Phase shifting device and control method thereof

Abstract

The present invention discloses a phase-shifting device and a control method thereof. The phase-shifting device is connected in series in the outgoing line of a substation. The phase-shifting device includes: a bypass branch and at least two phase-shifting branches; the bypass branch and the phase-shifting branch are connected in parallel. The phase-shifting branch includes: a first isolating switch, a second isolating switch, a first circuit breaker and a phase-shifting transformer; the first circuit breaker and the phase-shifting transformer are connected in series between the second end of the first isolating switch and the first end of the second isolating switch; the bypass branch includes: a third isolating switch, a fourth isolating switch and a second circuit breaker; the second circuit breaker is connected in series between the second end of the third isolating switch and the first end of the fourth isolating switch. The embodiments of the present invention can improve the safety and reliability of the power system and reduce the difficulty of transportation and installation of the phase-shifting device.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and in particular to a phase shifting device and a control method thereof. Background Art

[0002] With the increasing complexity of power grids and the increasing demand for power supply quality, the interconnection of power grids has become increasingly high, and has developed into a huge power system. As a result, the economy and reliability of the power grid operation and regulation process cannot be guaranteed.

[0003] In order to solve the safety and reliability problems of power transmission lines in power grids and realize the efficient utilization of transmission lines, the existing technology introduces phase-shifting transformers as a means of controlling power flow. The phase-shifting transformer achieves the purpose of controlling power flow by injecting compensation voltage and changing the phase difference between the two ends of the line. The use of phase-shifting transformers can avoid overload and underload of transmission lines or transformer main equipment, improve power supply reliability; and can realize the reasonable distribution of line transmission power, improve the efficiency of transmission channels, and reduce transmission costs. However, in actual application, since the phase-shifting transformer is connected in series in the outgoing line, when the phase-shifting transformer is out of operation due to failure or maintenance, it will affect the normal operation of the line; and in the application scenario of large capacity and high voltage level, the large-capacity phase-shifting transformer is too large, which will cause problems such as inconvenience in transportation and installation. Summary of the invention

[0004] The present invention provides a phase shifting device and a control method thereof, so as to improve the safety and reliability of a power system and reduce the difficulty of transporting and installing the phase shifting device.

[0005] According to one aspect of the present invention, a phase shifting device is provided, wherein the phase shifting device is connected in series to an outgoing line of a substation; the phase shifting device comprises: a bypass branch and at least two phase shifting branches; the bypass branch and the phase shifting branch are connected in parallel;

[0006] The phase-shifting branch comprises: a first isolating switch, a second isolating switch, a first circuit breaker and a phase-shifting transformer; a first end of the first isolating switch is electrically connected to a first connection end of the phase-shifting device; a second end of the second isolating switch is electrically connected to a second connection end of the phase-shifting device; the first circuit breaker and the phase-shifting transformer are connected in series between the second end of the first isolating switch and the first end of the second isolating switch;

[0007] The bypass branch includes: a third isolating switch, a fourth isolating switch and a second circuit breaker; the first end of the third isolating switch is electrically connected to the first connection end of the phase shifting device; the second end of the fourth isolating switch is electrically connected to the second connection end of the phase shifting device; the second circuit breaker is connected in series between the second end of the third isolating switch and the first end of the fourth isolating switch.

[0008] Optionally, the phase-shifting transformer includes: a series transformer and a parallel transformer; wherein the series transformer includes a primary winding and a secondary winding, and the parallel transformer includes a primary winding and a secondary winding;

[0009] The primary winding of the series transformer is connected in series in the phase-shifting branch; a first terminal is led out from the primary winding of the series transformer, and the first terminal is electrically connected to the primary winding of the parallel transformer; a second terminal is led out from the secondary winding of the series transformer, and the second terminal is electrically connected to the secondary winding of the parallel transformer.

[0010] Optionally, the primary winding of the series transformer is directly connected in series in the phase-shifting branch, and the secondary winding of the series transformer adopts a delta connection method;

[0011] The primary winding and the secondary winding of the parallel transformer are both connected in star shape.

[0012] Optionally, the phase shift branch further includes:

[0013] A first lightning arrester, wherein a first end of the first lightning arrester is electrically connected to a neutral point of a primary winding of the shunt transformer, and a second end of the first lightning arrester is grounded;

[0014] a first grounding switch, wherein a first end of the first grounding switch is electrically connected to a neutral point of a primary winding of the shunt transformer, and a second end of the first grounding switch is grounded;

[0015] a second lightning arrester, wherein a first end of the second lightning arrester is electrically connected to a neutral point of a secondary winding of the shunt transformer, and a second end of the second lightning arrester is grounded;

[0016] A second grounding switch, wherein a first end of the second grounding switch is electrically connected to a neutral point of the secondary winding of the parallel transformer, and a second end of the second grounding switch is grounded.

[0017] Optionally, the phase shift branch further includes:

[0018] a third grounding switch; a first end of the third grounding switch is electrically connected to a second end of the first isolating switch, and a second end of the third grounding switch is grounded;

[0019] a fourth grounding switch; a first end of the fourth grounding switch is electrically connected to a first end of the second isolating switch, and a second end of the fourth grounding switch is grounded;

[0020] The bypass branch also includes:

[0021] a fifth grounding switch; a first end of the fifth grounding switch is electrically connected to a second end of the third isolating switch, and a second end of the fifth grounding switch is grounded;

[0022] a sixth grounding switch; a first end of the sixth grounding switch is electrically connected to the first end of the fourth isolating switch, and a second end of the sixth grounding switch is grounded.

[0023] Optionally, the phase-shifting branch further includes: a first current transformer and a second current transformer; the first current transformer and the second current transformer are both connected in series with the phase-shifting transformer, and the first current transformer and the second current transformer are respectively arranged on both sides of the phase-shifting transformer;

[0024] The bypass branch further includes: a third current transformer; the third current transformer and the second circuit breaker are connected in series between the second end of the third isolating switch and the first end of the fourth isolating switch.

[0025] Optionally, the phase shifting device further includes: a fifth isolating switch, a voltage transformer and a third lightning arrester;

[0026] The first end of the fifth isolating switch is electrically connected to the second connection end of the phase shifting device, and the second end of the fifth isolating switch is electrically connected to the voltage transformer; the first end of the third lightning arrester is electrically connected to the second connection end of the phase shifting device, and the second end of the third lightning arrester is grounded.

[0027] According to another aspect of the present invention, a control method of a phase shifting device is provided, which is used to control the phase shifting device provided by any embodiment of the present invention; the control method of the phase shifting device comprises:

[0028] When the phase shift device operates normally, the number of phase shift branches that need to be put into use is determined according to the capacity demand of the power grid; the corresponding number of phase shift branches are controlled to be turned on, and the bypass branch is controlled to be turned off;

[0029] When a non-tripping fault occurs to some of the phase-shifting branches, the phase-shifting branches with the non-tripping fault are controlled to be disconnected, and other phase-shifting branches are controlled to be turned on according to the capacity demand of the power grid;

[0030] When a tripping fault occurs to at least one of the phase-shifting branches, the bypass branch and all the phase-shifting branches are controlled to be disconnected;

[0031] When some of the phase-shifting branches need to be repaired, the phase-shifting branches that need to be repaired are controlled to be disconnected, and other phase-shifting branches are controlled to be turned on according to the capacity demand of the power grid;

[0032] When all the phase-shifting branches need to be repaired, the bypass branch is controlled to be turned on, and all the phase-shifting branches are controlled to be turned off.

[0033] Optionally, controlling the phase shift branch to be turned on includes:

[0034] Controlling the first isolating switch and the second isolating switch to close;

[0035] controlling the first circuit breaker to close;

[0036] Controlling the phase-shift branch to be disconnected comprises:

[0037] Controlling the first circuit breaker to open;

[0038] The first isolating switch and the second isolating switch are controlled to be disconnected.

[0039] Optionally, controlling the bypass branch to be turned on includes:

[0040] Controlling the third isolating switch and the fourth isolating switch to be closed;

[0041] controlling the second circuit breaker to close;

[0042] Controlling the bypass branch to be disconnected includes:

[0043] controlling the second circuit breaker to open;

[0044] The third isolating switch and the fourth isolating switch are controlled to be opened.

[0045] In the phase-shifting device provided in the embodiment of the present invention, a plurality of phase-shifting branches and a bypass branch connected in parallel are provided. The system can determine the number of phase-shifting branches that need to be put into operation according to the capacity demand, so that the power grid flow is flexible and controllable, and the loss can be reduced. Compared with the single large-capacity phase-shifting transformer in the prior art, this embodiment adopts a plurality of phase-shifting transformers with smaller capacity to be connected in parallel to the system. Since the small-capacity phase-shifting transformer is small in size, the overall transportation difficulty and cost of the phase-shifting device can be reduced, and the installation positions of the plurality of phase-shifting transformers can be flexibly set according to the on-site environment without consuming a large area, which is conducive to the installation of the phase-shifting device. In addition, when some phase-shifting transformers need to be withdrawn from operation due to non-tripping faults or maintenance needs, other phase-shifting transformers can be put into operation, thereby avoiding the phase-shifting transformer withdrawing due to the above reasons and affecting the normal operation of the system, improving the system reliability, and making the equipment maintenance more flexible, convenient for maintenance, and enhancing the reliability. Furthermore, the setting of the bypass branch can ensure that the outgoing line does not shut down during the switching process of each phase-shifting branch, thereby ensuring the safe operation of the system and equipment; and in this embodiment, only one bypass branch is set, which can minimize the use of equipment, improve economic efficiency, and simplify the switching process. Therefore, compared with the prior art, the embodiment of the present invention can improve the safety and reliability of the power system and reduce the difficulty of transporting and installing the phase-shifting device.

[0046] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0048] Figure 1 is a structural schematic diagram of a phase shifting device provided by an embodiment of the present invention;

[0049] Figure 2 is a structural schematic diagram of a phase shift branch provided by an embodiment of the present invention;

[0050] Figure 3 is a schematic structural diagram of another phase shifting device provided by an embodiment of the present invention;

[0051] Figure 4 is a flow chart of a control method of a phase shifting device provided by an embodiment of the present invention;

[0052] Figure 5 It is a flow chart of another control method of a phase shifting device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0053] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0054] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0055] An embodiment of the present invention provides a phase shifting device. Figure 1 is a schematic diagram of the structure of a phase shifting device provided by an embodiment of the present invention. Figure 1 The phase shift device includes a first connection end 100 and a second connection end 200. When in use, the phase shift device is connected in series to the outgoing line of the substation. Exemplarily, the first connection end 100 of the phase shift device is close to the substation side and connected to the outgoing port of the substation, and the second connection end 200 is electrically connected to the receiving end of the outgoing line. Figure 1 The phase shifting device includes: a bypass branch 12 and at least two phase shifting branches 11; the bypass branch 12 and the phase shifting branch 11 are connected in parallel between the first connection end 100 and the second connection end 200.

[0056] The phase-shifting branch 11 includes: a first isolating switch DS1, a second isolating switch DS2, a first circuit breaker CB1 and a phase-shifting transformer 110; the first end of the first isolating switch DS1 is used as the first end of the phase-shifting branch 11 and is electrically connected to the first connection end 100 of the phase-shifting device; the second end of the second isolating switch DS2 is used as the second end of the phase-shifting branch 11 and is electrically connected to the second connection end 200 of the phase-shifting device; the first circuit breaker CB1 and the phase-shifting transformer 110 are connected in series between the second end of the first isolating switch DS1 and the first end of the second isolating switch DS2. The bypass branch 12 includes: a third isolating switch DS3, a fourth isolating switch DS4 and a second circuit breaker CB2; the first end of the third isolating switch DS3 is used as the first end of the bypass branch 12 and is electrically connected to the first connection end 100 of the phase-shifting device; the second end of the fourth isolating switch DS4 is used as the second end of the bypass branch and is electrically connected to the second connection end 200 of the phase-shifting device; the second circuit breaker CB2 is connected in series between the second end of the third isolating switch DS3 and the first end of the fourth isolating switch DS4.

[0057] Exemplarily, when the phase-shifting device is connected to the power system, by controlling the closing and opening of each isolating switch and circuit breaker in the phase-shifting device, it is possible to control whether the phase-shifting branch 11 and the bypass branch 12 are connected to the system. Specifically, by controlling the first isolating switch DS1, the second isolating switch DS2 and the first circuit breaker CB1 to be closed, the phase-shifting branch 11 can be turned on and connected to the system; by controlling the first isolating switch DS1, the second isolating switch DS2 and the first circuit breaker CB1 to be opened, the phase-shifting branch 11 can be disconnected and removed from the system; by controlling the third isolating switch DS3, the fourth isolating switch DS4 and the second circuit breaker CB2 to be closed, the bypass branch 12 can be turned on and connected to the system; by controlling the third isolating switch DS3, the fourth isolating switch DS4 and the second circuit breaker CB2 to be opened, the bypass branch 12 can be disconnected and removed from the system. In practical applications, the switching of the phase-shifting device can be controlled by the automatic control system of the power system, and can also be controlled manually when necessary.

[0058] Exemplarily, when the phase shifting device is in use, the control process thereof includes:

[0059] Initial state: the bypass branch 12 is controlled to be turned on, and all the phase-shift branches 11 are controlled to be turned off.

[0060] When all phase-shifting branches 11 have no faults: the number of phase-shifting branches 11 that need to be put into use is determined according to the capacity requirement of the system; the corresponding number of phase-shifting branches 11 are controlled to be turned on, and the bypass branches 12 are controlled to be turned off.

[0061] When some phase-shifting branches 11 have non-tripping faults or require maintenance, the phase-shifting branches 11 that have non-tripping faults or require maintenance are disconnected, and other normal phase-shifting branches 11 are put into use to meet the capacity requirements of the system. During the switching process of the phase-shifting branches 11, the bypass branch 12 can be turned on to ensure that the outgoing line does not stop power supply.

[0062] When the phase shifting device needs to be inspected and taken out of operation, the bypass branch 12 is controlled to be turned on, and all the phase shifting branches 11 are controlled to be turned off.

[0063] When a tripping fault occurs to at least one phase-shifting branch 11, such as a ground fault, the bypass branch 12 and all phase-shifting branches 11 are controlled to be disconnected, causing a power outage in the line.

[0064] In the phase-shifting device provided in the embodiment of the present invention, a plurality of phase-shifting branches 11 and a bypass branch 12 connected in parallel are provided. The system can determine the number of phase-shifting branches 11 to be put into operation according to the capacity demand, so that the power grid flow is flexible and controllable, and the loss can be reduced. Compared with a single large-capacity phase-shifting transformer in the prior art, this embodiment uses a plurality of phase-shifting transformers 110 with smaller capacity to be connected in parallel to the system. Since the small-capacity phase-shifting transformer 110 has a small volume, the overall transportation difficulty and cost of the phase-shifting device can be reduced. Secondly, the installation positions of the plurality of phase-shifting transformers 110 can be flexibly set according to the on-site environment without consuming a large area, which is conducive to the installation of the phase-shifting device. In addition, when some phase-shifting transformers 110 need to be withdrawn from operation due to non-tripping faults or maintenance needs, other phase-shifting transformers 110 can be put into operation, thereby avoiding the phase-shifting transformer 110 withdrawing due to the above reasons and affecting the normal operation of the system, improving the system reliability, and making the equipment maintenance more flexible, convenient for maintenance, and enhancing the reliability. Furthermore, the setting of the bypass branch 12 can ensure that the outgoing line does not shut down during the switching process of each phase-shifting branch 11, thereby ensuring the safe operation of the system and equipment; and in this embodiment, only one bypass branch 12 is set, which can minimize the use of equipment, improve economic efficiency, and simplify the switching process. Therefore, compared with the prior art, the embodiment of the present invention can improve the safety and reliability of the power system and reduce the difficulty of transporting and installing the phase-shifting device.

[0065] The above embodiments exemplarily provide the overall structure of the phase shifting device. Figure 2 , the specific structure of the phase shift branch 11 is described, but it is not intended to limit the present invention.

[0066] Figure 2 is a schematic diagram of the structure of a phase shift branch provided by an embodiment of the present invention. Figure 2In the phase-shifting branch 11, the phase-shifting transformer 110 serves as a flow control device in the phase-shifting branch 11; the first circuit breaker CB1 is used to disconnect when the phase-shifting transformer 110 fails or stops operating; the first isolating switch DS1 and the second isolating switch DS2 are used to disconnect when the phase-shifting transformer 110 fails or stops operating.

[0067] Continue to see Figure 2 In one embodiment, optionally, the phase-shifting transformer 110 includes: a series transformer T1 and a parallel transformer T2. The series transformer T1 includes a primary winding and a secondary winding, and the parallel transformer T2 includes a primary winding and a secondary winding. The primary winding of the series transformer T1 is connected in series in the phase-shifting branch 11. A first terminal is drawn out from the primary winding of the series transformer T1, and the first terminal is electrically connected to the primary winding of the parallel transformer T2; a second terminal is drawn out from the secondary winding of the series transformer T1, and the second terminal is electrically connected to the secondary winding of the parallel transformer T2. That is, the series transformer T1 and the parallel transformer T2 are connected via a larynx. It should be noted that, Figure 2 The figure only exemplarily shows the connection relationship between the series transformer T1 and the parallel transformer T2, and the actual connection can be set according to actual needs.

[0068] Continue to see Figure 2 On the basis of the above implementation, optionally, the primary winding of the series transformer T1 is directly connected in series in the phase-shifting branch, and the secondary winding of the series transformer T1 adopts a delta connection; the primary winding and the secondary winding of the parallel transformer T2 both adopt a star connection.

[0069] Continue to see Figure 2 On the basis of the above embodiment, optionally, the phase-shifting branch 11 further includes: a first lightning arrester SA1, a first grounding switch ES1, a second lightning arrester SA1 and a second grounding switch ES2. The first end of the first lightning arrester SA1 is electrically connected to the neutral point of the primary winding of the parallel transformer T2, and the second end of the first lightning arrester SA1 is grounded; the first end of the first grounding switch ES1 is electrically connected to the neutral point of the primary winding of the parallel transformer T1, and the second end of the first grounding switch ES1 is grounded. The first end of the second lightning arrester SA2 is electrically connected to the neutral point of the secondary winding of the parallel transformer T2, and the second end of the second lightning arrester SA2 is grounded; the first end of the second grounding switch ES2 is electrically connected to the neutral point of the secondary winding of the parallel transformer T2, and the second end of the second grounding switch ES2 is grounded. This arrangement is equivalent to installing grounding protection for the neutral point of the parallel transformer T2, which can prevent the transformer from being endangered when a grounding fault occurs or a resonant overvoltage occurs. Exemplarily, the neutral points of the two windings of the parallel transformer T2 can also be connected to a discharge gap as a protection device.

[0070] Continue to see Figure 2On the basis of the above embodiment, optionally, the phase-shifting branch 11 further includes: a third grounding switch ES3 and a fourth grounding switch ES4. The first end of the third grounding switch ES3 is electrically connected to the second end of the first isolating switch DS1, and the second end of the third grounding switch ES3 is grounded; the first end of the fourth grounding switch ES4 is electrically connected to the first end of the second isolating switch DS2, and the second end of the fourth grounding switch ES4 is grounded. The third grounding switch ES3 and the fourth grounding switch ES4 can be grounded when the phase-shifting branch 11 is overhauled or shut down to ensure the safety of relevant personnel.

[0071] Continue to see Figure 2 On the basis of the above embodiment, optionally, the phase-shifting branch 11 further includes: a first current transformer CT1 and a second current transformer CT2; the first current transformer CT1 and the second current transformer CT2 are both connected in series with the phase-shifting transformer 110, and the first current transformer CT1 and the second current transformer CT2 are respectively arranged on both sides of the phase-shifting transformer 110. The first current transformer CT1 and the second current transformer CT2 can detect the current of the phase-shifting branch 11 in real time, and provide a current measurement signal to the control system, and the control system can determine the operating state of the phase-shifting branch 11 according to the current measurement signal. Exemplarily, the phase-shifting branch 11 can also include a fourth current transformer CT4 and a fifth current transformer CT5, which are respectively connected to the neutral points of the two windings of the parallel transformer T2, and are used to detect the current of each winding of the parallel transformer T2.

[0072] Figure 3 It is a schematic structural diagram of another phase shifting device provided in an embodiment of the present invention. Figure 3 Two phase-shifting branches are given as an example, namely the first phase-shifting branch 11-1 and the second phase-shifting branch 11-2. The structures of the two phase-shifting branches are the same, and both can be referred to. Figure 2 The relevant descriptions are not repeated here. Figure 3 , the specific structure of the bypass branch 12 is explained.

[0073] See also Figure 3 In the bypass branch 12, the second circuit breaker CB2 is used to close when the phase-shifting branch 11 fails or stops operating, so that the line can operate through the bypass branch. The third isolating switch DS3 and the fourth isolating switch DS4 can remain closed and open when the second circuit breaker CB2 is overhauled or stopped operating.

[0074] Continue to see Figure 3On the basis of the above embodiments, optionally, the bypass branch 12 further includes: a fifth grounding switch ES5 and a sixth grounding switch ES6. The first end of the fifth grounding switch ES5 is electrically connected to the second end of the third isolating switch DS3, and the second end of the fifth grounding switch ES5 is grounded; the first end of the sixth grounding switch ES6 is electrically connected to the first end of the fourth isolating switch DS4, and the second end of the sixth grounding switch ES6 is grounded. The fifth grounding switch ES5 and the sixth grounding switch ES6 can be grounded when the bypass branch 12 is overhauled or shut down to ensure the safety of relevant personnel. Exemplarily, when the second connection end 200 is connected to the power receiving end of the outgoing line, the bypass branch 12 can also include a seventh grounding switch ES7, which is electrically connected to the second end of the fourth isolating switch DS4, so as to be grounded when the outgoing line is shut down for overhaul to ensure the safety of relevant personnel.

[0075] Continue to see Figure 3 On the basis of the above embodiments, optionally, the bypass branch 12 also includes: a third current transformer CT3, used to detect the current of the bypass branch 12; the third current transformer CT3 and the second circuit breaker CB2 are connected in series between the second end of the third isolating switch DS3 and the first end of the fourth isolating switch DS4.

[0076] Continue to see Figure 3 On the basis of the above embodiments, optionally, the phase shift device further includes: a fifth isolating switch DS5, a voltage transformer CVT and a third lightning arrester SA3. The first end of the fifth isolating switch DS5 is electrically connected to the second connection end 200 of the phase shift device, and the second end of the fifth isolating switch DS5 is electrically connected to the voltage transformer CVT; the first end of the third lightning arrester SA3 is electrically connected to the second connection end 200 of the phase shift device, and the second end of the third lightning arrester SA3 is grounded. The third lightning arrester SA3 is used to prevent various overvoltages from invading the substation and the series transformer. The voltage transformer CVT can be, for example, a capacitive voltage transformer, which is used to provide a voltage measurement signal to the control system. The control system can judge the operating state of the phase shift device according to the above-mentioned various current measurement signals, voltage measurement signals and the action states of each protection device.

[0077] The embodiment of the present invention further provides a control method of a phase shifting device, which is used to control the phase shifting device provided by any embodiment of the present invention, and has corresponding beneficial effects. The control method of the phase shifting device includes:

[0078] When the phase shift device operates normally, the number of phase shift branches that need to be put into use is determined according to the capacity demand of the power grid; the corresponding number of phase shift branches are controlled to be turned on, and the bypass branches are controlled to be disconnected.

[0079] When non-tripping faults occur in some phase-shifting branches, the phase-shifting branches where the non-tripping faults occur are controlled to be disconnected, and other phase-shifting branches are controlled to be turned on according to the capacity demand of the power grid.

[0080] When a tripping fault occurs in at least one phase-shifting branch, the bypass branch and all phase-shifting branches are controlled to be disconnected.

[0081] When some phase-shifting branches need to be repaired, the phase-shifting branches that need to be repaired are controlled to be disconnected, and other phase-shifting branches are controlled to be turned on according to the capacity demand of the power grid.

[0082] When all phase-shifting branches need to be repaired, the bypass branch is controlled to be turned on, and all phase-shifting branches are controlled to be turned off.

[0083] The operating status of each branch can be determined based on the measurement signals of each current transformer and voltage transformer connected to the phase shifting device.

[0084] On the basis of the above-mentioned embodiments, optionally, by reasonably configuring the switches of the phase shifting device and setting a reasonable switch operation sequence, the impact of the phase shifting device on the power system and the equipment itself during the process of connecting to the system can be minimized, and the power supply reliability can be guaranteed while the bypass branch is set.

[0085] Specifically, controlling the phase-shift branch to be turned on includes: first controlling the first isolating switch and the second isolating switch to be closed; and then controlling the first circuit breaker to be closed. Controlling the phase-shift branch to be turned off includes: first controlling the first circuit breaker to be turned off; and then controlling the first isolating switch and the second isolating switch to be turned off. Controlling the bypass branch to be turned on includes: first controlling the third isolating switch and the fourth isolating switch to be closed; and then controlling the second circuit breaker to be closed. Controlling the bypass branch to be turned off includes: first controlling the second circuit breaker to be turned off; and then controlling the third isolating switch and the fourth isolating switch to be turned off.

[0086] Combine the following Figure 3 With reference to the specific structure of the embodiment, taking the phase shifting device including two phase shifting branches as an example, the action sequence of each switch in the phase shifting device in each case is explained.

[0087] Figure 4 FIG. 1 is a flow chart of a control method of a phase shifting device provided by an embodiment of the present invention. Figure 3 and Figure 4 When the line flow passes through the bypass branch 12, if the two phase-shifting branches are to be put into use, it is necessary to perform multiple switch switching operations on the two phase-shifting branches and the bypass branch. The specific operation steps are as follows:

[0088] S110, close the first isolating switch DS1-1 in the first phase-shifting branch 11-1.

[0089] S120, close the second isolating switch DS2-1 in the first phase-shifting branch 11-1.

[0090] S130, close the first isolating switch DS1-2 in the second phase-shifting branch 11-2.

[0091] S140, close the second isolating switch DS2-2 in the second phase-shifting branch 11-2.

[0092] S150, close the first circuit breaker CB1-1 in the first phase-shifting branch 11-1 and the first circuit breaker CB1-2 in the second phase-shifting branch 11-2.

[0093] When the first circuit breaker CB1-1 in the first phase-shifting branch 11-1 and the first circuit breaker CB1-2 in the second phase-shifting branch 11-2 are not closed at the same time, the impact of the phase-shifting device on the power grid can be further reduced.

[0094] S160 , disconnect the second circuit breaker CB2 in the bypass branch 12 .

[0095] When only one phase-shifting transformer is required to operate, only the first circuit breaker in the phase-shifting branch may be closed in S150.

[0096] Continue to see Figure 3 When the first phase-shifting transformer 110-1 or the second phase-shifting transformer 110-2 has a non-tripping fault or needs maintenance, the other phase-shifting transformer can still operate independently. At this time, the faulty phase-shifting transformer can be cut off through the following operations without affecting the normal operation of the other phase-shifting branch.

[0097] If the first phase-shifting transformer 110-1 has a non-tripping fault or needs maintenance, the specific operation steps are as follows:

[0098] Disconnect the first circuit breaker CB1-1 in the first phase-shifting branch 11-1;

[0099] Disconnect the first isolating switch DS1-1 in the first phase-shifting branch 11-1;

[0100] The second isolating switch DS2-1 in the first phase-shifting branch 11-1 is disconnected.

[0101] If the second phase-shifting transformer 110-2 has a non-tripping fault or needs maintenance, the specific operation steps are as follows:

[0102] Disconnect the first circuit breaker CB1-2 in the second phase-shifting branch 11-2;

[0103] Disconnect the first isolating switch DS1-2 in the second phase-shifting branch 11-2;

[0104] The second isolating switch DS2-2 in the second phase-shifting branch 11-2 is disconnected.

[0105] Continue to see Figure 3 When any phase-shifting transformer has a tripping fault, such as a grounding fault, a phase-to-phase short-circuit fault, etc., the line will be affected by the short-circuit fault of the phase-shifting device and need to be shut down.

[0106] Figure 5 FIG. 1 is a flow chart of another control method of a phase shifting device provided by an embodiment of the present invention. Figure 3 and Figure 5 When the line flow is running normally through the two phase-shifting transformers, if the two phase-shifting branches need to be repaired and shut down, the line flow needs to be re-transferred to the bypass branch 12. The specific operation steps are as follows:

[0107] S210 , close the second circuit breaker CB2 in the bypass branch 12 .

[0108] S220 , disconnect the first circuit breaker CB1 - 1 in the first phase-shifting branch 11 - 1 and the first circuit breaker CB1 - 2 in the second phase-shifting branch 11 - 2 .

[0109] S230, disconnect the second isolating switch DS2-1 in the first phase-shifting branch 11-1.

[0110] S240, disconnect the first isolating switch DS1-1 in the first phase-shifting branch 11-1.

[0111] S250, disconnect the second isolating switch DS2-2 in the second phase-shifting branch 11-2.

[0112] S260. Disconnect the first isolating switch DS1-2 in the second phase-shifting branch 11-2.

[0113] When only one phase-shifting transformer is in operation, only the first circuit breaker in the phase-shifting branch may be disconnected in S250.

[0114] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0115] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A phase shifting device, characterized in that: The phase shifting device is connected in series to the outgoing line of the substation; The phase shifting device comprises: a bypass branch and at least two phase shifting branches; the bypass branch and the phase shifting branch are connected in parallel; The phase-shifting branch comprises: a first isolating switch, a second isolating switch, a first circuit breaker and a phase-shifting transformer; a first end of the first isolating switch is electrically connected to a first connection end of the phase-shifting device; a second end of the second isolating switch is electrically connected to a second connection end of the phase-shifting device; the first circuit breaker and the phase-shifting transformer are connected in series between the second end of the first isolating switch and the first end of the second isolating switch; The bypass branch includes: a third isolating switch, a fourth isolating switch and a second circuit breaker; the first end of the third isolating switch is electrically connected to the first connection end of the phase shifting device; the second end of the fourth isolating switch is electrically connected to the second connection end of the phase shifting device; the second circuit breaker is connected in series between the second end of the third isolating switch and the first end of the fourth isolating switch; The phase-shifting transformer includes: a series transformer and a parallel transformer; wherein the series transformer includes a primary winding and a secondary winding, and the parallel transformer includes a primary winding and a secondary winding; The primary winding of the series transformer is connected in series in the phase-shifting branch; a first terminal is led out from the primary winding of the series transformer, and the first terminal is electrically connected to the primary winding of the parallel transformer; a second terminal is led out from the secondary winding of the series transformer, and the second terminal is electrically connected to the secondary winding of the parallel transformer; The primary winding of the series transformer is directly connected in series in the phase-shifting branch, and the secondary winding of the series transformer adopts a delta connection method; The primary winding and the secondary winding of the parallel transformer are both connected in star shape.

2. The phase shifting device according to claim 1, characterized in that: The phase shift branch also includes: A first lightning arrester, wherein a first end of the first lightning arrester is electrically connected to a neutral point of a primary winding of the shunt transformer, and a second end of the first lightning arrester is grounded; a first grounding switch, wherein a first end of the first grounding switch is electrically connected to a neutral point of a primary winding of the shunt transformer, and a second end of the first grounding switch is grounded; a second lightning arrester, wherein a first end of the second lightning arrester is electrically connected to a neutral point of a secondary winding of the shunt transformer, and a second end of the second lightning arrester is grounded; A second grounding switch, wherein a first end of the second grounding switch is electrically connected to a neutral point of the secondary winding of the parallel transformer, and a second end of the second grounding switch is grounded.

3. The phase shifting device according to claim 1, characterized in that: The phase shift branch also includes: a third grounding switch; a first end of the third grounding switch is electrically connected to a second end of the first isolating switch, and a second end of the third grounding switch is grounded; a fourth grounding switch; a first end of the fourth grounding switch is electrically connected to a first end of the second isolating switch, and a second end of the fourth grounding switch is grounded; The bypass branch also includes: a fifth grounding switch; a first end of the fifth grounding switch is electrically connected to a second end of the third isolating switch, and a second end of the fifth grounding switch is grounded; a sixth grounding switch; a first end of the sixth grounding switch is electrically connected to the first end of the fourth isolating switch, and a second end of the sixth grounding switch is grounded.

4. The phase shifting device according to claim 1, characterized in that: The phase-shifting branch further includes: a first current transformer and a second current transformer; the first current transformer and the second current transformer are both connected in series with the phase-shifting transformer, and the first current transformer and the second current transformer are respectively arranged on both sides of the phase-shifting transformer; The bypass branch further includes: a third current transformer; the third current transformer and the second circuit breaker are connected in series between the second end of the third isolating switch and the first end of the fourth isolating switch.

5. The phase shifting device according to claim 1, characterized in that: Also includes: the fifth isolating switch, the voltage transformer and the third lightning arrester; The first end of the fifth isolating switch is electrically connected to the second connection end of the phase shifting device, and the second end of the fifth isolating switch is electrically connected to the voltage transformer; the first end of the third lightning arrester is electrically connected to the second connection end of the phase shifting device, and the second end of the third lightning arrester is grounded.

6. A control method for a phase shifting device, characterized in that: Used to control the phase shifting device according to any one of claims 1 to 5; The control method of the phase shifting device comprises: When the phase shift device operates normally, the number of phase shift branches that need to be put into use is determined according to the capacity demand of the power grid; the corresponding number of phase shift branches are controlled to be turned on, and the bypass branch is controlled to be turned off; When a non-tripping fault occurs to some of the phase-shifting branches, the phase-shifting branches with the non-tripping fault are controlled to be disconnected, and other phase-shifting branches are controlled to be turned on according to the capacity demand of the power grid; When a tripping fault occurs to at least one of the phase-shifting branches, the bypass branch and all the phase-shifting branches are controlled to be disconnected; When some of the phase-shifting branches need to be repaired, the phase-shifting branches that need to be repaired are controlled to be disconnected, and other phase-shifting branches are controlled to be turned on according to the capacity demand of the power grid; When all the phase-shifting branches need to be repaired, the bypass branch is controlled to be turned on, and all the phase-shifting branches are controlled to be turned off.

7. The control method of the phase shifting device according to claim 6, characterized in that: Controlling the conduction of the phase-shift branch includes: Controlling the first isolating switch and the second isolating switch to close; controlling the first circuit breaker to close; Controlling the phase-shift branch to be disconnected comprises: Controlling the first circuit breaker to open; The first isolating switch and the second isolating switch are controlled to be disconnected.

8. The control method of the phase shifting device according to claim 6, characterized in that: Controlling the conduction of the bypass branch includes: Controlling the third isolating switch and the fourth isolating switch to be closed; controlling the second circuit breaker to close; Controlling the bypass branch to be disconnected includes: controlling the second circuit breaker to open; The third isolating switch and the fourth isolating switch are controlled to be opened.

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