CN110649585A - Energy discharge device and high-voltage power transmission system - Google Patents
Energy discharge device and high-voltage power transmission system Download PDFInfo
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- CN110649585A CN110649585A CN201910937302.4A CN201910937302A CN110649585A CN 110649585 A CN110649585 A CN 110649585A CN 201910937302 A CN201910937302 A CN 201910937302A CN 110649585 A CN110649585 A CN 110649585A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
- H02H9/04—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage
- H02H9/041—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage using a short-circuiting device
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/36—Arrangements for transfer of electric power between ac networks via a high-tension dc link
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]
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Abstract
The invention provides an energy leakage device and a high-voltage power transmission system, and relates to the field of power systems. The embodiment of the invention can absorb the energy transmitted to the VSC in time when the voltage of the VSC is overhigh, thereby avoiding the fault of the VSC. The energy leakage device provided by the embodiment of the invention is applied to a high-voltage direct-current transmission system, wherein the first end of the energy leakage device is connected with the high-voltage end of a Voltage Source Converter (VSC), and the second end of the energy leakage device is connected with the grounding end of the Voltage Source Converter (VSC); the energy leakage device comprises a fixed energy leakage element and a control module; wherein: the fixed energy leakage element and the control module are connected in series between the first end of the energy leakage device and the second end of the energy leakage device; a fixed energy dissipating element comprising a plurality of energy dissipating units connected in series between a first end and a second end of the fixed energy dissipating element; and the control module is used for conducting the first end and the second end of the control module when detecting that the voltage carried by the VSC is greater than the threshold voltage. The invention is applied to electric power leakage.
Description
This application claims priority from a chinese patent application filed on 12.7.2019 under the name "a let-down device" under the name of 201910631564.8 from the national intellectual property office, the entire contents of which are incorporated herein by reference.
Technical Field
The invention relates to the field of power systems, in particular to an energy leakage device and a high-voltage power transmission system.
Background
High-voltage power transmission is a mode of transmitting the voltage output by a generator after boosting the voltage through a transformer for a power plant. The reason for transmitting power in this way is that in the case of power transmitted simultaneously, the higher the voltage, the smaller the current, so that high-voltage transmission can reduce the current during power transmission, thereby reducing the heat loss due to the current and reducing the material cost for long-distance transmission.
With the popularization of high-voltage transmission technology, the application of VSC (voltage source converter) is also becoming more and more widespread. In order to guarantee that when the alternating current-direct current system trouble appears, can take protective measure to the VSC in several milliseconds, often utilize equipment such as direct current circuit breaker to protect the VSC among the prior art. However, the dc circuit breaker is expensive. Therefore, how to protect VSCs and reduce equipment cost is an urgent problem to be solved.
Disclosure of Invention
The invention provides an energy leakage device and a high-voltage transmission system, which can absorb redundant energy transmitted to a VSC in time when the voltage of the VSC is too high, so that the fault of the VSC is avoided.
In order to achieve the above purpose, the embodiment of the invention adopts the following technical scheme:
in a first aspect, an embodiment of the present invention provides an energy discharging device, which is applied to a high-voltage direct-current power transmission system, wherein a first end of the energy discharging device is used for connecting a high-voltage end of a voltage source converter VSC, and a second end of the energy discharging device is used for connecting a ground end of the voltage source converter VSC; the energy leakage device comprises a fixed energy leakage element and a control module; wherein: the fixed energy-discharging element and the control module are connected in series between the first end of the energy-discharging device and the second end of the energy-discharging device; the first end of the control module is connected with the first end of the energy leakage device, and the second end of the control module is connected with the first end of the fixed energy leakage element; the second end of the fixed energy-discharging element is connected with the first end of the energy-discharging device; or the first end of the fixed energy-discharging element is connected with the first end of the energy-discharging device, and the second end of the fixed energy-discharging element is connected with the first end of the control module; the second end of the control module is connected with the second end of the energy leakage device; the fixed energy discharging element comprises a plurality of energy dissipation units connected in series between a first end and a second end of the fixed energy discharging element; the control module is configured to conduct a first end and a second end of the control module when it is detected that the voltage carried by the VSC is greater than a threshold voltage.
Optionally, the plurality of energy dissipation units included in the fixed energy discharging element are nonlinear resistance elements; the energy discharge device further comprises a controlled energy discharge element; the controlled energy discharge element comprises a plurality of energy dissipation units connected in series between a first end and a second end of the controlled energy discharge element; the plurality of energy dissipation units included in the controlled energy discharge element are nonlinear resistance elements; the first end of the controlled energy leakage element is connected with the first end of the control module, and the second end of the controlled energy leakage element is connected with the second end of the control module.
Optionally, the control module specifically includes a first fast switching unit and a first mechanical breaker; wherein the first fast switching unit and the first mechanical breaker are connected in parallel between the first end and the second end of the control module; the first mechanical breaker is used for converting current and switching off direct current when the protection module is withdrawn; the first fast switch unit specifically includes: the quick closing mechanical switch controls one of a trigger gap switch or a power electronic switch.
Optionally, the power electronic switch specifically includes: the semi-control type power electronic device or the full-control type power electronic device, and a dynamic and stable state voltage-sharing element, a reactor and a series mechanical switch for auxiliary current interruption which are matched with the semi-control type power electronic device or the full-control type power electronic device.
Optionally, the energy discharging device further comprises a protection module; the first end of the protection module is connected with the first end of the energy leakage device, and the second end of the protection module is connected with the second end of the energy leakage device; the protection module is used for conducting a path between the first end and the second end of the protection module when the temperature of the energy leakage device is greater than a threshold temperature or the energy absorbed by the energy leakage device reaches an energy threshold.
Optionally, the protection module specifically includes a second fast switching unit and a second mechanical breaker; wherein the second fast switching unit and the second mechanical breaker are connected in parallel between the first end and the second end of the protection module; the second fast switch unit specifically includes: the quick switch-on mechanical switch is one of a controllable trigger gap switch or a power electronic switch.
Optionally, the power electronic switch specifically includes but is not limited to: the semi-control type power electronic device or the full-control type power electronic device, and a dynamic and stable state voltage-sharing element, a reactor and a series mechanical switch for auxiliary current interruption which are matched with the semi-control type power electronic device or the full-control type power electronic device.
Optionally, the energy discharging device further includes: a refrigeration module; the refrigeration module is used for reducing the ambient temperature of an energy dissipation unit in the energy leakage device.
Optionally, the control module is specifically configured to conduct the first end and the second end of the control module when it is detected that an average value of capacitance voltages of sub-modules in a plurality of sub-modules included in the VSC is greater than a threshold voltage.
Optionally, the protection module is further configured to conduct the first end and the second end of the protection module when it is detected that the voltage carried by the VSC is greater than the threshold voltage and the control module fails to operate.
In a second aspect, the invention also includes a high voltage power transmission system comprising the energy discharge apparatus provided in the first aspect.
According to the energy leakage device and the high-voltage transmission system provided by the embodiment of the invention, the fixed energy leakage element and the control module in the energy leakage device are connected in series between the high-voltage end and the high-voltage end of the VSC, and when the voltage borne by the VSC is overhigh, the control module is controlled to be conducted, so that the redundant energy transmitted to the VSC can be released through the fixed energy leakage element, and the problem that the voltage borne by the VSC is continuously increased and further damage is caused is avoided. The energy leakage device provided by the embodiment of the invention can protect VSC, and has the characteristics of simple structure and low cost.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below.
Fig. 1 is a schematic structural diagram of a dc power transmission system according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of an energy discharging device according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of a VSC according to an embodiment of the present invention;
fig. 4 is a second schematic structural diagram of an energy discharging device according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of a control module according to an embodiment of the present invention;
fig. 6 is a second schematic structural diagram of a control module according to a second embodiment of the present invention;
fig. 7 is a third schematic structural diagram of a control module according to an embodiment of the present invention;
fig. 8 is a third schematic structural diagram of an energy discharging device according to an embodiment of the present invention;
FIG. 9 is a fourth schematic structural diagram of an energy discharging device according to an embodiment of the present invention;
fig. 10 is a schematic structural diagram of a protection module according to an embodiment of the present invention;
fig. 11 is a second schematic structural diagram of a protection module according to a second embodiment of the present invention;
fig. 12 is a third schematic structural diagram of a protection module according to an embodiment of the present invention;
fig. 13 is a schematic diagram illustrating an energy absorbing process of the energy discharging device 10 during a receiving end ac fault according to the embodiment of the present invention;
fig. 14 is a schematic diagram of an energy absorbing process of the energy discharging device 10 when a fault occurs in a converter station according to an embodiment of the present invention.
Detailed Description
Embodiments of the present invention will be described below with reference to the accompanying drawings.
Firstly, the inventive concept of the energy leakage device provided by the embodiment of the invention is introduced:
no matter what the prior art usually adopts the protection elements with fixed and unchangeable parameters and performance to realize the energy leakage of the overvoltage, or the energy leakage through the controllable lightning arrester, the normal operation of the power grid is ensured by timely releasing the overvoltage in the power grid from the viewpoint of releasing the overvoltage in the power grid. For example, in the prior art, it is common to control the discharge of the arrester when the voltage of the grid exceeds the rated transmission voltage by m% (m is a constant value) to ensure the normal operation of the grid.
In the present invention, considering that different electrical devices have different tolerance levels to overvoltage, if the leakage capacity is controlled only by the ratio of the current overvoltage to the rated transmission voltage, the electrical device with poor tolerance may be damaged.
Furthermore, the embodiment of the invention provides an energy leakage device and a high-voltage transmission system, which are used for protecting the VSC in the transmission network and avoiding the problem of damage caused by overlarge load voltage of the VSC.
Based on the above inventive concept, an embodiment of the present invention provides an energy discharging apparatus, as shown in fig. 1, an energy discharging apparatus 10 provided in the embodiment of the present invention is applied to a high-voltage direct current (HVDC) system, and specifically, may be an extra-high voltage dc transmission system. Fig. 1 is a schematic diagram of an extra-high voltage transmission system, in which a power transmission terminal converts ac power into dc power through two LCCs (line commutated converters) LCC _1 and LCC _2 to input the dc power to a power grid (for example, in the example of fig. 1, the power grid adopts 800kV standard). Then, at the receiving end, the LCC may be used to convert the dc power to ac power (as shown in fig. 1, part of LCC _ 3), or the VSC may be used to achieve the effect of converting the dc power to ac power.
It should be noted that fig. 1 is only a schematic structural diagram of an extra-high voltage power transmission system in an application scenario of the energy discharging apparatus 10 provided in the embodiment of the present invention. In specific implementation, the energy leakage device provided by the invention can also be applied to other scenes, and the invention is not limited to the energy leakage device.
Specifically, in the embodiment of the present invention, a first terminal of the energy discharging device 10 is connected to a high-voltage terminal of the VSC, and a second terminal of the energy discharging device 10 is connected to a ground terminal of the voltage source converter VSC.
As shown in fig. 1, the energy discharging device 10 according to the embodiment of the present invention is connected to the transmission grid in parallel with the VSC between the dc bus (i.e., the energy discharging device 10 is connected to the high-voltage end of the VSC) and the ground (i.e., the energy discharging device 10 is connected to the ground end of the VSC).
The fixed energy discharging element 101 and the control module 102 are connected in series between a first end of the energy discharging device 10 and a second end of the energy discharging device 10.
Wherein a first end of the control module 102 is connected to a first end of the energy discharging device 10, and a second end of the control module 102 is connected to a first end of the fixed energy discharging element 101; the second end of the fixed energy-discharging element 101 is connected with the first end of the energy-discharging device 10;
or, a first end of the fixed energy-discharging element 101 is connected to a first end of the energy-discharging device 10, and a second end of the fixed energy-discharging element 101 is connected to a first end of the control module 102; a second end of the control module 102 is connected to a second end of the discharging device 10.
Specifically, as shown in fig. 2, a first end of the fixed energy discharging element 101 is connected to the high-voltage end of the VSC, and a second end of the fixed energy discharging element 101 is connected to a first end of the control module 102. A second terminal of the control module 102 is connected to ground.
The fixed energy discharging element 101 may specifically be composed of a plurality of energy dissipating units connected in series between a first end and a second end of the fixed energy discharging element 101.
Wherein, the energy dissipation unit is a nonlinear resistance element. In particular, the energy dissipation unit may be a zinc oxide sheet.
In addition, the energy dissipation units constituting the fixed energy discharging element 101 may include a ring type or a cake type. The outer surface of the fixed energy release element 101 can be coated with an insulating coating, or can be coated with silicon rubber or ceramic.
It is considered that a large amount of heat is generated when energy is consumed by an energy discharging element such as an energy dissipating unit. In order to ensure that the energy leakage element can operate in a low-temperature state for a long time. In one implementation manner, in an embodiment of the present invention, the energy discharging apparatus 10 may further include: a cooling module for reducing the ambient temperature of the energy dissipating unit in the energy discharge device 10. Specifically, the refrigeration module can specifically adopt an air cooling system and a water cooling system.
And the control module 102 is configured to conduct the first end and the second end of the control module when it is detected that the voltage carried by the VSC is greater than the threshold voltage.
According to the energy leakage device provided by the embodiment of the invention, the fixed energy leakage element and the control module in the energy leakage device are connected in series between the high-voltage end and the grounding end of the VSC, when the voltage borne by the VSC is overhigh, the control module is controlled to be conducted, so that the redundant power transmitted to the VSC can be released through the fixed energy leakage element, and the problem that the voltage borne by the VSC is continuously increased and further the VSC is damaged is avoided.
Fig. 3 shows a schematic diagram of a VSC structure. Wherein one VSC comprises a plurality of VSC converter valves. One converter valve comprises a plurality of sub-modules (such as SM1 and SM2 … … SMn in the figure) connected in series, and the structure of the sub-modules is specifically shown in FIG. 3.
In one implementation, in order to ensure the accuracy of the detected voltage, in an embodiment of the present invention, the control module 102 is specifically configured to conduct the first terminal and the second terminal of the control module 102 when detecting that an average value of capacitance voltages of each of a plurality of sub-modules included in the VSC is greater than a threshold voltage.
In addition, as shown in fig. 4, the discharging device 10 further includes a controlled discharging element 103.
Wherein the controlled energy discharging element 103 comprises a plurality of energy dissipating units connected in series between a first end and a second end of the controlled energy discharging element 103.
Wherein, the energy dissipation unit is a nonlinear resistance element. In particular, the energy dissipation unit may be a zinc oxide sheet.
In addition, the energy dissipation unit of the controlled energy discharge element 103 may comprise a ring type or a pie type. The outer surface of the controlled energy release element 103 can be coated with an insulating coating or can be coated with only a silicone rubber jacket or a ceramic jacket.
Wherein, a first end of the controlled energy release element 103 is connected to a first end of the control module 102, and a second end of the controlled energy release element 103 is connected to a second end of the control module 102.
In the embodiment of the present invention, when the system normally operates, two ends of the control module 102 are in an off state, and at this time, the fixed energy leakage element 101 and the controllable energy leakage element 103 are connected in series to function to bear the power frequency voltage of the system. When the lightning invasion wave overvoltage occurs, the fixed energy-discharging element 101 and the controllable energy-discharging element 103 are connected in series to limit the voltage jointly, so that the energy-discharging device 10 has a certain lightning protection function.
In addition, in one implementation, as shown in fig. 5, the control module 102, in particular, includes a first fast switching unit 1021 and a first mechanical breaker 1022; wherein the first fast switching unit 1021 is connected in parallel with the first mechanical breaker 1022 between the first and second ends of the control module 102; the first mechanical breaker 1022 is used for commutation and breaks the dc current when the protection module 104 described below is withdrawn.
The first fast switch unit 1021 specifically includes: the quick switch-on mechanical switch is one of a controllable trigger gap switch or a power electronic switch. Power electronic switch specifically includes: semi-controlled power electronic devices and fully-controlled power electronic devices. And a dynamic and stable state voltage-sharing element, a reactor and a series mechanical switch for auxiliary current interruption matched with the voltage-sharing element.
For example, as shown in fig. 6, the control module 102 may specifically include a quick-closing mechanical switch 1021a and a mechanical breaker 1022 a. As shown in fig. 7, the control module 102 may specifically include a semi-controlled power electronic device 1021b and a mechanical breaker 1022 b.
The power electronic switch branch in the embodiment of the present invention may adopt, but is not limited to: thyristor, etc. (the semi-controlled power electronic devices need to be configured with corresponding forced turn-off loops to ensure the reliable exit of the controllable part), or can be fully-controlled power electronic devices such as IGBT, IGCT, etc. The gap may be, but is not limited to, an air gap, a sulfur hexafluoride gap. The quick closing mechanical switch can adopt but is not limited to a sulfur hexafluoride switch of an electromagnetic repulsion mechanism or a vacuum switch of the electromagnetic repulsion mechanism. Which may include, but is not limited to, other resistive, capacitive, inductive, etc. devices.
In the embodiment of the invention, the control module 102 is formed by connecting the quick switch and the mechanical breaker in parallel, so that when the control module 102 needs to be conducted, the current can be firstly conducted due to the high closing speed of the quick switch, and the overvoltage can be timely discharged. After the conventional mechanical breaker is also turned on, the fast switch can be turned off, and the commutation is realized. After the discharging action is finished, the function of cutting off the direct current is realized by utilizing the breaking capacity of the conventional circuit breaker again.
In one implementation, as shown in fig. 8 and 9, the energy discharging apparatus 10 provided in the embodiment of the present invention further includes a protection module 104.
Wherein, a first end of the protection module 104 is connected to a first end of the energy discharging device 10, and a second end of the protection module 104 is connected to a second end of the energy discharging device 10;
and the protection module 104 is used for conducting a path between the first end and the second end of the protection module 104 when the temperature of the energy discharging device 10 is greater than the threshold temperature or the energy absorbed by the energy discharging device 10 reaches the energy threshold.
In one implementation, the protection module 104 is further configured to conduct the first end and the second end of the protection module 104 when it is detected that the voltage carried by the VSC is greater than the threshold voltage and the control module 102 fails to operate.
In the embodiment of the present invention, in order to avoid the damage of the energy discharging device 10, when the energy discharging device 10 is out of limit, that is, the energy absorbed by the energy discharging device 10 reaches the energy threshold, and the temperature of the energy discharging device 10 is greater than the threshold temperature, and other few extreme conditions occur, the energy discharging device 10 is bypassed by conducting the two ends of the protection module 104, so as to protect the energy discharging device 10.
In one implementation mode, the problem that a conventional mechanical circuit breaker is slow in closing speed, and a fast switch has the problem that a plurality of fractures are complex to operate when the fast switch is turned off is considered. As shown in fig. 10, the protection module 104 in the embodiment of the present invention specifically includes a second fast switch unit 1041 and a second mechanical breaker 1042.
The second fast switching unit 1041 and the second mechanical breaker 1042 are connected in parallel between the first end and the second end of the protection module 104.
The second fast switch unit 1041 specifically includes: the quick switch-on mechanical switch is one of a controllable trigger gap switch or a power electronic switch. Power electronic switch specifically includes: the semi-controlled power electronic device, the fully controlled power electronic device, and the dynamic and steady state voltage-sharing element, the reactor and the auxiliary current-cutoff serial mechanical switch which are matched with the semi-controlled power electronic device and the fully controlled power electronic device.
For example, as shown in fig. 11, the protection module 104 may specifically include a quick-closing mechanical switch 1041a and a mechanical breaker 1042 a. As shown in fig. 12, the protection module 104 may specifically include a semi-controlled power electronic device 1041b and a mechanical breaker 1042 b.
Considering that when the protection module 104 is turned on, the current di/dt flowing through the protection module 104 is relatively large, in the embodiment of the present invention, a reactance may be connected in series to the protection module 104 to limit the current flowing through the protection branch. Other devices such as resistors, capacitors, inductors, etc. may also be included in the protection module 104.
The power electronic switch branch in the embodiment of the present invention may adopt, but is not limited to: thyristor, etc. (the semi-controlled power electronic devices need to be configured with corresponding forced turn-off loops to ensure the reliable exit of the controllable part), or can be fully-controlled power electronic devices such as IGBT, IGCT, etc. The gap may be, but is not limited to, an air gap, a sulfur hexafluoride gap, or other gas gap. The quick closing mechanical switch can adopt but is not limited to a sulfur hexafluoride switch of an electromagnetic repulsion mechanism or a vacuum switch of the electromagnetic repulsion mechanism. Which may include, but is not limited to, other resistive, capacitive, inductive, etc. devices.
In the embodiment of the invention, the protection module 104 is formed by connecting the quick switch and the mechanical breaker in parallel, so that when the protection module 104 needs to be conducted, the current can be firstly conducted due to the high closing speed of the quick switch, and the overvoltage can be timely discharged. After the conventional mechanical breaker is also turned on, the fast switch can be turned off, and the commutation is realized. After the discharging action is finished, the function of cutting off the direct current is realized by utilizing the breaking capacity of the conventional circuit breaker again.
In addition, in the embodiment of the present invention, the energy discharging device 10 further includes a refrigeration module. A cooling module for reducing the ambient temperature of the energy dissipating unit in the energy discharge device 10. Specifically, the energy dissipation device includes a fixed energy leakage element 101 and an energy dissipation unit included in a controlled energy leakage element 103.
According to the energy leakage device provided by the embodiment of the invention, the fixed energy leakage element and the control module in the energy leakage device are connected in series between the high-voltage end and the grounding end of the VSC, and when the voltage borne by the VSC is overhigh, the control module is controlled to be conducted, so that the voltage on the high-voltage end of the VSC can be released through the fixed energy leakage element, and the problem that the voltage borne by the VSC is continuously increased and further damaged is avoided.
The following describes the use of the energy discharge device 10 provided by the embodiment of the present invention with reference to the following examples:
illustratively, when the energy discharging device 10 provided by the embodiment of the invention is applied to an extra-high voltage direct current transmission system. The operation of the energy discharging device 10 is as follows:
and S201, under the condition that the power transmission system is normal, the control module 102 is disconnected, and the protection module 104 is disconnected. The system works normally.
S202, when the receiving end alternating current system fault occurs, the voltage of the direct current bus starts to rise, and the voltage of the sub-modules in the VSC starts to rise. Assume that the current dc transmission system is a 400kV system.
And S203, when the average value of the capacitor voltage on each submodule reaches an action constant value (in an implementation mode, the action constant value can be set to be 2.6kV), the direct current control protector sends an action command.
And S204, after receiving the action command, the energy leakage device 10 conducts the control module 102, and further limits the voltage at the input end of the VSC to be below a preset range by using the fixed energy leakage element 101, so as to ensure that the VSC is not damaged.
And S205, when the fault of the receiving end alternating current system is clear, the direct current control protector sends an action instruction to disconnect the control module 102. Further, the energy release device 10 and the VSC equipment both safely pass the failure period.
S206, after the control module 102 is conducted in the step S204, if the absorbed energy of the fixed energy leakage element 101 exceeds the limit value, the direct current control energy-saving device sends an energy out-of-limit signal to the energy leakage device 10. The energy dump device 10 latches the VSC upon receiving the energy violation signal and controls the protection module 104 to conduct. The overvoltage is then released by the protection module 104, so that the bleeder device 10, the VSC equipment, both safely pass the fault period. Fig. 13 is a schematic diagram illustrating an energy absorption process of the energy discharging device 10 when a receiving end ac fails.
In one implementation, the energy discharging apparatus 10 provided in the embodiment of the present invention further achieves a certain fault tolerance by enabling the protection module 104 to conduct the first end and the second end of the protection module 104 when detecting that the voltage carried by the VSC is greater than the threshold voltage and the control module 102 fails. Specifically, another work flow of the energy discharging device 10 is described below, which specifically includes:
s301, if the power transmission system is normal, the control module 102 is turned off and the protection module 104 is turned off. The system works normally.
And S302, when the receiving-end alternating current system fails, the voltage of the direct current bus starts to rise, and the voltage of the sub-module in the VSC starts to rise. Assume that the current dc transmission system is a 400kV system.
And S303, when the average value of the capacitor voltage on each submodule reaches an action constant value (in an implementation mode, the action constant value can be set to be 2.6kV), the direct current control protector sends an action command.
And S304, after receiving the action command, the energy leakage device 10 conducts the control module 102. At this time, if the control module 102 fails to operate, it cannot be conducted.
And S305, after the control module 102 refuses to operate, locking the low end of the energy leakage device at the VSC, and limiting the bus voltage to be lower than 665kV by the energy leakage device 10 under the common voltage limit of the fixed energy leakage element 101 and the controllable energy leakage element 103.
And S306, tripping the VSC alternating current circuit breaker to break the connection between the VSC and the alternating current system.
S307, the direct current control energy-saving device sends an energy out-of-limit signal to the energy discharging device 10. The energy dump device 10 latches the VSC upon receiving the energy violation signal and controls the protection module 104 to conduct. The overvoltage is then released by the protection module 104, so that the bleeder device 10, the VSC equipment, both safely pass the fault period.
In addition, the energy leakage device 10 provided by the embodiment of the present invention can also be used in the case of a fault in the converter station. Specifically, the operation of the energy discharging device 10 is as follows:
and S401, when the station internal fault occurs in the receiving end converter station, locking the receiving end converter station in the operating VSC, and sending an operation command to the energy leakage device 10.
S402, after receiving the operation command, the energy discharging device 10 turns on the control module 102 to limit the dc bus voltage to be less than 540 kV.
And S403, tripping the VSC alternating current circuit breaker to break the connection between the VSC and the alternating current system.
S404, after the fault is ended, the control module 102 is disconnected, and the equipment is recovered to be in normal operation.
In addition, after the control module 102 is turned on, if the absorbed energy of the fixed energy leakage element 101 exceeds the limit value, the direct current control energy-saving device sends an energy out-of-limit signal to the energy leakage device 10. The energy dump device 10 latches the VSC upon receiving the energy violation signal and controls the protection module 104 to conduct. The overvoltage is then released by the protection module 104, so that the bleeder device 10, the VSC equipment, both safely pass the fault period. Illustratively, as shown in fig. 14, a schematic diagram of the energy absorption process of the energy discharging device 10 when a fault occurs in a certain converter station is shown.
When a fault occurs in the converter station and the control module 102 fails, the operation of the energy discharging device 10 is as follows:
and S501, when the station internal fault occurs in the receiving end converter station, locking the receiving end converter station in the operating VSC and sending an operation command to the energy leakage device 10.
S502, after the energy discharging device 10 receives the operation command, the control module 102 cannot be turned on. An instruction is issued to turn on the protection module 104.
S503, the protection module 104 is conducted.
And S504, tripping the VSC alternating current circuit breaker.
When a fault occurs in the converter station and both the control module 102 and the protection module 104 fail, the operation of the energy discharging device 10 is as follows:
s601, when an intra-station fault occurs in the receiving end converter station, the receiving end converter station is locked in the operating VSC, and an operation command is issued to the energy release device 10.
S602, after the energy discharging device 10 receives the operation command, the control module 102 cannot be turned on. An instruction is issued to turn on the protection module 104.
S603, the protection module 104 refuses to operate. At this time, both the energy scavenging device 10 and the VSC are at risk of damage.
The invention also comprises a high voltage power transmission system comprising the energy discharge device 10 provided in the above embodiment. The structure of a specific high voltage power transmission system can be referred to fig. 1 and the corresponding description of fig. 1 above. In addition, those skilled in the art can design a high-voltage power transmission system with other structures than the direct-current power transmission system shown in fig. 1 according to actual needs. The invention is not limited in this respect.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Claims (11)
1. A energy discharging device is applied to a high-voltage direct-current transmission system, and is characterized in that a first end of the energy discharging device is used for being connected with a high-voltage end of a Voltage Source Converter (VSC), and a second end of the energy discharging device is used for being connected with a grounding end of the Voltage Source Converter (VSC);
the energy leakage device comprises a fixed energy leakage element and a control module; wherein: the fixed energy-discharging element and the control module are connected in series between the first end of the energy-discharging device and the second end of the energy-discharging device;
the first end of the control module is connected with the first end of the energy leakage device, and the second end of the control module is connected with the first end of the fixed energy leakage element; the second end of the fixed energy-discharging element is connected with the first end of the energy-discharging device;
or the first end of the fixed energy-discharging element is connected with the first end of the energy-discharging device, and the second end of the fixed energy-discharging element is connected with the first end of the control module; the second end of the control module is connected with the second end of the energy leakage device;
the fixed energy discharging element comprises a plurality of energy dissipation units connected in series between a first end and a second end of the fixed energy discharging element;
the control module is configured to conduct a first end and a second end of the control module when it is detected that the voltage carried by the VSC is greater than a threshold voltage.
2. The energy discharging device of claim 1, wherein the fixed energy discharging element comprises a plurality of energy dissipating units that are nonlinear resistive elements;
the energy discharge device further comprises a controlled energy discharge element; the controlled energy discharge element comprises a plurality of energy dissipation units connected in series between a first end and a second end of the controlled energy discharge element; the controlled energy discharge element comprises a plurality of energy dissipation units which are nonlinear resistance elements;
the first end of the controlled energy leakage element is connected with the first end of the control module, and the second end of the controlled energy leakage element is connected with the second end of the control module.
3. The energy discharging device according to claim 1, wherein the control module, in particular comprising a first fast switching unit and a first mechanical breaker; wherein the first fast switching unit and the first mechanical breaker are connected in parallel between the first end and the second end of the control module; the first mechanical breaker is used for converting current and switching off direct current when the protection module is withdrawn; the first fast switch unit specifically includes: the quick switch-on mechanical switch is one of a controllable trigger gap switch or a power electronic switch.
4. The energy discharging device according to claim 3, wherein the power electronic switch specifically comprises: the semi-control type power electronic device or the full-control type power electronic device, and a dynamic and stable state voltage-sharing element, a reactor and a series mechanical switch for auxiliary current interruption which are matched with the semi-control type power electronic device or the full-control type power electronic device.
5. The apparatus according to claim 1, further comprising a protection module;
the first end of the protection module is connected with the first end of the energy leakage device, and the second end of the protection module is connected with the second end of the energy leakage device;
the protection module is used for conducting a path between the first end and the second end of the protection module when the temperature of the energy leakage device is greater than a threshold temperature or the energy absorbed by the energy leakage device reaches an energy threshold.
6. The discharging device according to claim 5, wherein the protection module, in particular comprising a second fast switching unit and a second mechanical circuit breaker; wherein the second fast switching unit and the second mechanical breaker are connected in parallel between the first end and the second end of the protection module;
the second fast switch unit specifically includes: the quick switch-on mechanical switch is one of a controllable trigger gap switch or a power electronic switch.
7. The discharging device according to claim 6, wherein the power electronic switch specifically includes but is not limited to: the semi-control type power electronic device or the full-control type power electronic device, and a dynamic and stable state voltage-sharing element, a reactor and a series mechanical switch for auxiliary current interruption which are matched with the semi-control type power electronic device or the full-control type power electronic device.
8. The apparatus according to any of claims 1-7, further comprising: a refrigeration module; the refrigeration module is used for reducing the ambient temperature of an energy dissipation unit in the energy leakage device.
9. The energy discharging device according to any one of claims 1 to 7, wherein the control module is configured to conduct the first end and the second end of the control module when detecting that an average value of the capacitor voltages of each of a plurality of sub-modules included in the VSC is greater than a threshold voltage.
10. The energy release device according to any of claims 5-7, wherein the protection module is further configured to conduct the first end and the second end of the protection module when detecting that the voltage carried by the VSC is greater than a threshold voltage and the control module fails.
11. A high voltage power transmission system comprising a power dump device as claimed in any one of claims 1 to 10.
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| Application Number | Priority Date | Filing Date | Title |
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| CN2019106315648 | 2019-07-12 | ||
| CN201910631564.8A CN110277778A (en) | 2019-07-12 | 2019-07-12 | One kind is let out can device |
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| CN110649585A true CN110649585A (en) | 2020-01-03 |
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| CN201910631564.8A Withdrawn CN110277778A (en) | 2019-07-12 | 2019-07-12 | One kind is let out can device |
| CN201910937302.4A Pending CN110649585A (en) | 2019-07-12 | 2019-09-29 | Energy discharge device and high-voltage power transmission system |
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| CN201910631564.8A Withdrawn CN110277778A (en) | 2019-07-12 | 2019-07-12 | One kind is let out can device |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111585256A (en) * | 2020-05-22 | 2020-08-25 | 西安许继电力电子技术有限公司 | Control method and device for hybrid cascade multi-end converter valve |
| CN111999578A (en) * | 2020-08-10 | 2020-11-27 | 许继集团有限公司 | Controllable lightning arrester simulation test method and device |
| CN112688288A (en) * | 2020-12-25 | 2021-04-20 | 中国电力工程顾问集团中南电力设计院有限公司 | Overvoltage control protection method for submodule of symmetrical bipolar flexible direct-current power transmission system |
| CN114629098A (en) * | 2022-02-23 | 2022-06-14 | 中国科学院电工研究所 | Solid-state switch based on sectional type gapless lightning arrester and utilization rate improving method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112509857B (en) * | 2020-09-25 | 2023-04-07 | 平高集团有限公司 | Combined high-voltage direct-current bypass switch |
| CN113708356A (en) * | 2021-06-17 | 2021-11-26 | 中国电力科学研究院有限公司 | Trigger gap switch small current follow current device for controlling direct current controllable lightning arrester |
-
2019
- 2019-07-12 CN CN201910631564.8A patent/CN110277778A/en not_active Withdrawn
- 2019-09-29 CN CN201910937302.4A patent/CN110649585A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111585256A (en) * | 2020-05-22 | 2020-08-25 | 西安许继电力电子技术有限公司 | Control method and device for hybrid cascade multi-end converter valve |
| CN111585256B (en) * | 2020-05-22 | 2022-08-19 | 西安许继电力电子技术有限公司 | Control method and device for hybrid cascade multi-end converter valve |
| CN111999578A (en) * | 2020-08-10 | 2020-11-27 | 许继集团有限公司 | Controllable lightning arrester simulation test method and device |
| CN112688288A (en) * | 2020-12-25 | 2021-04-20 | 中国电力工程顾问集团中南电力设计院有限公司 | Overvoltage control protection method for submodule of symmetrical bipolar flexible direct-current power transmission system |
| CN114629098A (en) * | 2022-02-23 | 2022-06-14 | 中国科学院电工研究所 | Solid-state switch based on sectional type gapless lightning arrester and utilization rate improving method thereof |
| CN114629098B (en) * | 2022-02-23 | 2022-11-11 | 中国科学院电工研究所 | Solid-state switch based on sectional type gapless lightning arrester and utilization rate improving method thereof |
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|---|---|
| CN110277778A (en) | 2019-09-24 |
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