CN210092867U - Converter station auxiliary device and converter station - Google Patents
Converter station auxiliary device and converter station Download PDFInfo
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- CN210092867U CN210092867U CN201920845955.5U CN201920845955U CN210092867U CN 210092867 U CN210092867 U CN 210092867U CN 201920845955 U CN201920845955 U CN 201920845955U CN 210092867 U CN210092867 U CN 210092867U
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Abstract
The application relates to a converter station auxiliary device and a converter station, which comprise a control protection device, a first branch circuit and a second branch circuit, wherein the first branch circuit and the second branch circuit are connected in parallel; the first end of the first branch circuit and the second end of the second branch circuit after being connected in parallel are connected with a neutral point of a converter station connecting transformer, and the second end of the first branch circuit is grounded; the first branch comprises a first circuit breaker; the second branch comprises a first load; when a single-pole ground fault occurs, fault current forms a fault loop through the first load. Due to the fact that the first load is large, the short-circuit current flowing in the single-pole ground fault is small, and the condition that the converter station can continuously operate for a period of time under the condition of the single-pole ground fault can be met, so that power supply reliability of the system is improved. The control protection device is used for outputting a closing signal to the first circuit breaker when the fault current of the second branch circuit is detected; the first circuit breaker is switched to a closed state after receiving the closing signal, so that the short-circuit current is increased, and the protection device is conveniently controlled to position the fault branch and the fault position.
Description
Technical Field
The application relates to the technical field of electrical automation, in particular to a converter station auxiliary device and a converter station.
Background
In recent years, the development of the flexible direct current technology becomes an important direction of the development of the power grid technology, related scientific research and demonstration projects of flexible direct current projects have been developed in a power distribution network, direct current will become a development trend, and particularly in the field of power transformation and power distribution, the power grid will be developed into an alternating current and direct current coexisting state in the future. An important field in the flexible direct current technology of the power distribution network is the design of an electric main loop of a flexible direct current converter station which is suitable for the characteristics of a distribution network. The electric main circuit can meet the functional requirements of the mode conversion of the input and the cut of the electric circuit in normal operation. The fault point can be quickly cut off in the fault process, and the electrical equipment is protected from being damaged.
In the implementation process, the inventor finds that at least the following problems exist in the conventional technology: in the traditional method for positioning the fault position, the fault current is small, and the fault positioning difficulty is large.
SUMMERY OF THE UTILITY MODEL
In view of the above, it is necessary to provide a converter station auxiliary device and a converter station that can increase a fault current.
In order to achieve the above object, in one aspect, the embodiment of the present invention provides a converter station auxiliary device, which includes a control protection device, and a first branch and a second branch connected in parallel;
the first end of the first branch circuit and the second end of the second branch circuit after being connected in parallel are connected with a neutral point of a converter station connecting transformer, and the second end of the first branch circuit is grounded; the first branch comprises a first circuit breaker; the second branch comprises a first load;
the control protection device is used for transmitting a closing signal to the first circuit breaker when the fault current of the second branch circuit is detected; when the first circuit breaker receives a closing signal, the first circuit breaker is switched to a closed state.
In one embodiment, the system further comprises a second load; the second load is connected in series with the first branch.
In one embodiment, the first load is a first resistor, and the second load is a second resistor; the resistance value of the first resistor is larger than that of the second resistor.
In one embodiment, the first resistor is a resistor with a resistance greater than 1000 Ω and less than 10000 Ω, and the second resistor is a resistor with a resistance greater than 100 Ω and less than 1000 Ω.
In one embodiment, the system further comprises a first current transformer; the first current transformer is connected between the second end of the first branch and the second branch which are connected in parallel and the ground in series.
In one embodiment, the lightning arrester further comprises a lightning arrester; one end of the lightning arrester is connected with the neutral point, and the other end of the lightning arrester is grounded.
On the other hand, the embodiment of the utility model provides a converter station still includes converter valve, coupling transformer and the converter station auxiliary device of any one above-mentioned;
the high-voltage side of the connecting transformer is used for connecting an alternating current power supply, and the low-voltage side of the connecting transformer is connected with a converter valve; an upper bridge arm of the converter valve is used for connecting a direct current positive pole circuit, and a lower bridge arm of the converter valve is used for connecting a direct current negative pole circuit.
In one embodiment, the system further comprises a station power branch; the first end of the station power branch is connected with the high-voltage side of the transformer, and the second end of the station power branch is used for connecting an external circuit;
the station power branch comprises a disconnecting device and a station transformer which are connected in series; one end of the disconnecting device is connected with the high-voltage side of the station transformer, the other end of the disconnecting device is connected with the high-voltage side of the station transformer, and the low-voltage side of the station transformer is connected with an external circuit.
In one embodiment, the breaking device comprises a second circuit breaker and a disconnector; the second circuit breaker and the disconnector are connected in series in the station power branch.
In one embodiment, the station power branch further comprises a second current transformer; one end of the second current transformer is connected with the high-voltage side of the station transformer, and the other end of the second current transformer is connected with the cut-off device.
One of the above technical solutions has the following advantages and beneficial effects:
the converter station auxiliary device comprises a control protection device, a first branch and a second branch, wherein the first branch and the second branch are connected in parallel; the first end of the first branch circuit and the second end of the second branch circuit after being connected in parallel are connected with a neutral point of a converter station connecting transformer, and the second end of the first branch circuit is grounded; the first branch comprises a first circuit breaker; the second branch comprises a first load; when a single-pole ground fault occurs, fault current forms a fault loop through the first load. Due to the fact that the first load is large, the short-circuit current flowing in the single-pole ground fault is small, and the condition that the converter station can continuously operate for a period of time under the condition of the single-pole ground fault can be met, so that power supply reliability of the system is improved. The control protection device is used for outputting a closing signal to the first circuit breaker when the fault current of the second branch circuit is detected; the first circuit breaker is switched to a closed state after receiving the closing signal. Because the short-circuit current is small, the control protection device is not favorable for judging the fault position, and therefore after the fault occurs, if the system does not need to continuously operate, the first breaker can be automatically closed to short-circuit the first resistor, so that the short-circuit current is increased, and the control protection device is convenient to position the fault branch and the fault position.
Drawings
The foregoing and other objects, features and advantages of the application will be apparent from the following more particular description of preferred embodiments of the application, as illustrated in the accompanying drawings. Like reference numerals refer to like parts throughout the drawings, and the drawings are not intended to be drawn to scale in actual dimensions, emphasis instead being placed upon illustrating the subject matter of the present application.
Fig. 1 is a block diagram of a first schematic circuit configuration of an auxiliary device of a converter station according to an embodiment;
fig. 2 is a block diagram of a second schematic circuit configuration of an auxiliary device of the converter station in an embodiment;
fig. 3 is a block diagram of a third schematic circuit configuration of an auxiliary device of the converter station in an embodiment;
fig. 4 is a block diagram of a fourth schematic circuit configuration of an auxiliary device of the converter station in an embodiment;
fig. 5 is a block diagram of a first schematic circuit configuration of a converter station according to an embodiment;
fig. 6 is a block diagram of a second schematic circuit configuration of a converter station according to an embodiment;
FIG. 7 is a block diagram of a schematic circuit configuration of a cut-off device in one embodiment;
fig. 8 is a block diagram of a schematic circuit configuration of the station power branch in one embodiment.
Detailed Description
To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present application are shown in the drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element and be integral therewith, or intervening elements may also be present. The terms "high pressure side", "low pressure side", "one end", "the other end" and the like are used herein for illustrative purposes only.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
In one embodiment, as shown in fig. 1, a converter station auxiliary device comprises a control protection device 10, and a first branch 20 and a second branch 30 connected in parallel;
the first end of the first branch 20 and the second branch 30 after being connected in parallel is connected with a neutral point of a converter station connecting transformer, and the second end is grounded; the first branch 20 comprises a first circuit breaker CB 1; the second branch 30 comprises a first load 301;
the control protection device 10 is used for transmitting a closing signal to the first circuit breaker CB1 when the fault current of the second branch circuit 30 is detected; when receiving a closing signal, the first circuit breaker CB1 is switched to a closed state.
The control protection device 10 is a secondary device of the converter station, and has functions of monitoring, checking abnormality of line work of the converter station, and controlling devices in the converter station. The neutral point is a common point at which the head ends (or tail ends) of the three-phase coils are connected together when the connection transformer is star-connected. The first load 301 may be any resistive component.
The first branch 20 is used to increase the current in the loop and the second branch 30 is used to limit the current in the loop. The first branch 20 comprises a first circuit breaker CB1 and the second branch 30 comprises a first load 301, the first circuit breaker CB1 being in an open state when the lines of the converter station are working properly. When a single-pole ground fault occurs, the fault current passes through the first load to form a fault loop, and the resistance value of the first load 301 is large, so that the current limiting effect is achieved, and the short-circuit current passing through the single-pole ground fault is small, so that the condition that the converter station can continuously operate for a period of time under the condition of the single-pole ground fault can be met. The control protection device 10 may detect the fault current of the second branch circuit 30, and specifically, may detect the fault current through any technical means in the art, and when the fault current of the second branch circuit 30 is detected, may control to close the first circuit breaker CB1, so that the first load 301 is shorted, thereby achieving the effect of increasing the current in the loop. In a specific example, the first circuit breaker CB1 may be a relay, one end of a coil of the relay is grounded, the other end of the coil is connected to the control protection device 10, a moving contact and a fixed contact of the relay are connected to the first branch, when the control protection device 10 detects a fault current of the second branch 30, a high level signal is output to the coil, and the moving contact and the fixed contact are contacted by a magnetic force, so that the first branch is turned on, the second branch is shorted, an effect of increasing the current is achieved, and the control protection device 10 is conveniently controlled to locate and troubleshoot the fault branch and the fault position.
The converter station auxiliary device comprises a control protection device, a first branch and a second branch which are connected in parallel; the first end of the first branch circuit and the second end of the second branch circuit after being connected in parallel are connected with a neutral point of a converter station connecting transformer, and the second end of the first branch circuit is grounded; the first branch comprises a first circuit breaker; the second branch comprises a first load; when a single-pole ground fault occurs, fault current forms a fault loop through the first load. Due to the fact that the first load is large, the short-circuit current flowing in the single-pole ground fault is small, and the condition that the converter station can continuously operate for a period of time under the condition of the single-pole ground fault can be met, so that power supply reliability of the system is improved. The control protection device is used for outputting a closing signal to the first circuit breaker when the fault current of the second branch circuit is detected; the first circuit breaker is switched to a closed state after receiving the closing signal. Because the short-circuit current is small, the control protection device is not favorable for judging the fault position, and therefore after the fault occurs, if the system does not need to continuously operate, the first breaker can be automatically closed to short-circuit the first resistor, so that the short-circuit current is increased, and the control protection device is convenient to position the fault branch and the fault position.
In one embodiment, as shown in fig. 2, a second load 203 is further included; the second load is connected in series in the first branch 20.
The second load 203 may be any component having a resistance value; the second load is connected in series in the first branch. The second load 203 is connected in series to the first branch 20, and when the control protection device 10 detects a fault current, the resistance value of the equivalent resistor connected in parallel can be reduced when the first branch 20 is in a conducting state, so that the current of the control loop is not too large under the condition of increasing the current, and the safety of components is ensured.
In one embodiment, the first load 301 is a first resistor, and the second load 203 is a second resistor; the resistance value of the first resistor is larger than that of the second resistor.
Specifically, a first resistor is used as the first load, and a second resistor is used as the second load. The first resistor is used for limiting current in a loop, and the second resistor is connected with the first resistor in parallel under the condition of a single-pole ground fault, so that the parallel equivalent resistance value is reduced, and the effect of increasing the current is achieved.
As a preferred embodiment, the resistance of the first resistor is greater than 1000 Ω and less than 10000 Ω, and the resistance of the second resistor is greater than 100 Ω and less than 1000 Ω. Considering the actual voltage of the converter station, the resistance range of the first resistor for limiting the current is larger than 1000 Ω and smaller than 10000 Ω, so that a more reasonable current limiting effect can be achieved. The resistance range of the second resistor is larger than 100 omega and smaller than 1000 omega, and when the fault detection is carried out, the increased current is more reasonable due to the equivalent resistance value after the parallel connection, and the fault detection and positioning effect is easy.
In one embodiment, as shown in fig. 3, a first current transformer CT1 is also included; the first current transformer CT1 is connected in series between the second end of the first branch 20 and the second branch 30 after being connected in parallel and the ground.
The current transformer 40 is used for detecting a current value of the loop, and can provide the current value of the current loop for a worker, so that the current transformer is used for relay protection, measurement and metering.
In one embodiment, as shown in fig. 4, further comprises a lightning arrester 50; one end of the arrester 50 is connected to the neutral point, and the other end is grounded. The arrester 50 functions as a voltage protection in the converter station auxiliary equipment.
In one embodiment, as shown in fig. 5, a converter station is provided comprising converter valves 60, a coupling transformer 70 and converter station auxiliary equipment 80 as described in any of the above;
the high-voltage side of the coupling transformer 70 is used for connecting an alternating current power supply, and the low-voltage side is connected with a converter valve; the upper arm of the converter valve 60 is used to connect a direct current positive line, and the lower arm of the converter valve 60 is used to connect a direct current negative line.
Wherein the converter valve 60 is used for converting alternating current into direct current.
Specifically, the ac power source outputs an initial ac current to the coupling transformer 70; the coupling transformer 70 converts the initial alternating current into a present alternating current of a corresponding voltage class and transmits the present alternating current to the converter valves; the converter valve 60 converts the current ac current into a positive dc current and a negative dc current, and outputs the positive dc current to the dc positive line through the upper bridge arm and the negative dc current to the dc negative line through the lower bridge arm.
The control and protection device 10 is used to detect whether a single-pole ground fault occurs in the circuit, and further, when the single-pole ground fault occurs, the second branch 30 generates a fault current. When the control protection device 10 detects the fault current of the second branch circuit 30, a closing signal is output to the first circuit breaker CB 1.
The converter station described above, comprising a converter valve, a coupling transformer and a converter station auxiliary device as described in any of the above; the high-voltage side of the connecting transformer is used for connecting an alternating current power supply, and the low-voltage side of the connecting transformer is connected with a converter valve; an upper bridge arm of the converter valve is used for connecting a direct-current positive pole circuit, and a lower bridge arm of the converter valve is used for connecting a direct-current negative pole circuit; the control protection device is used for outputting a closing signal to the first circuit breaker when the fault current of the second branch circuit is detected; the first circuit breaker is switched to a closed state after receiving the closing signal. Because the short-circuit current is small, the control protection device is not favorable for judging the fault position, and therefore after the fault occurs, if the system does not need to continuously operate, the first breaker can be automatically closed, the short-circuit current is increased, and the control protection device is convenient to position the fault branch and the fault position.
In one embodiment, as shown in fig. 6, further comprises a station power branch 90; a first end of the station power branch is connected with a first end of the coupling transformer 70, and a second end of the station power branch 90 is used for connecting an external line;
the station power branch 90 includes a disconnecting device 901 and a station transformer 903 connected in series; one end of the disconnecting device 901 is connected to the high-voltage side of the station transformer, the other end is connected to the high-voltage side of the station transformer, and the low-voltage side of the station transformer is connected to an external line.
The station power branch 90 is used for supplying power to converter station equipment, the disconnecting device 901 is used for isolating the station power branch from a main line, and the station transformer 903 is used for regulating an input voltage.
Specifically, the station power branch 90 includes a disconnecting device 901 and a station transformer 903, and one end of the disconnecting device 901 is connected to the high-voltage side of the station transformer 903 and the other end is connected to the high-voltage side of the coupling transformer 70. When the disconnecting device 901 is closed, the station transformer 903 starts operating and outputs the voltage converted by the station transformer to the outside. When the disconnecting device 901 is disconnected, the station transformer 903 stops operating.
The converter station comprises the station power utilization branch, so that the converter station provided by the application does not need an external access power supply, and the cost caused by laying of an external power supply line is reduced.
In one embodiment, as shown in fig. 7, the breaking device 901 comprises a second circuit breaker CB2 and a disconnector DS 1; the second circuit breaker CB2 and the disconnector DS1 are connected in series in the station electrical branch.
Specifically, the disconnecting device 901 comprises a second circuit breaker CB2 and a disconnecting switch DS1, wherein the second circuit breaker CB2 is used for disconnecting a line, the disconnecting switch DS1 is used for pulling a line contact open, and the disconnection of the line can be effectively ensured through the second circuit breaker CB2 and the disconnecting switch DS 1.
In one embodiment, as shown in fig. 8, the station electrical branch 90 further includes a second current transformer CT 2; one end of the second current transformer CT2 is connected to the high-voltage side of the station transformer, and the other end is connected to the disconnecting device 901.
The second current transformer CT2 is used to detect the current value of the loop, and can provide the current value of the current loop for the staff for relay protection, measurement and metering. In one specific example, a ground knife ES1 is provided and connected to the high-voltage side of station transformer 903 to provide power to station transformer 903, and the low-voltage side of station transformer 903 outputs 380 vac to provide power to the total station equipment. The second circuit breaker CB2 and the disconnecting switch DS1 are used for switching in and switching out the electric branch of the operation station. The ground knife ES1 is used for closing during maintenance.
The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above examples only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the utility model. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present invention should be subject to the appended claims.
Claims (10)
1. The converter station auxiliary device is characterized by comprising a control protection device, a first branch and a second branch which are connected in parallel;
the first end of the first branch circuit and the second end of the second branch circuit after being connected in parallel are connected with a neutral point of a converter station connecting transformer, and the second end of the first branch circuit is grounded; the first branch comprises a first circuit breaker; the second branch comprises a first load;
the control protection device is used for transmitting a closing signal to the first circuit breaker when the fault current of the second branch circuit is detected; and when receiving the closing signal, the first circuit breaker is switched to a closed state.
2. A converter station auxiliary device according to claim 1, characterized in that it further comprises a second load;
the second load is connected in series with the first branch.
3. A converter station auxiliary device according to claim 2, characterized in that said first load is a first resistor and said second load is a second resistor; the resistance value of the first resistor is larger than that of the second resistor.
4. A converter station auxiliary device according to claim 3, characterized in that said first resistor is a resistor having a resistance of more than 1000 Ω and less than 10000 Ω, and said second resistor is a resistor having a resistance of more than 100 Ω and less than 1000 Ω.
5. The converter station auxiliary device according to claim 1, further comprising a first current transformer;
the first current transformer is connected between a second end of the first branch and a second end of the second branch which are connected in parallel and the ground in series.
6. A converter station auxiliary device according to claim 1, characterized in that it further comprises a lightning arrester;
one end of the lightning arrester is connected with the neutral point, and the other end of the lightning arrester is grounded.
7. A converter station, characterized by comprising converter valves, coupling transformers and converter station auxiliary devices according to any of claims 1 to 6;
the high-voltage side of the connecting transformer is used for connecting an alternating current power supply, and the low-voltage side of the connecting transformer is connected with the converter valve; the upper bridge arm of the converter valve is used for connecting a direct current positive pole circuit, and the lower bridge arm of the converter valve is used for connecting a direct current negative pole circuit.
8. The converter station according to claim 7, further comprising a station power branch; the first end of the station power utilization branch is connected with the high-voltage side of the connecting transformer, and the second end of the station power utilization branch is used for connecting an external line;
the station power utilization branch comprises a disconnecting device and a station transformer which are connected in series; one end of the switching-off device is connected with the high-voltage side of the station transformer, the other end of the switching-off device is connected with the high-voltage side of the station transformer, and the low-voltage side of the station transformer is connected with the external circuit.
9. A converter station according to claim 8, characterized in that said breaking means comprise a second circuit breaker and a disconnector;
the second circuit breaker and the disconnecting switch are connected in series in the station power branch.
10. The converter station according to claim 8, characterized in that said station power branch further comprises a second current transformer;
one end of the current transformer is connected with the high-voltage side of the station transformer, and the other end of the current transformer is connected with the on-off device.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201920845955.5U CN210092867U (en) | 2019-06-05 | 2019-06-05 | Converter station auxiliary device and converter station |
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| CN201920845955.5U CN210092867U (en) | 2019-06-05 | 2019-06-05 | Converter station auxiliary device and converter station |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110247376A (en) * | 2019-06-05 | 2019-09-17 | 中国能源建设集团广东省电力设计研究院有限公司 | Converter station auxiliary device, method and converter station |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110247376A (en) * | 2019-06-05 | 2019-09-17 | 中国能源建设集团广东省电力设计研究院有限公司 | Converter station auxiliary device, method and converter station |
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