CN114221325A - Method for automatically adjusting three-phase unbalanced load of distribution transformer - Google Patents
Method for automatically adjusting three-phase unbalanced load of distribution transformer Download PDFInfo
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- CN114221325A CN114221325A CN202111345077.9A CN202111345077A CN114221325A CN 114221325 A CN114221325 A CN 114221325A CN 202111345077 A CN202111345077 A CN 202111345077A CN 114221325 A CN114221325 A CN 114221325A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/26—Arrangements for eliminating or reducing asymmetry in polyphase networks
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/007—Arrangements for selectively connecting the load or loads to one or several among a plurality of power lines or power sources
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/007—Arrangements for selectively connecting the load or loads to one or several among a plurality of power lines or power sources
- H02J3/0073—Arrangements for selectively connecting the load or loads to one or several among a plurality of power lines or power sources for providing alternative feeding paths between load and source when the main path fails, e.g. transformers, busbars
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/007—Arrangements for selectively connecting the load or loads to one or several among a plurality of power lines or power sources
- H02J3/0075—Arrangements for selectively connecting the load or loads to one or several among a plurality of power lines or power sources for providing alternative feeding paths between load and source according to economic or energy efficiency considerations, e.g. economic dispatch
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/12—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/12—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load
- H02J3/14—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load by switching loads on to, or off from, network, e.g. progressively balanced loading
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/12—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load
- H02J3/14—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load by switching loads on to, or off from, network, e.g. progressively balanced loading
- H02J3/144—Demand-response operation of the power transmission or distribution network
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/30—Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
- Y02B70/3225—Demand response systems, e.g. load shedding, peak shaving
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/50—Arrangements for eliminating or reducing asymmetry in polyphase networks
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S20/00—Management or operation of end-user stationary applications or the last stages of power distribution; Controlling, monitoring or operating thereof
- Y04S20/20—End-user application control systems
- Y04S20/222—Demand response systems, e.g. load shedding, peak shaving
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Supply And Distribution Of Alternating Current (AREA)
Abstract
The invention discloses a method for automatically adjusting three-phase unbalanced load of a distribution transformer, which solves the problem of unbalanced load of the distribution transformer caused by construction operation on a power utilization side or sudden increase of the power utilization load and the like. The method comprises the following steps: the monitoring device is used for acquiring the amplitude and the phase angle of three-phase voltage on the load side of the distribution transformer, a controllable switch is configured at the joint of each load side line and a power supply, non-important users are distinguished in advance and are uniformly connected to a specified load line, and the three-phase unbalanced load of the distribution transformer is automatically adjusted by adopting the modes of single-phase grid connection with the distribution transformer in an adjacent transformer area, switching of the phase of the load of a public facility, automatic removal of the non-important load and the like.
Description
Technical Field
The invention relates to a method for automatically adjusting three-phase unbalanced load of a distribution transformer, belonging to the field of power distribution.
Background
Distribution transformers are power supply equipment installed in social places such as residential buildings, streets and communities by power supply companies, and are used for reducing high-level voltage on a power transmission line to low-level voltage for residents and public facilities. The area in charge of the distribution transformer is called a transformer area, and if the distribution transformer in a certain transformer area is stopped due to abnormal conditions such as maintenance or faults, the power failure of users and shared facilities in the transformer area can be caused.
Due to the fact that construction operation or sudden increase of the power load and the like occur on the power utilization side, the load of one phase or two phases of three phases of the distribution transformer can be increased, three phases are unbalanced, the load of the distribution transformer is unbalanced, and the distribution transformer is damaged or the power supply quality of users in the distribution area is reduced in serious conditions.
When the distribution transformer is in an unbalanced load condition, the conventional treatment mode is to adjust the three-phase sequence after the distribution transformer is stopped, and all users and public facilities in the distribution area are powered off under the condition. With the increasing demand of power consumption in society year by year, users in the transformer area which is responsible for each distribution transformer are more complex and diversified, and in order to ensure the continuity and reliability of power supply and reduce complaints of the users to power supply companies, the conventional method is not suitable for solving the problems.
Disclosure of Invention
The invention provides a method for automatically adjusting three-phase unbalanced load of a distribution transformer. The monitoring device is used for acquiring the amplitude and the phase angle of three-phase voltage on the load side of the distribution transformer, a controllable switch is configured at the joint of each load side line and a power supply, and the three-phase unbalanced load of the distribution transformer is automatically adjusted by adopting the modes of single-phase grid connection with the distribution transformer in the adjacent distribution area, switching of the phase of the load of the public facility, automatic removal of unimportant load and the like.
The technical scheme of the invention is as follows: a method for automatically adjusting three-phase unbalanced load of a distribution transformer comprises the following steps:
step 1, in a distribution transformer area, a distribution transformer is used for providing a three-phase alternating current power supply for a distribution bus, the distribution bus is 3 conductive copper rods configured according to required specifications, any one of the distribution bus is connected with the A-phase alternating current output of the distribution transformer to form an A-phase distribution bus, and the other two distribution buses are a B-phase distribution bus and a C-phase distribution bus in sequence;
and 2, using a power switch to control the on or off of the power supply, wherein the power switch has two states of switching off and switching on, and one end of the power switch is defined as a power side and the other end of the power switch is defined as a load side according to the directions of the power supply and the load. The power switch comprises an A-phase power switch, a B-phase power switch, a C-phase power switch, a first public switch, a second public switch, a third public switch, a first secondary user switch, a second secondary user switch, a third secondary user switch and a plurality of branch switches;
step 3, the power switches are all provided with a data acquisition and control device for monitoring the running state of the power switches, and the data acquisition and control device monitors the current of the monitored branch by using a first measurement loop; the data acquisition and control device controls a first node to excite a power switch closing relay through closing the data acquisition and control device, and then the switch of the monitored branch is controlled to be closed; and the data acquisition and control device controls the node II to excite the power switch opening relay by closing the data acquisition and control device, so as to control the switch opening of the monitored branch. The power supply of the data acquisition and control device is taken from a load side circuit where the power switch is positioned;
step 4, in the transformer area I, a first distribution transformer is used for providing a three-phase alternating-current power supply for a first distribution bus, and an A-phase distribution bus I is used for connecting power supply sides of a first zone-branch switch 1-1, a first zone-branch switch 1-2 and a … … first zone-branch switch 1-N through power cables; connecting a power supply side of a distribution area-branch switch 2-1, a distribution area-branch switch 2-2 and a … … distribution area-branch switch 2-N by using a B-phase distribution bus I through a power cable; connecting the power supply side of a station-area-branch switch 3-1, a station-area-branch switch 3-2 and … … a station-area-branch switch 3-N by using a C-phase distribution bus I through a power cable, wherein the load side of the switches is sequentially connected to a load side circuit 1 and a load side circuit 2 … … load side circuit N through the power cable;
step 5, in the platform area I, uniformly connecting non-residential electricity consumption of public facilities and the like to a same load side circuit, namely a public facility load circuit, wherein the public facility load circuit is respectively connected to load sides of a public switch I, a public switch II and a public switch III through power cables, and power supply sides of the public switch I, the public switch II and the public switch III are sequentially connected with a matching electric bus A, a matching electric bus B and a matching electric bus C through the power cables;
step 6, in the station area I, equally dividing the secondary users into three parts, namely a primary secondary user, a secondary user and a tertiary secondary user, wherein any one part is connected to the load side of the primary secondary user switch through a power cable, the other two parts are respectively connected to the load sides of the secondary switch II and the secondary switch III, and the power supply sides of the primary secondary user switch I, the secondary user switch II and the secondary user switch III and the power cable are sequentially connected with a first matching power bus, a first matching power bus and a first matching power bus;
step 7, in a station area II adjacent to the station area I, a distribution transformer II is used for providing a three-phase alternating-current power supply for a distribution bus II, and an A-phase distribution bus I is used for connecting power supply sides of a station area two-branch switch 1-1, a station area two-branch switch 1-2 and … … station area two-branch switches 1-N through power cables; connecting a power supply side of a transformer area two-branch switch 2-1, a transformer area two-branch switch 2-2 and an … … transformer area two-branch switch 2-N by using a B-phase distribution bus I through a power cable; connecting a power supply side of a platform area two-branch switch 3-1, a platform area two-branch switch 3-2 and a … … platform area two-branch switch 3-N through a power cable by using a C-shaped matching bus II, wherein a load side of the switches is connected to a load side circuit through the power cable;
step 8, connecting any one end of the phase A power switch with the phase A matching electric bus I through a power cable, and connecting the other end of the phase A power switch with the phase A matching electric bus II through the power cable; connecting any end of the B-phase power switch with a first B-phase matching electric bus through a power cable, and connecting the other end of the B-phase power switch with a second B-phase matching electric bus through a power cable; connecting any end of the C-phase power switch with a first D-phase matching electrical bus through a power cable, and connecting the other end of the C-phase power switch with a second D-phase matching electrical bus through a power cable;
step 9, installing a distribution bus automatic switching device in the station area I, wherein the distribution bus automatic switching device monitors the voltage amplitude and the phase angle of a first phase of a distribution bus, a first phase of the distribution bus, a first phase C of the distribution bus, a second phase A of the distribution bus, a second phase B of the distribution bus and a second phase C of the distribution bus by using a constructed measurement loop II; the automatic switching device of the distribution bus controls the switching-on of the A-phase power switch, the B-phase power switch and the C-phase power switch through the built switching-on control loop, and controls the switching-off of all branch switches in the local area through the built switching-off control loop.
Further:
when the automatic switching device of the distribution bus detects that the sum of the voltage vectors of the first phase of the distribution bus, the first phase of the distribution bus and the second phase of the distribution bus is greater than a set value, the phase with the lowest voltage and the phase with the highest voltage are judged by the second measuring loop. Considering the actual situation when the distribution transformer begins to have unbalance loading, the set value is generally greater than 3 volts and less than or equal to 5 volts. If the lowest phase is the first phase B of the distribution bus and the highest phase is the first phase A of the distribution bus, the amplitude and the phase angle of the voltage of the second phase B of the distribution bus in the second distribution area are measured through the second measuring loop. And comparing the amplitude and the phase angle of the phase voltage of the first B phase of the distribution bus with the phase voltage of the second B phase of the distribution bus, and controlling the switch-on of the phase-B power switch through the automatic switching device of the distribution bus if the amplitude difference is smaller than the set value and the phase angle is smaller than the set value. The second setting value is generally not greater than 15 degrees, taking into account the minimum allowable range of the distribution busbar connections.
When the automatic switching device of the distribution bus detects that the sum of the voltage vectors of the first phase of the distribution bus, the second phase of the distribution bus and the first phase of the distribution bus is greater than the set value III, the phase with the lowest voltage and the phase with the highest voltage are judged by the measuring circuit II. If the lowest phase is the first phase B of the distribution bus and the highest phase is the first phase A of the distribution bus, detecting whether the second public switch is at the switching-on position or not through a data acquisition and control device, if so, switching off the second public switch through an automatic switching device of the distribution bus, and switching on the first public switch through the automatic switching device of the distribution bus within the time of a set value four after switching off. The third setting is generally greater than 5 volts and less than or equal to 10 volts, taking into account the degree of the distribution bus unbalance loading condition. Considering the influence of the instantaneous power failure on the user, the set value four is generally not more than 2 seconds.
When the automatic switching device of the distribution bus detects that the sum of the voltage vectors of the first phase A of the distribution bus, the first phase B of the distribution bus and the first phase C of the distribution bus is greater than a set value five, the phase with the lowest voltage and the phase with the highest voltage are judged by the second measuring loop. And if the lowest phase is the first phase B of the distribution bus and the highest phase is the first phase A of the distribution bus, the secondary user switch is switched off by the automatic switching device of the distribution bus. The set value five is generally greater than 10 volts and less than or equal to 15 volts, taking into account the degree of the distribution bus unbalance loading condition.
The invention has the beneficial effects that:
1. the automatic switching device of the distribution bus is used for automatically detecting the vector sum of the phase voltages of the A phase, the B phase and the C phase of the distribution bus, when the vector sum is larger than a set value, the phase difference with the lowest voltage and the highest voltage and the phase voltage value of each phase of the distribution bus of the adjacent distribution area can be judged, the distribution bus with the obvious voltage reduction of the distribution area is connected with the distribution bus of the adjacent distribution area by comparing the amplitude value and the phase angle of the corresponding phase voltage of the distribution bus of the adjacent distribution area, and the unbalanced load condition of a transformer of the distribution area is solved. Meanwhile, after the method is applied, when the distribution transformer in the local area or the adjacent area has a fault or is overhauled, part of the load can be transferred from the distribution bus of the non-fault or overhauled area, and the power failure range is further reduced.
2. Non-residential electricity utilization such as utilities in the distribution area is connected to the same load side line in a unified manner, and the lines are connected to A, B, C phase distribution buses of the distribution area. In this way, when the transformer in the distribution area has an unbalanced load condition, the condition of adjusting the three-phase unbalanced load of the distribution transformer can be achieved by switching the non-residential electricity from the phase with lower voltage to the phase with higher voltage, and the continuous and reliable power supply for users is ensured.
3. When the transformer unbalance loading condition in the transformer area is serious, the line power switch corresponding to the non-important user can be automatically cut according to the preset important user grade, and the power utilization quality and reliability of other important power utilization customers are ensured.
Drawings
FIG. 1 is a circuit wiring diagram of the present invention;
FIG. 2 is an electrical schematic of a measurement circuit;
FIG. 3 is an electrical schematic diagram of a measurement circuit two;
FIG. 4 is an electrical schematic diagram of a closing control loop;
FIG. 5 is an electrical schematic diagram of the opening control loop;
fig. 6 is a schematic diagram of an automatic switching device for a distribution bus.
Detailed Description
For the purpose of facilitating an understanding of the present invention, the present invention will be described in detail with reference to the following specific examples:
the invention relates to a method for automatically adjusting three-phase unbalanced load of a distribution transformer, which comprises the following steps:
step 1, in a distribution transformer area, a distribution transformer is used for providing a three-phase alternating current power supply for a distribution bus, the distribution bus is 3 conductive copper rods configured according to required specifications, any one of the distribution bus is connected with the A-phase alternating current output of the distribution transformer to form an A-phase distribution bus, and the other two distribution buses are a B-phase distribution bus and a C-phase distribution bus (as shown in figure 1);
and 2, using a power switch to control the on or off of the power supply, wherein the power switch has two states of switching off and switching on, and one end of the power switch is defined as a power side and the other end of the power switch is defined as a load side according to the directions of the power supply and the load. The power switch comprises an A-phase power switch, a B-phase power switch, a C-phase power switch, a first public switch, a second public switch, a third public switch, a first secondary user switch, a second secondary user switch, a third secondary user switch and a plurality of branch switches;
step 3, the power switches are all provided with a data acquisition and control device for monitoring the running state of the power switches, and the data acquisition and control device monitors the current of the monitored branch by using a measurement loop I (as shown in figure 2); the data acquisition and control device controls a first node to excite a power switch closing relay by closing the data acquisition and control device, and further controls the switch closing of the monitored branch (as shown in figure 4); the data acquisition and control device controls the node two to excite the power switch opening relay by closing the data acquisition and control device, and further controls the switch opening of the monitored branch (as shown in fig. 5). The power supply of the data acquisition and control device is taken from a load side circuit where the power switch is positioned;
step 4, in the transformer area I, a first distribution transformer is used for providing a three-phase alternating-current power supply for a first distribution bus, and an A-phase distribution bus I is used for connecting power supply sides of a first zone-branch switch 1-1, a first zone-branch switch 1-2 and a … … first zone-branch switch 1-N through power cables; connecting a power supply side of a distribution area-branch switch 2-1, a distribution area-branch switch 2-2 and a … … distribution area-branch switch 2-N by using a B-phase distribution bus I through a power cable; connecting the power supply side of a station-area-branch switch 3-1, a station-area-branch switch 3-2 and … … a station-area-branch switch 3-N by using a C-phase distribution bus I through a power cable, wherein the load side of the switches is sequentially connected to a load side circuit 1 and a load side circuit 2 … … load side circuit N through the power cable;
step 5, in the platform area I, uniformly connecting non-residential electricity consumption of public facilities and the like to a same load side circuit, namely a public facility load circuit, wherein the public facility load circuit is respectively connected to load sides of a public switch I, a public switch II and a public switch III through power cables, and power supply sides of the public switch I, the public switch II and the public switch III are sequentially connected with a matching electric bus A, a matching electric bus B and a matching electric bus C through the power cables;
step 6, in the station area I, equally dividing the secondary users into three parts, namely a primary secondary user, a secondary user and a tertiary secondary user, wherein any one part is connected to the load side of the primary secondary user switch through a power cable, the other two parts are respectively connected to the load sides of the secondary switch II and the secondary switch III, and the power supply sides of the primary secondary user switch I, the secondary user switch II and the secondary user switch III and the power cable are sequentially connected with a first matching power bus, a first matching power bus and a first matching power bus;
step 7, in a station area II adjacent to the station area I, a distribution transformer II is used for providing a three-phase alternating-current power supply for a distribution bus II, and an A-phase distribution bus I is used for connecting power supply sides of a station area two-branch switch 1-1, a station area two-branch switch 1-2 and … … station area two-branch switches 1-N through power cables; connecting a power supply side of a transformer area two-branch switch 2-1, a transformer area two-branch switch 2-2 and an … … transformer area two-branch switch 2-N by using a B-phase distribution bus I through a power cable; connecting a power supply side of a platform area two-branch switch 3-1, a platform area two-branch switch 3-2 and a … … platform area two-branch switch 3-N through a power cable by using a C-shaped matching bus II, wherein a load side of the switches is connected to a load side circuit through the power cable;
step 8, connecting any one end of the phase A power switch with the phase A matching electric bus I through a power cable, and connecting the other end of the phase A power switch with the phase A matching electric bus II through the power cable; connecting any end of the B-phase power switch with a first B-phase matching electric bus through a power cable, and connecting the other end of the B-phase power switch with a second B-phase matching electric bus through a power cable; connecting any end of the C-phase power switch with a first D-phase matching electrical bus through a power cable, and connecting the other end of the C-phase power switch with a second D-phase matching electrical bus through a power cable;
step 9, installing a distribution bus automatic switching device in the distribution area I, wherein the distribution bus automatic switching device monitors the voltage amplitude and the phase angle of a distribution bus I A phase, a distribution bus I B phase, a distribution bus I C phase and a distribution bus II A phase, a distribution bus II B phase and a distribution bus II C phase (as shown in figure 3) by using a constructed measurement loop II; the automatic switching device of the distribution bus controls the switching-on of the phase-A power switch, the phase-B power switch and the phase-C power switch through the built switching-on control loop, and controls the switching-off of all branch switches in the local area through the built switching-off control loop (as shown in fig. 6).
Application example:
in a 10 kV purple-slush line area, a first distribution transformer is used for providing a three-phase alternating-current power supply for a first distribution bus, and a first A-phase distribution bus is connected with 10 lines such as a purple east line, a purple white line and the like in the 10 kV purple-slush line area through a power cable; a B-phase distribution bus I is connected with 10 lines such as an east line, a white line and the like in a 10-kilovolt purple line area through a power cable; a C-phase distribution bus I is used for connecting 10 lines such as a Hudong line, a lake white line and the like in a 10 kV purple-Rabdosia line area through a power cable;
in a 10 kV purple diamond line area, the power utilization of a shed, the power utilization of an acoustic control lamp and the power utilization of square illumination are uniformly supplied by using a public facility line, and the public facility line is sequentially connected to an A phase distribution bus, a B phase distribution bus and a C phase distribution bus of the 10 kV purple diamond line area through a public switch I, a public switch II and a public switch III;
in a 10 KV purple-white line area, purple white lines, white lines and lake white lines are sequentially a first secondary user, a second secondary user and a third secondary user;
the 10 kV suburb line area is an adjacent area of the 10 kV purple-diamond line area. The A matched electric bus of the 10 kV violet ray transformer area is connected with the A matched electric bus of the 10 kV violet ray through an A-phase power switch; the B-phase matching electric bus of the 10 kV violet ray transformer area is connected with the B-phase matching electric bus of the 10 kV violet ray through a B-phase power switch; the C-phase matching electric bus of the 10 kV violet ray transformer area is connected with the C-phase matching electric bus of the 10 kV violet ray through a C-phase power switch;
when the B-phase unbalance loading condition occurs to the distribution transformer in the 10 kV purple-diamond line distribution area. The automatic switching device of the distribution bus starts to detect, and the sum of the voltage vectors of the phase A, the phase B and the phase C of the distribution bus in the 10 kV purple-slush line transformer area is equal to 4V, the lowest phase is the phase B of the distribution bus, the highest phase is the phase A of the distribution bus, and the amplitude phase difference between the phase B of the 10 kV purple-slush line distribution bus and the phase B of the 10 kV south-suburb line distribution bus is 4V and the phase angle difference is 10 degrees. At the moment, a B-phase power switch is controlled to be switched on through the automatic switching device of the distribution bus, and a B phase of a 10 kV purple-ice line distribution bus and a B phase of a 10 kV suburb line distribution bus are connected;
when the B-phase unbalance loading condition occurs to the distribution transformer in the 10 kV purple-diamond line distribution area. The automatic switching device of the distribution bus starts to detect, the sum of the voltage vectors of the phase A, the phase B and the phase C of the distribution bus in the 10 kV purple-slush line transformer area is equal to 6V, the lowest phase is the phase B of the distribution bus, the highest phase is the phase A of the distribution bus, and the public switch II is at the switching-on position. At the moment, the second public switch is switched off through the automatic switching device of the distribution bus, the first public switch is switched on through the automatic switching device of the distribution bus within 2 seconds after the second public switch is switched off, and a public facility line consisting of the electricity consumption of a shed, the electricity consumption of an acoustic control lamp and the electricity consumption of square illumination is switched from a 10 kilovolt violet ray line B to a 10 kilovolt violet ray line A to supply power.
When the B-phase unbalance loading condition occurs to the distribution transformer in the 10 kV purple-diamond line distribution area. The automatic switching device of the distribution bus starts to detect, the sum of the voltage vectors of the phase A, the phase B and the phase C of the distribution bus in the 10 kV purple-slush line transformer area is equal to 12V, the lowest phase is the phase B of the distribution bus, and the highest phase is the phase A of the distribution bus. At the moment, the secondary user switch is switched off through the automatic switching device of the distribution bus, and the secondary users in the 10 kV purple-diamond line area are cut off, namely, the purple-white line is cut off, so that the B-phase offset load condition of the distribution transformer in the 10 kV purple-diamond line area is further relieved.
The above description is only exemplary of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (2)
1. A method for automatically adjusting three-phase unbalanced load of a distribution transformer is characterized by comprising the following steps:
step 1, in a distribution transformer area, a distribution transformer is used for providing a three-phase alternating current power supply for a distribution bus, the distribution bus is 3 conductive copper rods configured according to required specifications, any one of the distribution bus is connected with the A-phase alternating current output of the distribution transformer to form an A-phase distribution bus, and the other two distribution buses are a B-phase distribution bus and a C-phase distribution bus in sequence;
and 2, using a power switch to control the on or off of the power supply, wherein the power switch has two states of switching off and switching on, and one end of the power switch is defined as a power side and the other end of the power switch is defined as a load side according to the directions of the power supply and the load. The power switch comprises an A-phase power switch, a B-phase power switch, a C-phase power switch, a first public switch, a second public switch, a third public switch, a first secondary user switch, a second secondary user switch, a third secondary user switch and a plurality of branch switches;
step 3, the power switches are all provided with a data acquisition and control device for monitoring the running state of the power switches, and the data acquisition and control device monitors the current of the monitored branch by using a first measurement loop; the data acquisition and control device controls a first node to excite a power switch closing relay through closing the data acquisition and control device, and then the switch of the monitored branch is controlled to be closed; and the data acquisition and control device controls the node II to excite the power switch opening relay by closing the data acquisition and control device, so as to control the switch opening of the monitored branch. The power supply of the data acquisition and control device is taken from a load side circuit where the power switch is positioned;
step 4, in the transformer area I, a first distribution transformer is used for providing a three-phase alternating-current power supply for a first distribution bus, and an A-phase distribution bus I is used for connecting power supply sides of a first zone-branch switch 1-1, a first zone-branch switch 1-2 and a … … first zone-branch switch 1-N through power cables; connecting a power supply side of a distribution area-branch switch 2-1, a distribution area-branch switch 2-2 and a … … distribution area-branch switch 2-N by using a B-phase distribution bus I through a power cable; connecting the power supply side of a station-area-branch switch 3-1, a station-area-branch switch 3-2 and … … a station-area-branch switch 3-N by using a C-phase distribution bus I through a power cable, wherein the load side of the switches is sequentially connected to a load side circuit 1 and a load side circuit 2 … … load side circuit N through the power cable;
step 5, in the platform area I, uniformly connecting non-residential electricity consumption of public facilities and the like to a same load side circuit, namely a public facility load circuit, wherein the public facility load circuit is respectively connected to load sides of a public switch I, a public switch II and a public switch III through power cables, and power supply sides of the public switch I, the public switch II and the public switch III are sequentially connected with a matching electric bus A, a matching electric bus B and a matching electric bus C through the power cables;
step 6, in the station area I, equally dividing the secondary users into three parts, namely a primary secondary user, a secondary user and a tertiary secondary user, wherein any one part is connected to the load side of the primary secondary user switch through a power cable, the other two parts are respectively connected to the load sides of the secondary switch II and the secondary switch III, and the power supply sides of the primary secondary user switch I, the secondary user switch II and the secondary user switch III and the power cable are sequentially connected with a first matching power bus, a first matching power bus and a first matching power bus;
step 7, in a station area II adjacent to the station area I, a distribution transformer II is used for providing a three-phase alternating-current power supply for a distribution bus II, and an A-phase distribution bus I is used for connecting power supply sides of a station area two-branch switch 1-1, a station area two-branch switch 1-2 and … … station area two-branch switches 1-N through power cables; connecting a power supply side of a transformer area two-branch switch 2-1, a transformer area two-branch switch 2-2 and an … … transformer area two-branch switch 2-N by using a B-phase distribution bus I through a power cable; connecting a power supply side of a platform area two-branch switch 3-1, a platform area two-branch switch 3-2 and a … … platform area two-branch switch 3-N through a power cable by using a C-shaped matching bus II, wherein a load side of the switches is connected to a load side circuit through the power cable;
step 8, connecting any one end of the phase A power switch with the phase A matching electric bus I through a power cable, and connecting the other end of the phase A power switch with the phase A matching electric bus II through the power cable; connecting any end of the B-phase power switch with a first B-phase matching electric bus through a power cable, and connecting the other end of the B-phase power switch with a second B-phase matching electric bus through a power cable; connecting any end of the C-phase power switch with a first D-phase matching electrical bus through a power cable, and connecting the other end of the C-phase power switch with a second D-phase matching electrical bus through a power cable;
step 9, installing a distribution bus automatic switching device in the station area I, wherein the distribution bus automatic switching device monitors the voltage amplitude and the phase angle of a first phase of a distribution bus, a first phase of the distribution bus, a first phase C of the distribution bus, a second phase A of the distribution bus, a second phase B of the distribution bus and a second phase C of the distribution bus by using a constructed measurement loop II; the automatic switching device of the distribution bus controls the switching-on of the A-phase power switch, the B-phase power switch and the C-phase power switch through the built switching-on control loop, and controls the switching-off of all branch switches in the local area through the built switching-off control loop.
2. The automatic switching device for installing the distribution bus in the first transformer area as claimed in claim 1, wherein: in the step 9, the process is carried out,
when the automatic switching device of the distribution bus detects that the sum of the voltage vectors of the first phase A of the distribution bus, the first phase B of the distribution bus and the first phase C of the distribution bus is greater than a set value, the phase with the lowest voltage and the phase with the highest voltage are judged by measuring the second loop, the lowest phase is the first phase B of the distribution bus, the highest phase is the first phase A of the distribution bus, and the amplitude and the phase angle of the second phase B of the distribution bus in the second distribution area are measured by measuring the second loop. And comparing the amplitude and the phase angle of the voltage of the first phase B of the power distribution bus and the voltage of the second phase B of the power distribution bus, and controlling the switch-on of the switch of the B-phase power supply through the automatic switching device of the power distribution bus if the amplitude and the phase angle are smaller than set values.
When the automatic switching device of the distribution bus detects that the sum of the voltage vectors of the first phase of the distribution bus, the first phase of the distribution bus and the second phase of the distribution bus is still larger than a set value, the phase with the lowest voltage and the phase with the highest voltage are judged by the second measuring loop. If the lowest phase is the first phase B of the distribution bus and the highest phase is the first phase A of the distribution bus, detecting whether the second public switch is at the switching-on position through a data acquisition and control device, if so, switching off the second public switch through an automatic switching device of the distribution bus, and switching on the first public switch through an automatic switching device of the distribution bus within 2S after switching off.
When the automatic switching device of the distribution bus detects that the sum of the voltage vectors of the first phase of the distribution bus, the first phase of the distribution bus and the first phase of the distribution bus is greater than a set value, the lowest phase and the highest phase of the distribution bus are judged by measuring the second phase of the loop, the lowest phase is the first phase of the distribution bus, and the highest phase is the first phase of the distribution bus, and the second phase of the secondary user switch is switched off by the automatic switching device of the distribution bus.
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| US20040196604A1 (en) * | 2003-04-04 | 2004-10-07 | Tmt & D Corporation | Control system for canceling load unbalance of three-phase circuit |
| CN105826939A (en) * | 2014-11-15 | 2016-08-03 | 李春明 | Low-voltage power grid three-phase unbalance automatic adjustment system |
| CN105375500A (en) * | 2015-11-25 | 2016-03-02 | 国家电网公司 | Three-phase unbalance monitoring and management system and method for distribution transformer |
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