch as needed; in FIG. 4, FCL, where GAP can be set as needed And at least one of the thyristor bypass branches.

According to another embodiment of the present invention, the determining unit 703 in the embodiment shown in FIG. 7 can further satisfy the Kirchhoff current signal in the plurality of shared node branches at the same sampling time according to the recognition result of the identifying unit 702. In the current law, it is determined that the current signals in the branches of multiple common nodes are believable.

FIG. 8 is a schematic structural view of another embodiment of a control and protection device for a series capacitor device according to the present invention. The control protection device of this embodiment can be used to implement the function of the control and protection method of the series capacitor device in the above-described embodiment of Fig. 5 of the present invention. Referring to FIG. 8, the control protection device of the embodiment further includes a determining unit 801, wherein: the determining unit 801 is configured to determine, in the determining unit 703, currents in the plurality of shared node branches, as compared with the embodiment shown in FIG. When the signal is not trusted, it is judged whether there are multiple common node branches in M consecutive sampling moments. The current signal is not trusted, and M is an integer preset to be greater than zero. If the current signals in the plurality of shared node branches are not trusted at less than M consecutive sampling times, the value indicating the continuous sampling time is cumulatively increased by one, and the receiving unit 701 receives the current transformers respectively measured at the next sampling time. Current signals in a plurality of shared node branches; if the current signals in the plurality of shared node branches are not trusted at the M consecutive sampling instants, the indicating execution unit 704 blocks current protection of the series capacitor device.

According to still another embodiment of the present invention, in the embodiment of the control protection device of the series capacitor device of the present invention, the identification unit 702 may specifically determine the current signal by using a logic criterion (δ) indicating the first condition and the second condition. Yes

Does it comply with Kirchhoff's current law. For example, the identification unit in the embodiment shown in Figures 7 and 8

In 702, the logic criterion ( δ ) can be used to judge the electricity.

Whether the stream signal conforms to Kirchhoff's current law. When the logical value obtained by the logic criterion is 1, it means that both the first condition and the second condition are satisfied, and the current signals representing the branches of the plurality of shared nodes are in accordance with the Kirchhoff current law. However, when the logic value obtained by the logic rule of Xunhai is 0, it means that the first condition and the second condition are not established, so that the current signals on the branches of the plurality of common nodes do not conform to the Kirchhoff current law. Happening. Since it is not necessary to consider the specific state of the BCB branch when judging by using the first condition and the second condition, it is possible to accurately determine the branch currents of the plurality of common nodes at any time. Whether the signal conforms to Kirchhoff's current law. At the same time, the AND operation between the first condition and the second condition reinforces the rigor and reliability of the logic criterion. Since the judgment is made using the double condition, that is, the first condition and the second condition are simultaneously used for the determination, thereby reducing the satisfaction

< time, two or several current signals including the BCB branch current signal simultaneously

Fig. 9 is a block diagram showing the construction of an embodiment of a control and protection system for a series capacitor device of the present invention. The control protection system of the series capacitor device of this embodiment can be used to implement the control and protection method of the above series capacitor device of the present invention. As shown in FIG. 9, the control protection system includes a platform data acquisition system 901 and a first protection device 902. At the same time, the series capacitor device comprises a plurality of shared node branches, and each of the plurality of shared node branches is respectively provided with a current transformer, and each current transformer is respectively used for the current on the branch node of the shared node The signal is measured and the multiple common node branches include bypass breaker branches. Its + :

The platform data acquisition system 901 is configured to receive and process current signals in a plurality of shared node branches of the plurality of shared node legs in the series capacitor device at the same sampling time. The platform data acquisition system 901 performs filtering, A/D conversion, and the like on the received current signal by using an EMI filter, a signal conditioning unit, and an A/D conversion unit, and processes the processed current signal through a corresponding optical path. The first protection device 902 is delivered to the control room.

The first protection device 902 is configured to receive a current signal sent by the platform data collection system 901; identify whether the current signal in the plurality of shared node branches meets the Kirchhoff current law at the same sampling time; if multiple common nodes at the same sampling time The current signal in the branch is not full of Erkhov's current law, and it is determined that the current signals in the plurality of common node branches are unreliable; when the current signals in the plurality of common node branches are not reliable, the current protection of the series capacitor device is blocked.

A control and protection system for a series capacitor device according to the above embodiment of the present invention, A TA is respectively disposed on a plurality of shared node branches including the BCB branch in the series capacitor device, so that current signals of a plurality of shared node branches in the series capacitor device can be measured, and can be accurately determined by using Kirchhoff current law Whether the current signals of the plurality of shared node branches in the series capacitor device are reliable, thereby improving the reliability and safety of the protection of the series capacitor device.

According to a specific embodiment of the invention, the series capacitor device may be FSC, TCSC, FCL, or other similar device. In Figure 2, the series capacitor device is FSC; in Figure 3, the series capacitor device is TCSC, where there may be a GAP branch or a GAP branch as needed; in Figure 4, the series capacitor device is FCL, where At least one of a GAP and a thyristor bypass branch may be provided.

Fig. 10 is a structural schematic view showing another embodiment of the control and protection system of the series capacitor device of the present invention. In this embodiment, the control protection system includes a platform data acquisition system 901, a first protection device 902, and an operating device 903, wherein:

The current signal is first transmitted to the data summarizing unit 911 in the first protection device 902 via the optical path in the form of an optical signal. The data summary unit 911 first converts the optical signal into an electrical signal, and parses the sampled data therefrom, and then presses the sampled data. The pre-agreed data format is sent to each control unit 912 and protection unit 913.

In practical engineering applications, the optical path and platform data acquisition system 901 can be directly exposed to the outdoors, and the data summary unit 911 can be placed within the ground control protection. Since the data summary unit 911 is the data source of the ground control protection system, its working performance largely determines the operation status of the entire control protection system. Therefore, the data summary unit 911 is required to have high-speed and stable data processing capability and a certain degree. Error detection and error correction, strong anti-interference characteristics, and can provide rich status information for its own working conditions.

The first protection device 902 identifies, according to the current signal provided by the platform data acquisition system 901, whether the current signals of the plurality of shared node branches satisfy the Kirchhoff current law; if the current signal does not satisfy the Kirchhoff current law, the determination is determined. The current signals in the common node branches are not trusted; when the current signals in the plurality of shared node branches are not trusted, the current protection of the series capacitor device is blocked by the control unit 912.

The operating device 903 is configured to be controlled according to the protection unit 912 in the first protection device 902 System, perform the corresponding circuit breaker, knife gate and other operations.

In accordance with an embodiment of the present invention, the associated identification and determination operations involved in the first protection device 902 can be performed within the data summary unit 911 or the protection unit 913 in the first protection device 902. If the above operation is performed in the data summary unit 911, the identification operation and the determination operation are the last logical operation before the current signal is transmitted to the protection unit 913. If the operation for identification and determination is performed within the protection unit 913, the current signal is transmitted to the first logical operation after the protection unit 913.

In the control and protection system of the series capacitor device of the embodiments of the present invention, the first protection device 902 can be specifically realized by the specific embodiments of the control protection device of the series capacitor device of the present invention. For example, in this embodiment, the first protection device 902 specifically employs the embodiment shown in Figure 7 of the present invention.

Figure 11 is a block diagram showing another embodiment of the control and protection system of the series capacitor device of the present invention. In order to further improve the reliability of the control and protection method of the series capacitor device, two protection devices each having the same redundancy, the same function and structure, including the first protection device 902 and the second protection device 922, respectively, may be used to perform the present invention. Control and protection method for series capacitor devices. The first protection device 902 and the second protection device 922 respectively receive the current signals in the plurality of common node branches measured by the respective current transformers at the same sampling time, and determine the current signals of the plurality of shared node branches. When not authentic, the current protection of the series capacitor device is independently blocked. The two mutually redundant first protection devices 902 and second protection devices 922 can be specifically implemented by the invention of the control device of the series capacitor device. The embodiment shown in FIG. The series capacitor device of the embodiment shown in Fig. 12 is taken as an example.

Referring to FIG. 11, compared with the embodiment shown in FIG. 10, the embodiment has a data acquisition with the first protection device 902 and the platform separately from the first protection device 902, the operation device 903, and the platform data acquisition system 901. The second protection device 922 and the platform data acquisition system 921, which are mutually redundant in the system 901, have the same functions as mutually redundant devices. The secondary side of the measurement TA has two channels through which measurement data is transmitted to the platform data acquisition systems 901 and 921, respectively. The platform data acquisition systems 901 and 921 respectively transmit the current signals processed by filtering, A/D conversion, etc. to the first protection device 902 and the second protection device 922. First A protection device 902 and a second protection device 922 independently receive current signals in a plurality of common node branches measured by the respective current transformers at the same sampling time, and determine that the current signals of the plurality of shared node branches are untrustworthy The current protection of the series capacitor device is individually blocked.

The embodiment of the present invention will be specifically described below by taking the series capacitor device as an example of FSC.

Fig. 12 is a schematic view showing the structure of the series capacitor device according to the present invention when it is FSC. The FSC includes a series capacitor bank, two metal oxide voltage limiters MOV1 and MOV2, and a damping device. , spark gap GAP, bypass breaker BCB and the current transformer TA1~TA7 installed on the branch and the line branch of each key equipment. The series capacitors are single H-type wiring.

In Fig. 12, node A is taken as the reference node, and the number of each branch is the same as the number of each branch current transformer, and the direction of the incoming node A is the positive direction. The sampling signals of the series line branch current, the capacitor group branch current, the capacitor bridge branch current, the MOV1 branch current, the MOV2 branch current, the GAP branch current, and the BCB branch current are sequentially corresponding to the two sets of acquisition systems. Two sets of mining

W ", ie .Al ~ .Ai and .Bl ~ .Bl.

The function of determining whether the current signal is authentic in this embodiment can be implemented in the data summary unit 911 in the first protection device 902 and the second protection device 922, respectively. It can also be implemented in the protection unit 913 in the first protection device 902 and the second protection device 922, respectively.

Let ^: for the node A corresponding to the algebraic sum of all the branch current sample values, then the present embodiment determines the current signals of the branches of each shared node, namely: i _T , i _T2 , i _TA , i _{T 5} , i ^l ]T .6

The condition that I T.7 is credible is (| _£ | <& - 1 || <s') _B δ, which can be obtained by a large number of test recording data or field operation data with reference to empirical values. In order to avoid misjudgment caused by accidental failure of the current sampling signal at the time of individual sampling, the parameter Μ=5 of the time delay blocking in this embodiment.

In the first protection device 902, ¹ KCL.A ― ^l T.Al + ^l T.A2 + ^l T.A4 + ^l T.A5 + ^l T.A6 + ^l T.Al is calculated, and it is judged whether the condition A is satisfied:

(|^ _c J≤ &(|^ _C . - _r . ₇ |_| _r . ₇ | ≤^) ; Also calculated in the second protection device 922 ¹ KCL.B― ^l T.Bl + ^l T.B2 + ^l TB + ^l T.B5 + ^l T.B6 + ^l T.Bl, and judge whether the condition is satisfied:

< ^l KCL.B― ¹ Τ.ΒΊ ― \ ¹ Τ.ΒΊ ≤ . There should be three judgments:

1) If the current signal is full in both protection devices, it means that the signals received by both protection devices are reliable.

2) If, in one of the protection devices, the current signals of the plurality of shared node branches are not full for 5 consecutive sampling times, it indicates that one or more of the current signals of the plurality of shared node branches received by the protection device The current signal is unreliable, and the control unit 912 of the protection device blocks the current protection, and timely checks the cause of the unreliable current signal according to the recorded data. If the damage occurs to a component in the platform data acquisition system or protection device, the protection system can be removed and the damaged component replaced. The other current signal satisfies the corresponding condition of the protection device to operate normally.

3) If, in the two protection devices, the measurement signals of the multiple shared node branches do not satisfy the above corresponding conditions for 5 consecutive sampling times, it indicates that the two protection nodes received by the two redundant protection devices are mutually shared. The current signals on the road are not trusted, and the control unit 912 in the two protection devices that are redundant with each other blocks the current protection.

It should be pointed out that since the third case has a low probability of occurrence, it is still possible to control and protect each series capacitor device in the case where the current signal is unreliable and the system has a fault.

The description of the present invention has been presented for purposes of illustration and description. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiment is described in order to more clearly illustrate the principles and practical applications of the present invention, and one of ordinary skill in the art can understand the present invention to design various embodiments with various modifications that are suitable for a particular use.

Claims

&Wo' J wants

A control and protection method for a series capacitor device, wherein the series capacitor device includes a plurality of shared node branches, and each of the plurality of shared node branches is provided with a current a transformer, each of which is configured to measure a current signal of a branch node of the shared node thereof, wherein the plurality of common node branches include a bypass breaker branch; the method includes:

The method according to claim 1, wherein the identifying whether the current signal in the plurality of shared node branches satisfies the Kirchhoff current law at the same sampling time comprises:

Identifying, at the same sampling time T, whether the current signals in the plurality of shared node branches satisfy the first condition έ ≤ and the second condition < δ, where η is the number of the plurality of shared node branches, η is an integer greater than 1, and is a current signal on the i-th branch of the plurality of shared node branches at the sampling time. The subscript i is an integer greater than zero and not greater than n, and is a value greater than zero by default. ;

If the current signals in the plurality of shared node branches satisfy the first condition and the second condition at the same sampling time T, it is considered that the current signals in the plurality of shared node branches satisfy the Kirchhoff at the same sampling time T Current law;

Otherwise, if the first condition and the second condition are met when the current signals in the plurality of shared node branches are different at the same sampling time T, it is considered that the current signals in the plurality of shared node branches are not satisfied at the same sampling time T Kirchhoff's current law.

The method according to claim 2, wherein if the current signals in the plurality of shared node branches satisfy the Kirchhoff current law at the same sampling time, determining the plurality of shared node branches The current signal is reliable.

The method according to any one of claims 1 to 3, further comprising: after determining that the current signal in the plurality of shared node branches is untrustworthy, further comprising:

Determining whether the current signals in the plurality of shared node branches are not trusted at the M consecutive sampling moments, and the M value is an integer preset to be greater than zero;

Rescuing the current protection of the series capacitor device in response to the current signal in the plurality of shared node branches being untrusted comprises: when the current signals in the plurality of shared node branches are not trusted at the M consecutive sampling instants , blocking current protection of the series capacitor device.

The method according to any one of claims 1 to 3, wherein the method is respectively performed by two mutually redundant and functionally identical protection devices, wherein the protection devices independently receive the respective current transformers The current signals in the plurality of shared node branches measured at the same sampling instant, and JL^, when determining that the current signals are unreliable, independently block current protection of the series capacitor device.

The method according to any one of claims 1 to 3, wherein the series capacitor device comprises a fixed series capacitor compensation device, a thyristor control series capacitor compensation device or a series resonance type fault current limiter device.

7. A control protection device for a series capacitor device, the series capacitor device comprising a plurality of common node branches, each of the plurality of shared node branches being provided with a current transformer, respectively The current transformers are respectively used for measuring the current signals of the branch nodes on the common node, and the plurality of common node branches include bypass circuit breaker branches; the control protection device includes:

a receiving unit, configured to receive current signals in the plurality of shared node branches measured by the respective current transformers at the same sampling moment;

a determining unit, configured to determine, according to the recognition result of the identifying unit, that the current signal in the plurality of shared node branches does not satisfy the Kirchhoff current law at the same sampling time Current signals in multiple common node branches are not trusted;

The device according to claim 7, wherein the identification unit specifically identifies whether the current signal in the plurality of shared node branches simultaneously satisfies the first condition 3⁄4 ≤ and the second condition at the same sampling time T ≤ , where n is the number of the plurality of shared node branches, and η is an integer greater than 1, and is a current signal at the i-th branch of the plurality of shared node branches at the sampling time The subscript i is an integer greater than zero and not greater than n, and is a value preset to be greater than zero; if the current signals in the plurality of shared node branches satisfy the first and second strips at the same sampling time T, It is considered that the current signals in the plurality of shared node branches satisfy the Kirchhoff current law at the same sampling time T; otherwise, if the current signals in the plurality of shared node branches are different at the same sampling time T, the first condition is satisfied. And the second condition, it is considered that the current signal in the plurality of common node branches at the same sampling time T does not satisfy the Kirchhoff current law.

The device according to claim 8, wherein the determining unit is further configured to: according to the recognition result of the identifying unit, if the current signal in the plurality of shared node branches meets the Kiel at the same sampling time The Hoff current law determines that the current signals in the plurality of shared node branches are trusted.

The device according to any one of claims 7 to 9, further comprising: a determining unit, configured to determine whether the current signal in the plurality of shared node branches is untrustworthy at the M consecutive sampling moments, The M value is an integer preset to be greater than zero. If the current signals in the plurality of shared node branches are not trusted at the M consecutive sampling moments, the execution unit is instructed to block the current protection of the series capacitor device.

The apparatus according to any one of claims 7 to 9, characterized in that the series capacitor device comprises a fixed series capacitor compensation device, a thyristor control series capacitor compensation device or a series resonance type fault current limiter device.

12. A control and protection system for a series capacitor device, wherein: the series capacitor device comprises a plurality of common node branches, and each of the plurality of shared node branches is provided with a current Transformer, each current transformer is used to The current signal of the shared node branch is measured, and the plurality of shared node branches include a bypass breaker branch; the control protection system includes a platform data acquisition system and a first protection device;

The system according to claim 12, wherein the first protection device is specifically a control protection device of the series capacitor device according to any one of claims 7 to 10.

The system according to claim 12, wherein the series capacitor device comprises a fixed series capacitor compensation device, a thyristor control series capacitor compensation device or a series resonance type fault current limiter device.

The system according to claim 14, wherein the thyristor control series capacitor compensation device includes a spark gap branch.

The system according to claim 14, wherein the series resonance type fault current limiter device includes at least one of a spark gap branch and a thyristor bypass branch.

The system according to claim 12, further comprising a second protection device redundant with the first protection device, configured to receive a current signal sent by the platform data acquisition system; Whether the current signal in the plurality of shared node branches satisfies the Kirchhoff current law at the sampling time; if the current signals in the plurality of shared node branches do not satisfy the Kirchhoff current law at the same sampling time, The current signals in the plurality of shared node branches are not trusted; when the current signals in the plurality of shared node branches are not trusted, Blocking current protection of the series capacitor device;

The first protection device and the second protection device each independently receive a current signal sent by the platform data acquisition system, and independently block the series capacitor when the current signals of the plurality of shared node branches are unreliable Current protection of the device.