CN217282225U - Controllable energy dissipation device of alternating current system - Google Patents
Controllable energy dissipation device of alternating current system Download PDFInfo
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- CN217282225U CN217282225U CN202220441600.1U CN202220441600U CN217282225U CN 217282225 U CN217282225 U CN 217282225U CN 202220441600 U CN202220441600 U CN 202220441600U CN 217282225 U CN217282225 U CN 217282225U
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Abstract
The utility model discloses an AC system energy dissipater, include: the first energy dissipation unit is connected with the second energy dissipation unit in series, the second energy dissipation unit is connected with the bypass switches, and when the alternating current system is overvoltage, the control module enables the energy dissipation sub-units to be gradually connected into the alternating current bus by controlling the on-off state of each bypass switch in a two-stage control connection mode or a multi-stage control connection mode so as to inhibit the overvoltage of the alternating current system; when the alternating current system is in fault undervoltage, the control module controls the connection mode in a multistage mode, and the on-off state of each bypass switch is controlled, so that the energy dissipation subunits are gradually connected into the alternating current bus to suppress the overvoltage of the alternating current system, and the energy dissipation modules can be gradually connected into the alternating current bus only by utilizing the bypass switches to suppress the overvoltage of the alternating current system.
Description
Technical Field
The utility model relates to a direct current transmission technology field, concretely relates to controllable energy absorber of alternating current system.
Background
The extra-high voltage direct current transmission converter needs a large amount of reactive power and is usually compensated in a converter station by adopting a mode of installing a filter station on site. In the process, surplus reactive power brought by a filtering station brings larger transient overvoltage to a transmitting end alternating current system, and the overvoltage is increased along with the surplus of power and the increase of equivalent reactance of a line. The alternating current system fault causes that the new energy station transmits extra reactive power and also causes overvoltage at the later stage of fault recovery, and moreover, the overvoltage of the ultra-high voltage transmission end alternating current system is influenced by the cross of various factors, and the overvoltage phenomenon of the transmission end alternating current power grid is caused by different degrees of phase change failure, direct current single-pole and double-pole locking and the like. Overvoltage caused by the problems seriously restricts the safe and stable operation of a sending-end alternating current system, particularly the overvoltage of a weak alternating current system is more obvious, the suppression of the overvoltage of the sending-end alternating current system is also widely researched, the three types of solutions exist, and the existing solutions include the following three types: the method comprises the following steps: the method can reduce the overvoltage through the optimization control from the control source. By optimizing the control parameters, the response speed of the system can be effectively increased to control the reactive compensation amount, so that the overvoltage is maintained within a lower level. The coordination of the receiving end and the reactive compensation of the transmitting end can effectively reduce the overvoltage of the alternating current system of the transmitting end. However, this method has a high requirement for control, and may also require coordinated communication between the sending end and the receiving end, which reduces the reliability of the system. Meanwhile, the unified setting of parameters under different new energy stations is also difficult; the second method comprises the following steps: the method suppresses the overvoltage in terms of increasing the system short-circuit ratio, compared to the power surplus. Although it is possible to suppress the system overvoltage by increasing the short-circuit ratio and decreasing the system line impedance, generally, a reactive compensation method such as a line series capacitor generates harmonics to reduce the power quality, and also causes the system to oscillate. Moreover, the modification of the line corridor or the addition of a reactive power adjusting device has larger consumable material for the existing extra-high voltage direct current transmission system; the third method comprises the following steps: passive energy consumption type, by introducing energy consumption device, eliminates power surplus during fault period so as to effectively reduce overvoltage, and its effect is limited by type of energy consumption device and its corresponding control switching mode.
SUMMERY OF THE UTILITY MODEL
Therefore, the to-be-solved technical problem of the present invention lies in overcoming the defect that the overvoltage suppression method of the ac system in the prior art easily leads to the system to oscillate and has high requirement on the control method, thereby providing a controllable energy dissipation device of the ac system.
In order to achieve the above purpose, the utility model provides a following technical scheme:
in a first aspect, an embodiment of the present invention provides a controllable energy dissipation device for ac system, which is characterized in that, include: the energy dissipation device comprises a plurality of energy dissipation modules and a control module, wherein an alternating current system is connected with the network side of a transformer through a three-phase alternating current bus, each energy dissipation module is connected with a one-phase alternating current bus, and the energy dissipation modules are connected in a star or angle connection mode; each energy dissipation module comprises a first energy dissipation unit, a second energy dissipation unit and at least one bypass switch, each energy dissipation unit is formed by connecting a plurality of energy dissipation subunits in series, and one bypass switch is connected with the energy dissipation subunits of the second energy dissipation units which are connected in series and correspond to the preset number of energy dissipation subunits in parallel; the control module is connected with each energy dissipation module and the alternating current system and used for judging whether the alternating current system is overvoltage or not or the alternating current system is under-voltage due to fault, and when the alternating current system is overvoltage, the control module enables the energy dissipation subunits to be gradually connected into the alternating current bus in a two-stage control connection mode or a multi-stage control connection mode based on the current alternating current system voltage and rated voltage so as to inhibit the alternating current system overvoltage; when the alternating current system is in fault undervoltage, the control module enables the energy dissipation subunit to be gradually connected into the alternating current bus in a multi-level control connection mode based on the current alternating current system voltage and the rated voltage so as to restrain the alternating current system overvoltage; when the energy dissipation subunits are gradually connected, the number of the energy dissipation subunits connected to the alternating current bus at each time is determined by the current alternating current system voltage and the rated voltage.
In an embodiment, in the two-stage control access mode, the number of the bypass switches is 1, and the bypass switches are connected in parallel with the second energy dissipation unit.
In one embodiment, in the multi-level control access mode, the bypass switches are connected in parallel to form a plurality of bypass switches, wherein the number of the energy dissipation subunits of one bypass switch connected in parallel with the second energy dissipation unit is determined by the number of the energy dissipation subunits accessed each time.
In one embodiment, the energy dissipating subunit is an arrester.
In one embodiment, the bypass switch is a power electronic switch.
In a second aspect, an embodiment of the present invention provides an application method of a controllable energy dissipater of an ac system, which is characterized in that, based on the controllable energy dissipater of the ac system of the first aspect, the application method includes: the control module judges whether the current alternating current system fails and whether the voltage of the energy dissipater is in an undervoltage state or not, or the current alternating current system does not fail and the voltage of the energy dissipater is in an overvoltage state; when the current alternating current system has a fault and the voltage of the energy dissipation device is in an undervoltage state, the control module enables the energy dissipation subunits to be gradually connected into the alternating current bus in a multi-level control connection mode based on the current alternating current system voltage and the rated voltage so as to restrain the overvoltage of the alternating current system; when the current alternating current system is not in fault and the voltage of the energy dissipator is in an overvoltage state, the control module enables the energy dissipator units to be gradually connected into the alternating current bus in a two-stage control connection mode or a multi-stage control connection mode based on the current alternating current system voltage and the rated voltage so as to restrain the alternating current system overvoltage.
In an embodiment, when the current ac system fails and the voltage of the energy dissipater is in an under-voltage state, the process of gradually accessing the energy dissipater sub-units to the ac bus by the control module in a multi-level control access mode based on the current ac system voltage and the rated voltage includes: the control module acquires a plurality of first preset voltage thresholds which are sequentially increased in an increasing mode, wherein the largest first preset voltage threshold is smaller than the maximum bearing voltage of the alternating current system, the smallest first preset voltage threshold is larger than the rated voltage, and each first preset voltage threshold corresponds to the number of energy dissipation subunits of a corresponding second energy dissipation unit which needs to be connected to the alternating current bus; the control module judges whether the voltage of the energy dissipater is lower than the rated voltage of a first preset multiple, when the voltage of the energy dissipater is lower than the rated voltage of the first preset multiple, all bypass switches are controlled to be in a closed state, a first energy dissipation unit is connected to an alternating current bus, and the first preset multiple is a numerical value smaller than 1; in the process that the voltage of the energy dissipater is reduced to a rated voltage after rising to a maximum bearing voltage, the control module obtains the voltage of the current energy dissipater in real time and determines a first preset voltage threshold value which is closest to the voltage of the current energy dissipater and is larger than the voltage of the energy dissipater; and according to the first preset voltage threshold value, the control module determines the number of energy dissipation subunits of the second energy dissipation unit corresponding to the control module, which need to be connected to the alternating current bus, and switches off the corresponding bypass switch.
In one embodiment, when the current ac system is not faulty and the voltage of the energy dissipator is in an overvoltage state, the control module gradually accesses the energy dissipator to the ac bus in a two-stage control access manner based on the current ac system voltage and the rated voltage, and the process includes: the control module judges whether the voltage of the current energy dissipater is higher than the rated voltage of a second preset multiple, wherein the second preset multiple is a numerical value larger than 1; when the voltage of the current energy dissipation device is higher than the rated voltage of a second preset multiple, the control module closes the bypass switch, bypasses the second energy dissipation unit, and connects the first energy dissipation unit to the alternating current bus; judging whether the voltage of the current energy dissipater is higher than the rated voltage of a third preset multiple, wherein the third preset multiple is smaller than the first preset multiple and is a numerical value larger than 1; when the voltage of the current energy dissipation device is higher than the rated voltage of a third preset multiple, the control module disconnects the bypass switch, and the first energy dissipation unit and the second energy dissipation unit are connected to the alternating current bus.
In an embodiment, when the current ac system is not in fault and the voltage of the energy dissipater is in an overvoltage state, the process of gradually connecting the energy dissipater subunit to the ac bus by the control module in a multi-level control connection mode based on the current ac system voltage and the rated voltage includes: the control module acquires a plurality of second preset voltage thresholds which are sequentially increased in an increasing mode, wherein the largest second preset voltage threshold is smaller than the maximum bearing voltage of the alternating current system, the smallest second preset voltage threshold is larger than the rated voltage, and each second preset voltage threshold corresponds to the number of energy dissipation subunits of a corresponding second energy dissipation unit which needs to be connected to the alternating current bus; the control module judges whether the voltage of the energy dissipater is higher than the rated voltage of a fourth preset multiple, when the voltage of the energy dissipater is lower than the rated voltage of the fourth preset multiple, all the bypass switches are controlled to be in a closed state, the first energy dissipation unit is connected to the alternating current bus, and the rated voltage of the fourth preset multiple is larger than a maximum second preset voltage threshold value; in the process that the voltage of the energy dissipater is reduced to the rated voltage after rising to the maximum bearing voltage, the control module acquires the voltage of the current energy dissipater in real time and determines a second preset voltage threshold value which is closest to the voltage of the current energy dissipater and is greater than the voltage of the energy dissipater; and according to the second preset voltage threshold, the control module determines the number of energy dissipation subunits of the second energy dissipation unit corresponding to the second preset voltage threshold, which need to be connected to the alternating current bus, and switches off the corresponding bypass switch.
In a third aspect, an embodiment of the present invention provides a computer device, including: at least one processor, and a memory communicatively coupled to the at least one processor, wherein the memory stores instructions executable by the at least one processor, the instructions being executable by the at least one processor to cause the at least one processor to perform a method for applying the ac system controllable energy dissipater of the first aspect of the embodiments of the present invention.
In a fourth aspect, the present invention provides a computer-readable storage medium, where computer instructions are stored, and the computer instructions are used to enable a computer to execute the present invention provides a method for applying a controllable energy dissipater of an ac system according to the first aspect.
The utility model discloses technical scheme has following advantage:
the utility model provides an AC system energy dissipater, first energy dissipation unit and second energy dissipation unit series connection, the second energy dissipation unit is connected with bypass switch, when the AC system overvoltage, control module makes energy dissipation subelement gradually insert the AC generating line through controlling the break-make state of each bypass switch in two-stage control access mode or multi-stage control access mode to restrain the AC system overvoltage; when the alternating current system is in fault undervoltage, the control module controls the connection mode in a multistage mode, and the on-off state of each bypass switch is controlled, so that the energy dissipation subunits are gradually connected into the alternating current bus to suppress the overvoltage of the alternating current system, and the energy dissipation modules can be gradually connected into the alternating current bus only by utilizing the bypass switches to suppress the overvoltage of the alternating current system.
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 embodiments or the technical solutions in the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1(a) and fig. 1(b) are respectively a composition diagram of a specific example of an ac system energy dissipater provided by an embodiment of the present invention;
fig. 2(a) and fig. 2(b) are respectively a composition diagram of a specific example of an ac system energy dissipater according to an embodiment of the present invention;
figure 3 is a composition diagram of a specific example of an energy dissipating module provided by an embodiment of the present invention;
fig. 4(a) -fig. 4(d) are respectively verification waveform diagrams provided by the embodiment of the present invention;
fig. 5 is a block diagram of a specific example of a computer device according to an embodiment of the present invention.
Detailed Description
The technical solution of the present invention will be described clearly and completely with reference to the accompanying drawings, and obviously, the described embodiments are some, but not all embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; the two elements may be directly connected or indirectly connected through an intermediate medium, or may be communicated with each other inside the two elements, or may be wirelessly connected or wired connected. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Furthermore, the technical features mentioned in the different embodiments of the invention described below can be combined with each other as long as they do not conflict with each other.
Example 1
The embodiment of the utility model provides a controllable energy dissipater of alternating current system is applied to the occasion of restraineing alternating current system overvoltage, as shown in fig. 1(a) and fig. 1(b), the controllable energy dissipater of alternating current system includes: a plurality of energy dissipation modules 1 and a control module 2.
As shown in fig. 1(a) and 1(b), the ac system is connected to the transformer grid side via a three-phase ac bus, each energy dissipation module is connected to a one-phase ac bus, and the energy dissipation modules are connected in a star or delta connection.
As shown in fig. 1(a) and fig. 1(b), the control module of the embodiment of the present invention is connected to each energy dissipation module and the ac system, and is configured to determine whether the ac system is overvoltage or not, or the ac system is under-voltage due to fault, when the ac system is overvoltage, the control module gradually accesses the ac bus to suppress the ac system overvoltage based on the current ac system voltage and the rated voltage in a two-stage control access manner or a multi-stage control access manner; when the alternating current system is in fault undervoltage, the control module enables the energy dissipation subunit to be gradually connected into the alternating current bus in a multi-level control connection mode based on the current alternating current system voltage and the rated voltage so as to restrain the alternating current system overvoltage; when the energy dissipation subunits are gradually connected, the number of the energy dissipation subunits connected to the alternating current bus at each time is determined by the current alternating current system voltage and the rated voltage.
The utility model discloses every energy dissipation module all includes first energy dissipation unit 11, second energy dissipation unit 12 and at least one bypass switch 13, every energy dissipation unit comprises a plurality of energy dissipation subelements 111 series connection, a bypass switch and the energy dissipation subelement parallel connection of the second energy dissipation unit of the series connection of corresponding predetermined quantity, wherein, the energy dissipation subelement can not be limited to the arrester, still can be for other power consumption devices, bypass switch can not be limited to power electronic switch, still can be for other switches.
Specifically, in the embodiment of the present invention, when only one bypass switch is provided, as shown in fig. 2(a), the star-connected energy dissipation module is connected in parallel to the bypass switch and the second energy dissipation unit, and the closing of the bypass switch can bypass all the energy dissipation subunits of the second energy dissipation unit, at this time, when the ac system is in overvoltage, the control module accesses the ac bus by using the two-stage control access mode, and then accesses all the first energy dissipation unit and the second energy dissipation unit to the ac bus.
Specifically, in the embodiment of the present invention, when there are at least two bypass switches, as shown in fig. 2(b), the star-connected energy dissipation modules are connected in series, the closing of the bypass switches can bypass part of the energy dissipation subunits of the second energy dissipation unit, wherein the number of the energy dissipation subunits of the parallel second energy dissipation unit of one bypass switch is determined by the number of the energy dissipation subunits connected in series at each time, at this time, when the ac system is in overvoltage, the control module connects the first energy dissipation unit into the ac bus in a multi-level control manner, and then gradually connects the energy dissipation subunits of the second energy dissipation unit into the ac bus again until the first energy dissipation unit and the second energy dissipation unit are all connected into the ac bus.
It should be noted that the energy dissipater of the ac system according to the embodiment of the present invention may only include a plurality of energy dissipaters, and the control module is replaced by the controller of the ac system, without specially setting a hardware structure of a control module.
Example 2
The embodiment of the utility model provides an application method of controllable energy dissipater of alternating current system, based on the controllable energy dissipater of alternating current system of embodiment 1, application method includes:
step S11: the control module judges whether the current alternating current system fails and whether the voltage of the energy dissipater is in an undervoltage state or not, or the current alternating current system does not fail and the voltage of the energy dissipater is in an overvoltage state.
Step S12: when the current alternating current system has a fault and the voltage of the energy dissipation device is in an undervoltage state, the control module enables the energy dissipation subunits to be gradually connected into the alternating current bus in a multi-level control connection mode based on the current alternating current system voltage and the rated voltage so as to restrain the overvoltage of the alternating current system; when the current alternating current system is not in fault and the voltage of the energy dissipation device is in an overvoltage state, the control module enables the energy dissipation subunits to be gradually connected into the alternating current bus in a two-stage control connection mode or a multi-stage control connection mode based on the current alternating current system voltage and the rated voltage so as to restrain the overvoltage of the alternating current system.
Specifically, when the energy dissipater of the embodiment of the present invention is in the structure as shown in fig. 2(a) (fig. 2(a) only uses star connection between energy dissipater modules, and here also can use angle connection), when the ac system is overvoltage, it is possible to use a two-stage control access mode, first access the first energy dissipater to the ac bus, and bypass the second energy dissipater, and then, after the voltage of the energy dissipater (phase voltage of the energy dissipater when star connection, line voltage of the energy dissipater when angle connection) satisfies the preset condition, access the second energy dissipater to the ac bus, and at this moment, the first energy dissipater and the second energy dissipater all access the ac bus, thereby suppressing the ac system overvoltage and consuming the extra energy of the ac system.
Specifically, when the energy dissipater according to the embodiment of the present invention is configured as shown in fig. 2(b) (fig. 2(b) is only connected in star shape, and may also be connected in angle shape), when the ac system is over-voltage, the first energy dissipater unit may be connected to the ac bus, and the second energy dissipater unit may be bypassed, and then, in the recovery process of the voltage of the energy dissipater (phase voltage of the energy dissipater in star connection, and line voltage of the energy dissipater in angle shape connection), that is, in the recovery process of the voltage of the energy dissipater after overvoltage, when the voltage of the energy dissipater reaches the rated voltage, each time the voltage of the energy dissipater reaches a preset condition, a part of the energy dissipater subunits of the second energy dissipater unit and the first energy dissipater unit are connected to the ac bus, and as the voltage of the energy dissipater decreases, the number of the energy dissipater subunits connected to the ac bus increases, until all the energy dissipation subunits are connected to the AC bus.
Specifically, when the utility model discloses energy dissipater is when the structure as shown in fig. 2(b) (fig. 2(b) only with star connection between the energy dissipation module, here also can be for the angular connection), when the ac system trouble is undervoltage, can take place because the overvoltage condition behind the undervoltage that the ac system trouble leads to, when energy dissipater's voltage is undervoltage, insert alternating current bus with first energy dissipation unit, later, in-process that recovers rated voltage after energy dissipater's voltage is overvoltage, energy dissipater's voltage is every to reach a preset condition, then insert alternating current bus with some energy dissipation subelements of second energy dissipation unit, first energy dissipation unit, and along with energy dissipater's voltage's decline, the quantity of the energy dissipation subelement who inserts alternating current bus is more and more, all insert alternating current bus up to whole energy dissipation subelements.
In a specific embodiment, when the current ac system fails and the voltage of the energy dissipator is in an under-voltage state, the process of gradually accessing the energy dissipator sub-units to the ac bus by the control module in a multi-level control access manner based on the current ac system voltage and the rated voltage includes:
step S21: the control module obtains a plurality of first preset voltage thresholds which are sequentially increased, wherein the largest first preset voltage threshold is smaller than the maximum bearing voltage of the alternating current system, the smallest first preset voltage threshold is larger than the rated voltage, and each first preset voltage threshold corresponds to the number of energy dissipation subunits of the corresponding second energy dissipation units which need to be connected to the alternating current bus.
Specifically, in the embodiment of the present invention, when the energy dissipater is configured as shown in fig. 2(b) (fig. 2(b) is only connected in star shape, and may also be connected in angle shape, when the ac system fails and is under-voltage, that is, when overvoltage after under-voltage caused by failure of the ac system may occur, in order to realize multi-stage control over the energy dissipater, first, the maximum withstand voltage of the ac system is determined, where the maximum withstand voltage is determined by actual conditions of the ac system, and the actual conditions may include the maximum withstand voltages of components of the ac system, and then, a plurality of first preset voltage thresholds are set between the maximum withstand voltage and the rated voltage of the ac system, and the first preset voltage thresholds show an increasing trend, and the number of energy dissipater units of the second energy dissipater to be connected to the ac bus corresponding to each first preset voltage threshold is determined, and the number of the energy dissipation subunits of the second energy dissipation unit which need to be connected to the alternating current bus is increased along with the increase of the first preset voltage threshold.
Specifically, the embodiment of the present invention provides a plurality of first preset voltage thresholds between the maximum withstand voltage and the rated voltage, as shown in formula (1).
V peak <β n V peak <β n-1 V peak …<β 2 V peak <β 1 V peak <α 1 V peak (1)
In the formula (1), V peak To rated voltage, alpha 1 V peak To the maximum withstand voltage, beta n V peak 、β n-1 V peak 、……、β 2 V peak 、β 1 V peak Are all the first preset voltage threshold value, wherein, 1<β n <β n-1 <……<β 2 <β 1 <α 1 。
Each first predetermined voltage threshold β n V peak 、β n-1 V peak 、……、β 2 V peak 、β 1 V peak The number Nb of the corresponding energy dissipation subelements of the second energy dissipation element needing to be connected to the alternating current bus n 、Nb n-1 、……、 Nb 2 、Nb 1 As shown in formula (2).
Nb n <Nb n-1 <...<Nb 2 <Nb 1 (2)
In formula (2), Nb n The number of total energy dissipating sub-units in the second energy dissipating unit.
When the utility model discloses the energy dissipater is when the structure as shown in figure 2(b) (figure 2(b) only with star connection between the energy dissipation module, here also can be for the angular form connection), the quantity of bypass switch this moment is the same with the quantity of first predetermined voltage threshold value, and the energy dissipation subunit's of the second energy dissipation unit that bypass switch can the bypass number is respectively: nb 1 、Nb 2 -Nb 1 、Nb 3 -Nb 2 ……Nb n-1 -Nb n-2 、 Nb n -Nb n-1 。
In addition, when carrying out multistage control to the energy dissipation module, the number of energy dissipation subelements of the second energy dissipation unit that bypass switch can the bypass can also be respectively: nb 1 、Nb 2 、Nb 3 ……Nb n-1 、Nb n Then the connection of the bypass switch and the second energy dissipating unit is shown in fig. 3.
Step 22: the control module judges whether the voltage of the energy dissipation device is lower than the rated voltage of a first preset multiple, when the voltage of the energy dissipation device is lower than the rated voltage of the first preset multiple, all the bypass switches are controlled to be in a closed state, the first energy dissipation unit is connected to the alternating current bus, and the first preset multiple is a numerical value smaller than 1.
In particular, the voltage of the dissipator (phase voltage of the dissipator in star connection, line voltage of the dissipator in angular connection) is lower than a nominal voltage α of a first preset multiple 2 V peak ，α 2 And for a first preset multiple, all bypass switches are closed firstly, all the energy dissipation subunits of the second energy dissipation unit are bypassed, and the first energy dissipation unit is connected into the alternating current bus.
Step S23: and in the process that the voltage of the energy dissipater is reduced to the rated voltage after rising to the maximum bearing voltage, the control module acquires the voltage of the current energy dissipater in real time and determines a first preset voltage threshold which is closest to the voltage of the current energy dissipater and is greater than the voltage of the energy dissipater.
Step S24: and according to the first preset voltage threshold value, the control module determines the number of energy dissipation subunits of the second energy dissipation unit corresponding to the first preset voltage threshold value, which need to be connected to the alternating current bus, and switches off the corresponding bypass switch.
Specifically, after the alternating current system fails, the voltage of the alternating current system is firstly reduced and then boosted, and the first energy dissipation unit is connected to the alternating current bus, at this time, the first energy dissipation unit consumes redundant energy of the alternating current system, so that the voltage of the alternating current system does not rise all the time, the voltage of the alternating current system rises and then falls, namely the voltage of the energy dissipation device also tends to rise and fall.
Specifically, as shown in formula (3), wherein α is 2 <1<β n <β n-1 <…<β 1 <α 1 ，N＝Na+Nb n When the voltage of the energy dissipater is lower than the rated voltage alpha of the first preset multiple 2 V peak And then, in the process that the energy dissipater rises to the maximum bearing voltage and then is reduced to the rated voltage, when the voltage V of the energy dissipater is in beta 2 V peak 、β 1 V peak In time of (i) beta 2 V peak <V<β 1 V peak When it is, Nb is n -Nb 1 An energy dissipating subunit bypass of a second energy dissipating unit, in this case Nb 1 The second energy dissipation unitThe energy subunit and the first energy dissipation unit are connected to an alternating current bus, and when the voltage V of the energy dissipation device is in beta 3 V peak 、β 2 V peak In time of (i) beta 3 V peak <V<β 2 V peak When it is, Nb is n -Nb 2 An energy dissipating subunit bypass of a second energy dissipating unit, in this case Nb 2 The energy dissipation subunit and the first energy dissipation unit of the second energy dissipation unit are connected to an alternating current bus, and so on, when the voltage V of the energy dissipation device is at V peak 、β n V peak In between, i.e. V peak <V<β n V peak When it is, Nb is n The energy dissipation subunit of the second energy dissipation unit and the first energy dissipation unit are connected to the alternating current bus, so that the energy dissipation subunit of the second energy dissipation unit is connected to the alternating current bus step by step.
In a specific embodiment, when the current ac system is not in fault and the voltage of the energy dissipater is in an overvoltage state, the process of gradually connecting the energy dissipater subunit to the ac bus by the control module in a two-stage control connection mode based on the current ac system voltage and the rated voltage includes:
step S31: the control module judges whether the voltage of the current energy dissipater is higher than the rated voltage of a second preset multiple, wherein the second preset multiple is a numerical value larger than 1.
Step S32: when the voltage of the current energy dissipation device is higher than the rated voltage of a second preset multiple, the control module closes the bypass switch, bypasses the second energy dissipation unit, and connects the first energy dissipation unit to the alternating current bus.
The embodiment of the utility model provides a except involving alternating current system trouble overvoltage, still relate to alternating current system because the overvoltage of reasons such as commutation failure, when alternating current system overvoltage, control module can utilize two-stage control access mode or multi-stage control access mode, makes the energy dissipater access alternating current generating line to consume the unnecessary energy of alternating current generating line, restrain the overvoltage.
Specifically, when the energy dissipater is in the structure shown in fig. 2(a) (fig. 2(a) only star-connected energy dissipater modules, here also angle-connected), the control module first determines whether the voltage V of the energy dissipater (phase voltage of the energy dissipater in star-connected and line voltage of the energy dissipater in angle-connected) is lower than a second predetermined multiple of the rated voltage α 3 V peak ，α 3 Is a second predetermined multiple below alpha 3 V peak And when the first energy dissipation unit is connected with the alternating current bus, the bypass switch is closed.
Step S33: and judging whether the voltage of the current energy dissipater is higher than the rated voltage of a third preset multiple, wherein the third preset multiple is smaller than the first preset multiple and is a numerical value larger than 1.
Step S34: when the voltage of the current energy dissipation device is higher than the rated voltage of a third preset multiple, the control module disconnects the bypass switch, and the first energy dissipation unit and the second energy dissipation unit are connected to the alternating current bus.
Specifically, as shown in formula (4), wherein 1 is<α 4 <α 3 When the voltage V of the energy dissipater is lower than the rated voltage alpha of a second preset multiple 3 V peak Rated voltage alpha of second preset multiple 3 V peak When the voltage is less than the maximum bearing voltage of the alternating current system, bypassing the second energy dissipation unit, connecting the first energy dissipation unit to the alternating current bus, connecting Na energy dissipation subunits to the alternating current bus, wherein Na is the number of the energy dissipation subunits of the first energy dissipation unit; when the first energy dissipation unit is connected to the alternating current bus, the voltage of the alternating current system is reduced, namely the voltage of the energy dissipation device is reduced, and when the voltage of the energy dissipation device is reduced to be lower than the rated voltage alpha of a third preset multiple 4 V peak When (alpha) 4 Is a third preset multiple), the bypass switch is switched off, the first energy dissipation unit and the second energy dissipation unit are all connected into the alternating current bus, and then Na + Nb n Each energy dissipation subunit is connected with an alternating current bus, Nb n The number of the energy dissipation subunits of the second energy dissipation unit.
It should be noted that the embodiments of the present invention can also utilize the energy dissipater as shown in fig. 2(b) and fig. 3, wherein only the bypass switch needs to be utilized reasonably to realize that the voltage V at the energy dissipater is lower than the rated voltage α of the second preset multiple 3 V peak When the voltage of the energy dissipater drops to a rated voltage alpha lower than a third preset multiple, the second energy dissipation unit is bypassed 4 V peak And when the first energy dissipation unit and the second energy dissipation unit are connected to the alternating current bus.
In a specific embodiment, when the current ac system is not in fault and the voltage of the energy dissipater is in an overvoltage state, the process of gradually connecting the energy dissipater subunit to the ac bus by the control module in a multi-level control connection mode based on the current ac system voltage and the rated voltage includes:
step S41: the control module obtains a plurality of second preset voltage thresholds which are sequentially increased, wherein the largest second preset voltage threshold is smaller than the maximum bearing voltage of the alternating current system, the smallest second preset voltage threshold is larger than the rated voltage, and each second preset voltage threshold corresponds to the number of energy dissipation subunits of the corresponding second energy dissipation unit which needs to be connected to the alternating current bus.
The embodiment of the utility model provides an in, when the circumstances such as exchange system commutation failure overvoltage, control module can also gradually insert alternating current generating line with first energy dissipation unit and second energy dissipation unit, but after first energy dissipation unit inserts alternating current generating line, the energy dissipation subelement that needs to gradually in the second energy dissipation unit gradually inserts alternating current generating line once more, at this moment, in order to confirm the time of inserting the energy dissipation subelement at every turn, at first need set up a plurality of second that increase progressively in proper order and preset the voltage threshold value, wherein, the setting method is the same with step S21.
Specifically, in the embodiment of the present invention, when the energy dissipater is configured as shown in fig. 2(b) (fig. 2(b) is only connected in star shape between energy dissipater modules, and may also be connected in angle shape here), when the ac system is not in fault and is in overvoltage, in order to realize multi-level control over the energy dissipater modules, first, the maximum withstand voltage of the ac system is determined, which is determined by the actual conditions of the ac system, which may include the maximum withstand voltages of the components of the ac system, and the like, and then, a plurality of second preset voltage thresholds are set between the maximum withstand voltage and the rated voltage of the ac system, and the second preset voltage thresholds show an increasing trend, and the number of energy dissipater subunits of the second energy dissipater units to be connected to the ac bus corresponding to each second preset voltage threshold is determined, wherein, as the second preset voltage thresholds increase, the number of energy dissipation subunits of the second energy dissipation unit which need to be connected to the alternating current bus is increased.
Specifically, the embodiment of the present invention sets up a plurality of first preset voltage thresholds between the maximum withstand voltage and the rated voltage, as shown in formula (5).
V peak <λ n V peak <λ n-1 V peak ...<λ 2 V peak <λ 1 V peak <λ 1 V peak (5)
In the formula (5), V peak To rated voltage, alpha 1 V peak To maximum withstand voltage, λ n V peak 、λ n-1 V peak 、……、λ 2 V peak 、λ 1 V peak Are all the first preset voltage threshold value, wherein, 1<λ n <λ n-1 <……<λ 2 <λ 1 <α 1 。
Each first preset voltage threshold lambda n V peak 、λ n-1 V peak 、……、λ 2 V peak 、λ 1 V peak The number Nb of the corresponding energy dissipation subelements of the second energy dissipation element needing to be connected to the alternating current bus n 、Nb n-1 、……、 Nb 2 、Nb 1 As shown in equation (6).
Nb n <Nb n-1 <...<Nb 2 <Nb 1 (6)
In formula (6), Nb n As the number of total energy dissipating sub-units in the second energy dissipating unit，Nb 1 The number of total energy dissipating subunits in the first energy dissipating unit.
Step S42: the control module judges whether the voltage of the energy dissipater is higher than the rated voltage of a fourth preset multiple, when the voltage of the energy dissipater is lower than the rated voltage of the fourth preset multiple, all the bypass switches are controlled to be in a closed state, the first energy dissipation unit is connected to the alternating current bus, and the rated voltage of the fourth preset multiple is larger than a maximum second preset voltage threshold value.
Step S43: and in the process that the voltage of the energy dissipater is reduced to the rated voltage after rising to the maximum bearing voltage, the control module acquires the voltage of the current energy dissipater in real time and determines a second preset voltage threshold which is closest to the voltage of the current energy dissipater and is greater than the voltage of the energy dissipater.
Step S44: and according to the second preset voltage threshold value, the control module determines the number of energy dissipation subunits of the second energy dissipation unit corresponding to the control module, which need to be connected to the alternating current bus, and switches off the corresponding bypass switch.
Specifically, as shown in formula (7), wherein 1 is<λ n <λ n-1 <……<λ 2 <λ 1 <α 4 <α 1 ，α 4 The voltage of the energy dissipater at the fourth preset multiple is greater than the rated voltage alpha of the fourth preset multiple 4 V peak When the energy dissipater rises to the maximum bearing voltage and then is reduced to the rated voltage, when the voltage V of the energy dissipater is in lambda 2 V peak 、λ 1 V peak In time between, i.e. λ 2 V peak <V<λ 1 V peak When it is, Nb is n -Nb 1 An energy dissipating subunit bypass of a second energy dissipating unit, in this case Nb 1 The energy dissipation subunit of the second energy dissipation unit and the first energy dissipation unit are both connected to an alternating current bus, and when the voltage V of the energy dissipation device is at lambda 3 V peak 、λ 2 V peak In time between, i.e. λ 3 V peak <V<λ 2 V peak When it is, Nb is n -Nb 2 An energy dissipating sub-unit bypass of one second energy dissipating unit,at this time Nb 2 The energy dissipation subunit and the first energy dissipation unit of the second energy dissipation unit are connected to an alternating current bus, and so on, when the voltage V of the energy dissipation device is at V peak 、β n V peak In between, i.e. V peak <V<β n V peak When it is, Nb is n The energy dissipation subunit of the second energy dissipation unit and the first energy dissipation unit are connected to the alternating current bus, so that the energy dissipation subunit of the second energy dissipation unit is connected to the alternating current bus step by step.
In order to further explain the application effect of the embodiment of the present invention, based on the Cigre conventional dc standard model in the PSCAD/EMTDC, transmit-end overvoltage simulation analysis caused by the phase change failure of the receive-end system is performed. Fig. 4(a) -4 (d) show voltage waveforms of the sending end system during failure and recovery of the receiving end commutation when the sending end ac system short-circuit ratio is 2 and 3, respectively. It can be seen in figure 4 that without the energy dissipater proposed above, when the system short circuit ratio is 2, the sink maximum overvoltage will exceed 1.5pu and when the short circuit ratio is 3 the sink maximum overvoltage is about 1.3 pu. In contrast, if the energy dissipater proposed above is employed, the overvoltage can be effectively suppressed within a reasonable level of 1.2 pu. Therefore, the energy dissipater provided by the embodiment of the utility model effectively inhibits the sending end overvoltage caused by the receiving end commutation failure. Of course, the sending end overvoltage caused by other reasons can be inhibited in the same way and is not described in detail.
Example 3
An embodiment of the utility model provides a computer equipment, as shown in fig. 5, include: at least one processor 401, such as a CPU (Central Processing Unit), at least one communication interface 403, memory 404, and at least one communication bus 402. Wherein a communication bus 402 is used to enable connective communication between these components. The communication interface 403 may include a Display (Display) and a Keyboard (Keyboard), and the optional communication interface 403 may also include a standard wired interface and a standard wireless interface. The Memory 404 may be a RAM (random Access Memory) or a non-volatile Memory (non-volatile Memory), such as at least one disk Memory. The memory 404 may optionally be at least one memory device located remotely from the processor 401. Wherein the processor 401 may perform the method of applying the ac system controllable energy dissipater of embodiment 1. A set of program code is stored in the memory 404 and the processor 401 calls the program code stored in the memory 404 for executing the method of applying the alternating system controllable energy dissipater of embodiment 1.
The communication bus 402 may be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus. The communication bus 402 may be divided into an address bus, a data bus, a control bus, and the like. For ease of illustration, only one line is shown in FIG. 5, but this does not represent only one bus or one type of bus.
The memory 404 may include a volatile memory (RAM), such as a random-access memory (RAM); the memory may also include a non-volatile memory (english: non-volatile memory), such as a flash memory (english: flash memory), a hard disk (english: hard disk drive, abbreviated: HDD) or a solid-state drive (english: SSD); the memory 404 may also comprise a combination of memories of the kind described above.
The processor 401 may be a Central Processing Unit (CPU), a Network Processor (NP), or a combination of a CPU and an NP.
The processor 401 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit (ASIC), a Programmable Logic Device (PLD), or a combination thereof. The PLD may be a Complex Programmable Logic Device (CPLD), a field-programmable gate array (FPGA), a General Array Logic (GAL), or any combination thereof.
Optionally, the memory 404 is also used to store program instructions. The processor 401 may call program instructions to implement the method of the present application for implementing the ac system controllable energy dissipater of embodiment 1.
The embodiment of the utility model provides a still provide a computer readable storage medium, the last storage of computer readable storage medium has computer executable instruction, and this computer executable instruction can carry out the application method of the controllable energy dissipater of alternating current system of embodiment 1. The storage medium may be a magnetic Disk, an optical Disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a Flash Memory (Flash Memory), a Hard Disk (Hard Disk Drive, abbreviated as HDD), a Solid-State Drive (SSD), or the like; the storage medium may also comprise a combination of memories of the kind described above.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious changes and modifications can be made without departing from the scope of the invention.
Claims (5)
1. A controllable energy dissipater of an AC system, comprising: a plurality of energy dissipation modules and a control module, wherein,
the alternating current system is connected with the transformer network side through a three-phase alternating current bus, each energy dissipation module is connected with a one-phase alternating current bus, and the energy dissipation modules are connected in a star or angle connection mode;
each energy dissipation module comprises a first energy dissipation unit, a second energy dissipation unit and at least one bypass switch, each energy dissipation unit is formed by connecting a plurality of energy dissipation subunits in series, and one bypass switch is connected with the energy dissipation subunits of the second energy dissipation units which are connected in series and correspond to the preset number of the energy dissipation subunits in parallel;
the control module is connected with each energy dissipation module and the alternating current system and used for judging whether the alternating current system is overvoltage or not or the alternating current system is under-voltage due to fault, and when the alternating current system is overvoltage, the control module enables the energy dissipation subunits to be gradually connected into the alternating current bus in a two-stage control connection mode or a multi-stage control connection mode based on the current alternating current system voltage and rated voltage so as to inhibit the alternating current system overvoltage; when the alternating current system is in fault undervoltage, the control module enables the energy dissipation subunits to be gradually connected into the alternating current bus in a multi-stage control connection mode based on the current alternating current system voltage and the rated voltage so as to restrain the alternating current system overvoltage;
when the energy dissipation subunits are gradually connected, the number of the energy dissipation subunits connected to the alternating current bus at each time is determined by the current alternating current system voltage and the rated voltage.
2. The controllable energy dissipater of an alternating current system according to claim 1, wherein in a two-stage control access mode, the number of the bypass switches is 1, and the bypass switches are connected in parallel with the second energy dissipation unit.
3. The controllable energy dissipater of alternating current system according to claim 1, wherein in the multi-stage control access mode, the bypass switch is connected in parallel to form a plurality of bypass switches, and the number of energy dissipater subunits of one bypass switch connected in parallel with the second energy dissipater is determined by the number of energy dissipater subunits accessed each time.
4. An ac system controllable energy dissipater as claimed in claim 1, wherein said energy dissipater unit is a lightning arrester.
5. An ac system controllable energy dissipater as claimed in claim 1, wherein said bypass switches are power electronic switches.
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