CN111130129B

CN111130129B - Multifunctional automatic phase-changing system for medium and low voltage line

Info

Publication number: CN111130129B
Application number: CN202010038052.3A
Authority: CN
Inventors: 张小龙; 明小慧; 杨黄河; 王太平; 赵伟
Original assignee: Anhui Nanrui Zhongtian Electric Power Electronics Co ltd
Current assignee: Anhui Nanrui Zhongtian Electric Power Electronics Co ltd
Priority date: 2018-06-07
Filing date: 2018-06-07
Publication date: 2021-03-02
Anticipated expiration: 2038-06-07
Also published as: CN111181180B; CN111276985A; CN111130130B; CN111130129A; CN108649592B; CN111276985B; CN111181180A; CN111130130A; CN108649592A

Abstract

The invention discloses a multifunctional automatic phase-changing system for a medium-low voltage line. The commutation system comprises a main control module and a plurality of execution modules, wherein each execution module corresponds to a plurality of users connected in parallel. The main control module comprises a main controller and a three-phase voltage sampling unit, each execution module comprises an electronic phase change switch, and the electronic phase change switches select one phase corresponding to the switching command from three power supply phases of the transformer according to the switching command and supply power to a plurality of users corresponding to the execution modules. According to the invention, the aging state of the electronic commutation switch is monitored, and real-time alarm is given, so that the aging monitoring function of the commutation system is realized, the problems of untimely commutation, wrong commutation and the like caused by the aging of the commutation switch are avoided, the commutation success rate and the accuracy of the commutation system are improved, and the commutation efficiency is improved.

Description

Multifunctional automatic phase-changing system for medium and low voltage line

The invention relates to a split application of a multifunctional automatic phase change system for a medium and low voltage line and a phase change method thereof, wherein the application number is CN201810581724.8, the application date is 2018/06/07.

Technical Field

The invention relates to an automatic phase changing system in the technical field of smart power grids, in particular to a multifunctional automatic phase changing system for a medium-low voltage line.

Background

Three-phase load balance is the basis of safe power supply, and three-phase load unbalance can reduce the power supply efficiency of a line and a distribution transformer, and can cause serious consequences such as certain phase lead burnout, switch burnout and even single-phase burnout of the distribution transformer due to overload of heavy-load phases. Therefore, only if the three-phase impedance is balanced, the low-voltage leakage total protection can be ensured to operate well, the personal electric shock casualty accident is prevented, and only if the three-phase load is balanced, the electric energy quality of a user can be ensured. The three-phase load is kept balanced, and the basis of energy consumption saving, loss reduction and price reduction is also realized.

The three-phase load unbalance can be caused by unreasonable layout of medium and low voltage distribution lines of the existing distribution area, different three-phase power user load properties, uncontrollable access of single-phase loads and non-timeliness of the single-phase loads. The three-phase load is seriously asymmetric, the neutral point potential can be deviated, and the line voltage drop and the power loss can be greatly increased. Meanwhile, three-phase load imbalance may cause a line loss rate to increase. In field construction, the condition of phase sequence connection is often wrong, and the field can not be judged. Moreover, in the whole distribution line, the line loss is not monitored, and electricity stealing phenomena often occur, which cause great economic loss to power supply companies.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides a multifunctional automatic phase change system for a medium and low voltage line, which avoids the problems of untimely phase change, phase change errors and the like caused by aging of a phase change switch.

(II) technical scheme

In order to achieve the purposes of energy conservation and high real-time performance, the invention provides the following technical scheme: a multifunctional automatic phase change system for a medium-low voltage line is applied to a power distribution station and comprises a main control module arranged at a transformer end of the station and a plurality of execution modules arranged at a user end; each execution module comprises an electronic commutation switch, a voltage sampling unit, an aging alarm device, an execution controller, a current sampling unit, a single-phase voltage sampling unit, a single-phase current sampling unit and a phase sequence error alarm device;

the main control module comprises a main controller and a three-phase voltage sampling unit; the three-phase voltage sampling unit detects the three-phase voltage U output by the transformer_A1、U_B1、U_C1The single-phase voltage sampling unit detects the voltage U of the electronic commutation switch when the electronic commutation switch sequentially commutates to the A phase, the B phase and the C phase_A2、U_B2、U_C2(ii) a The single-phase current sampling unit detects the current I which passes through the electronic phase change switch when the phase change switch sequentially changes phases to A phase, B phase and C phase_A1、I_B1、I_C1；

The main controller judges U_A1、U_B1、U_C1Whether the mutual voltage difference is greater than a preset voltage difference one or not is judged, if so, the following steps are carried out: further judge U_A1And U_A2Voltage difference of U_B1And U_B2Voltage difference of U_C1And U_C2Whether the voltage difference is smaller than a second preset voltage, a third preset voltage and a fourth preset voltage or not is judged, and if not, the phase sequence error alarm device is driven to alarm; otherwise: judging whether the time is within a preset time II_AAnd I_A1，I_BAnd I_B1，I_CAnd I_C1Whether the current difference is smaller than a preset current difference two, a preset current difference three and a preset current difference four or not is judged, and if not, the phase sequence error alarm device is driven to alarm;

the voltage sampling unit detects the voltages at two ends of the electronic commutation switch when the electronic commutation switch is closed, the execution controller judges whether the voltage difference at two ends of the electronic commutation switch exceeds a preset voltage difference, and if so, the execution controller drives the aging alarm device to alarm;

after the electronic commutation switch is closed, the voltage of the electronic commutation switch fluctuates within a preset time II and reaches a stable state after the preset time II, and the voltage sampling unit detects the peak voltage within the preset time II after the electronic commutation switch is closed and the stable voltage when the voltage reaches the stable state after the preset time II; and the execution controller judges whether the voltage difference between the peak voltage and the stable voltage exceeds a preset voltage difference five, and if so, the execution controller drives the aging alarm device to alarm.

As a further improvement of the above scheme, the main control module further comprises a three-phase current sampling unit; the three-phase current sampling unit is used for detecting the three-phase current I output by the transformer in real time_A、I_B、I_C(ii) a The main controller firstly bases on the three-phase current I_A、I_B、I_CCalculating three-phase unbalance degree sigma, sigma ═ I ((I)_max-I_min)/I_max) X 100%, wherein, I_maxAs a three-phase current I_A、I_B、I_CMaximum value of (1), I_minAs a three-phase current I_A、I_B、I_CIf the three-phase unbalance degree sigma reaches a preset three-phase unbalance degree, continuously judging whether the duration time of the three-phase unbalance degree sigma reaching the preset three-phase unbalance degree reaches a preset time I, if so, calculating a switching scheme and outputting a switching command;

and the electronic phase change switch selects one phase corresponding to the switching command from the three power supply phases of the transformer according to the switching command, and supplies power to a plurality of users corresponding to the execution module.

Further, the switching scheme is to compare the switching combinations of the phase change switches according to the current imbalance condition: screening was performed according to A, B two constraints, a: the optimal three-phase balance is achieved; b: the number of switching actions required for the switching scheme is minimal.

Furthermore, in order to enhance the predictive regulation capability of commutation switching on three-phase balance, the regulation is divided into predictive switching and temporary switching; predictive handover: actively switching before the three-phase imbalance reaches a switching set critical value; the method comprises the steps of mastering regular imbalance occurrence information by counting power utilization curve conditions in a long time, predictively calculating unbalanced rule occurrence conditions, switching in advance and limiting unbalanced occurrence; and (3) temporary switching: and aiming at irregular temporary unbalance, when the set value is reached, carrying out phase change adjustment temporarily.

As a further improvement of the above scheme, the main control module further includes a first three-phase voltage sampling unit and a line alarm device, and the first three-phase voltage sampling unit detects a three-phase voltage U output by the phase change system at the side of the transformer during no-load_A1、U_B1、U_C1And three-phase voltage U output by the side of the on-load transformer_A2、U_B2、U_C2(ii) a Each execution module further comprises a second three-phase voltage sampling unit, and the second three-phase voltage sampling unit detects a three-phase voltage U output by the electronic phase change switch side when the phase change system is in no-load state_A3、U_B3、U_C3And three-phase voltage U output by the side of the electronic phase change switch when the load is carried_A4、U_B4、U_C4；

The main controller judges U_A1And U_A3Voltage difference of U_A2And U_A4And if the voltage difference exceeds a preset voltage difference one, driving the line alarm device to alarm for the phase A line.

Further, the main controller also judges U_B1And U_B3Voltage difference of U_B2And U_B4And if the voltage difference exceeds a preset voltage difference two, driving the line alarm device to alarm for the B-phase line.

Still further, the main controller also judges U_C1And U_C3Voltage difference of U_C2And U_C4And if the voltage difference exceeds a preset voltage difference three, driving the line alarm device to alarm for the C-phase line.

As a further improvement of the above scheme, each execution module further comprises an electric quantity metering device, and the main control module further comprises an electricity stealing alarm device; the electric quantity metering device meters the total electricity consumption of a plurality of users corresponding to the execution module within a preset time, the main controller judges whether the electricity quantity difference between the total electricity consumption and the meter reading electric quantity of the user side exceeds a preset electricity quantity difference, and if yes, the electricity stealing alarm device is driven to alarm.

As a further improvement of the scheme, each execution module further comprises a super capacitor, a power failure alarm device, a voltage sampling unit and an execution controller; the output end of the phase change switch is connected with a branch box, and the output end of the branch box is connected with a plurality of users corresponding to the execution module; the voltage sampling unit detects the voltage of the commutation switch and the voltage at the output end of the branch box, and the execution controller judges whether the voltage detected by the voltage sampling unit is smaller than a preset voltage or not, and drives the power failure alarm device electrically connected with the super capacitor to alarm if the voltage detected by the voltage sampling unit is smaller than the preset voltage.

As a further improvement of the above scheme, the execution module further comprises a temperature sensor and an overheating alarm device; the temperature sensor detects the temperature of the phase change switch, the main controller judges whether the temperature detected by the temperature sensor is greater than a preset temperature or not, and if yes, the overheating alarm device is driven to give an alarm.

(III) advantageous effects

Compared with the prior art, the invention provides a multifunctional automatic phase-changing system for a medium-low voltage line, which has the following beneficial effects:

1. the multifunctional automatic phase-changing system for the medium and low voltage lines, provided by the invention, divides the lines of a power distribution area by arranging the main control module and the execution modules, the execution module is arranged at the tail end of each line, and the main control module arranged at the end of the power distribution transformer controls the execution modules to switch the three phases of each line, so that the three-phase power loads of all the lines tend to be balanced after switching, thereby improving the unbalance of the three phases, reducing the line loss of the power distribution area, ensuring the good operation of low-voltage leakage general protection, preventing the personal electric shock casualty accidents, ensuring the power quality of users, and achieving the purposes of saving energy and reducing the electricity price.

2. According to the multifunctional automatic commutation system for the medium and low voltage lines, the aging state of the electronic commutation switch is monitored, and real-time alarming is performed, so that the aging monitoring function of the commutation system is realized, the problems of untimely commutation, phase commutation error and the like caused by the aging of the commutation switch are avoided, the commutation success rate and the accuracy of the commutation system are improved, and the commutation efficiency is improved.

3. According to the multifunctional automatic phase change system for the medium and low voltage lines, the voltage drop condition of each line in the power distribution station area is monitored, alarm information is sent when the voltage drop is too large, so that the line is reminded of being overhauled or replaced, the line monitoring function of the phase change system is realized, the line loss of the power distribution line is reduced, the utilization rate of electric energy is improved, and the electric power transmission cost is reduced.

4. The multifunctional automatic commutation system for the medium and low voltage lines realizes the electricity larceny prevention function of the commutation system and reduces the economic loss of a power supply company by monitoring the electricity consumption of users of all lines, comparing the electricity consumption with the meter reading electricity quantity and sending electricity larceny alarm information when the electricity quantity difference is overlarge.

5. According to the multifunctional automatic phase change system for the medium and low voltage lines, the voltage state is monitored in real time by monitoring the voltage of the phase change switch and the voltage of the branch box, so that the power failure alarm function of the phase change system is realized, maintenance personnel can maintain the lines conveniently in time, and the power utilization quality of users is improved.

6. The multifunctional automatic phase change system for the medium and low voltage lines judges whether the phase sequence is wrong or not by detecting the three-phase voltage and current change from the transformer to the phase change switch, realizes the function of monitoring the phase sequence of the phase change system, and improves the sensing capability of the tail end of the line of the transformer area.

7. According to the multifunctional automatic phase change system for the medium and low voltage lines, the temperature of the phase change switch is monitored by arranging the temperature sensor, so that the temperature monitoring function of the phase change system is realized, the situation that the phase change switch is burnt due to overhigh temperature is avoided, the use cost of the phase change switch is reduced, meanwhile, the fire caused by the burning of the phase change switch is avoided, and the safety of the phase change system is improved.

Drawings

FIG. 1 is a block system connection diagram of a multifunctional automatic phase change system for medium and low voltage lines in embodiment 1 of the present invention

FIG. 2 is a system framework diagram of the master control module of FIG. 1;

FIG. 3 is a system framework diagram of the execution module of FIG. 1;

fig. 4 is a system framework diagram of the multifunctional automatic phase change system for the medium and low voltage lines according to embodiment 1 of the present invention;

fig. 5 is a system framework diagram of an execution module of the multifunctional automatic commutation system for medium and low voltage lines according to embodiment 2 of the present invention;

fig. 6 is a system framework diagram of the multifunctional automatic phase change system for the medium and low voltage lines according to embodiment 2 of the present invention;

fig. 7 is a system framework diagram of an execution module of the multifunctional automatic commutation system for medium and low voltage lines according to embodiment 3 of the present invention;

fig. 8 is a system framework diagram of the multifunctional automatic commutation system for medium and low voltage lines according to embodiment 3 of the present invention;

fig. 9 is a system framework diagram of a main control module of the multifunctional automatic commutation system for medium and low voltage lines according to embodiment 4 of the present invention;

fig. 10 is a system framework diagram of an execution module of the multifunctional automatic commutation system for medium and low voltage lines according to embodiment 4 of the present invention;

fig. 11 is a system framework diagram of the multifunctional automatic commutation system for medium and low voltage lines according to embodiment 4 of the present invention;

fig. 12 is a system framework diagram of a main control module of the multifunctional automatic commutation system for medium and low voltage lines according to embodiment 5 of the present invention;

fig. 13 is a system framework diagram of an execution module of the multifunctional automatic commutation system for medium and low voltage lines according to embodiment 5 of the present invention;

fig. 14 is a system framework diagram of the multifunctional automatic phase commutation system for the medium and low voltage lines according to embodiment 5 of the present invention;

fig. 15 is a system framework diagram of an execution module of the multifunctional automatic commutation system for medium and low voltage lines according to embodiment 6 of the present invention;

fig. 16 is a system framework diagram of the multifunctional automatic phase commutation system for medium and low voltage lines according to embodiment 6 of the present invention;

fig. 17 is a system framework diagram of a main control module of the multifunctional automatic commutation system for medium and low voltage lines according to embodiment 7 of the present invention;

fig. 18 is a system framework diagram of an execution module of the multifunctional automatic commutation system for medium and low voltage lines according to embodiment 7 of the present invention;

fig. 19 is a system framework diagram of the multifunctional automatic commutation system for medium and low voltage lines according to embodiment 7 of the present invention;

fig. 20 is a system framework diagram of an execution module of the multifunctional automatic commutation system for medium and low voltage lines according to embodiment 8 of the present invention;

fig. 21 is a system block diagram of a multifunctional automatic phase change system for medium and low voltage lines according to embodiment 8 of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

Referring to fig. 1, the multifunctional automatic phase-change system for medium and low voltage lines of the present embodiment is applied to a distribution substation, and the phase-change system includes a main control module disposed at a transformer end of the substation and a plurality of execution modules disposed at a user end, where each execution module corresponds to a plurality of users connected in parallel.

Referring to fig. 2, the main control module includes a main controller, a three-phase current sampling unit, a first key display unit, and a signal transmitting unit. Three-phase current sampling unit for detecting three-phase current I output by transformer in real time_A、I_B、I_C. The signal transmitting unit is used for remotely transmitting the current information detected by the three-phase current sampling unit to a main power grid station, and simultaneously transmitting other information to the main station. The signal transmitting unit can adopt a GSM module and communicates with the master station. Thus, can be formed at the main stationAnd the three-phase load curve of each station area is convenient for mastering the running state of the power grid in real time. The key display unit I is used for displaying current information detected by the three-phase current sampling unit, and the operating data of the main control module can be manually inquired by setting the key display unit I, so that the operating state of a distribution room can be known, and personnel can conveniently monitor and maintain in real time. The main controller firstly uses three-phase current I_A、I_B、I_CCalculating three-phase unbalance degree sigma, sigma ═ I ((I)_max-I_min)/I_max) X 100%, wherein, I_maxAs a three-phase current I_A、I_B、I_CMaximum value of (1), I_minAs a three-phase current I_A、I_B、I_CAnd if so, continuously judging whether the duration time for the three-phase unbalance degree sigma to reach the preset three-phase unbalance degree reaches a preset time I, if so, calculating a switching scheme, and outputting a switching command. In this embodiment, the main controller and the execution module may communicate with each other in a broadband power carrier manner, which may save communication cost and improve communication quality.

The switching scheme is that phase change switch switching combination comparison is carried out according to the current unbalanced condition: the screening was performed according to A, B two constraints. A: the optimal three-phase balance is achieved; b: the number of switching actions required for the switching scheme is minimal.

Meanwhile, in order to enhance the predictive regulation capability of commutation switching on three-phase balance, regulation is divided into predictive switching and temporary switching.

Predictive handover: and actively switching before the three-phase imbalance reaches the switching set critical value. The method comprises the steps of counting power utilization curve conditions in a long time, mastering regular imbalance occurrence information, predictively calculating the irregular imbalance occurrence conditions, switching in advance and limiting imbalance occurrence.

And (3) temporary switching: and aiming at irregular temporary unbalance, when the set value is reached, carrying out phase change adjustment temporarily.

Referring to fig. 3 and 4, each of the execution modules includes an electronic commutation switch, a second key display unit, and an execution controller, and the electronic commutation switch selects one phase corresponding to the switching command among three phases of the power supply of the transformer according to the switching command to supply power to a plurality of users corresponding to the execution modules. The execution controller drives the key display unit II to display the overlapped phase sequence of the electronic phase change switch after the phase change, so that maintenance personnel can conveniently check and maintain the electronic phase change switch on site.

The embodiment also discloses a phase change method of the multifunctional automatic phase change system for the medium and low voltage lines, which comprises the following steps:

(1) the main controller calculates the three-phase unbalance of the transformer according to the three-phase current detected by the three-phase current sampling unit in real time;

(2) the main controller judges whether the three-phase unbalance degree reaches a preset three-phase unbalance degree, if so, the main controller continuously judges whether the duration time of the three-phase unbalance degree reaching the preset three-phase unbalance degree reaches a preset time I, if so, the main controller calculates a switching scheme and outputs a switching command;

(3) and the electronic phase change switch selects one phase corresponding to the switching command from the three power supply phases of the transformer according to the switching command, and supplies power to a plurality of users corresponding to the execution module.

In summary, in the multifunctional automatic phase change system for medium and low voltage lines and the phase change method thereof according to the embodiment, the lines of the distribution substation area are divided by arranging the main control module and the execution modules, one execution module is installed at the tail end of each line, and the main control module arranged at the distribution transformer end controls the execution modules to switch the three phases of each line, so that the three-phase electric loads of all the switched lines tend to be balanced, and therefore, the unbalance of the three phases is improved, the line loss of the distribution substation area is reduced, the low-voltage leakage general protection is ensured to operate well, the personal electric shock casualty accidents are prevented, the electric energy quality of users is ensured, and the purposes of saving energy and reducing electricity price are achieved.

Example 2

Referring to fig. 5 and 6, the multifunctional automatic phase-changing system for medium and low voltage lines of the present embodiment is added with a voltage sampling unit and an aging alarm device disposed in the execution module based on embodiment 1. The voltage sampling unit detects the voltages at two ends of the electronic commutation switch when the electronic commutation switch is closed, the execution controller judges whether the voltage difference at two ends of the electronic commutation switch exceeds a preset voltage difference, and if so, the execution controller drives the aging alarm device to alarm.

In other embodiments, after the electronic commutation switch is closed, the voltage fluctuates within a preset time period two and is stable after the preset time period two. The voltage sampling unit can also detect the peak voltage within the preset time II after the electronic commutation switch is closed and the stable voltage when the voltage is stable after the preset time II; and the execution controller judges whether the voltage difference between the peak voltage and the stable voltage exceeds a preset voltage difference, and if so, the execution controller drives the aging alarm device to alarm.

The multifunctional automatic commutation system for the medium and low voltage lines realizes the aging monitoring function of the commutation system by monitoring the aging state of the electronic commutation switch and giving an alarm in real time, avoids the problems of untimely commutation, phase commutation error and the like caused by the aging of the commutation switch, improves the commutation success rate and accuracy of the commutation system, and improves the commutation efficiency.

Example 3

Referring to fig. 7 and 8, in the multifunctional automatic phase change system for medium and low voltage lines of the present embodiment, a current sampling unit and an aging alarm device disposed in an execution module are added on the basis of embodiment 1. After the electronic commutation switch is closed, the current fluctuates within a preset time II and becomes stable after the preset time II; the current sampling unit detects the peak current within a preset time II after the electronic commutation switch is closed and the steady current when the electronic commutation switch reaches steady after the preset time II; and the execution controller judges whether the voltage difference between the peak current and the steady current exceeds a preset current difference, and if so, the execution controller drives the aging alarm device to alarm.

The multifunctional automatic commutation system for the medium and low voltage lines is suitable for aging alarm monitoring under the condition that the voltage change of the commutation switch is not obvious, and can also achieve the same beneficial effects as embodiment 2.

Example 3

Referring to fig. 9-11, in the multifunctional automatic phase change system for a medium and low voltage line of the present embodiment, a first three-phase voltage sampling unit and a line alarm device, which are arranged in a main control module, and a second three-phase voltage sampling unit, which is arranged in an execution module, are added on the basis of embodiment 1.

The first three-phase voltage sampling unit detects three-phase voltage U output by the transformer side when the phase change system is in no load_A1、U_B1、U_C1And three-phase voltage U output by the side of the on-load transformer_A2、U_B2、U_C2. The second three-phase voltage sampling unit detects the three-phase voltage U output by the electronic phase change switch side when the phase change system is in no-load_A3、U_B3、U_C3And three-phase voltage U output by the side of the electronic phase change switch when the load is carried_A4、U_B4、U_C4. The main controller judges U_A1And U_A3Voltage difference of U_A2And U_A4If the voltage difference exceeds a preset voltage difference one, if so, the driving circuit alarm device alarms aiming at the phase A line and also judges whether the phase U line is in a U state_B1And U_B3Voltage difference of U_B2And U_B4If the voltage difference exceeds a preset voltage difference two, the driving circuit alarm device alarms aiming at the phase B line and also judges whether the phase U line is in a state of being in a state of_C1And U_C3Voltage difference of U_C2And U_C4And if the voltage difference exceeds a preset voltage difference three, the driving circuit alarm device alarms aiming at the C-phase circuit.

The multi-functional automatic commutation system of well low voltage circuit of this embodiment sends alarm information when the pressure drop is too big through the voltage drop condition of each circuit in the monitoring distribution station district to remind to overhaul or change the circuit, realize commutation system's line monitoring function, reduce distribution lines's line loss, improve the utilization ratio of electric energy, reduce electric power transmission cost.

Example 5

Referring to fig. 12-14, the multifunctional automatic phase-changing system for medium and low voltage lines of the present embodiment is added with an electricity stealing alarm device disposed in the main control module and an electricity metering device disposed in the execution module based on embodiment 1. The electric quantity metering device meters the total electric quantity of a plurality of users corresponding to the execution module within a preset time II, the main controller judges whether the electric quantity difference between the total electric quantity and the meter reading electric quantity of the user side exceeds a preset electric quantity difference, and if so, the electric quantity metering device drives the electric larceny alarm device to alarm.

The multifunctional automatic commutation system for the medium and low voltage lines of the embodiment realizes the electricity larceny prevention function of the commutation system and reduces the economic loss of a power supply company by monitoring the electricity consumption of users of all lines, comparing the electricity consumption with the meter reading electricity quantity and sending electricity larceny alarm information when the electricity quantity difference is overlarge.

Example 6

Referring to fig. 15 and 16, in the multifunctional automatic phase change system for medium and low voltage lines according to the present embodiment, a super capacitor, a power failure alarm device, and a voltage sampling unit are added to an execution module based on embodiment 1. The output end of the phase change switch is connected with a branch box, and the output end of the branch box is connected with a plurality of users corresponding to the execution module; the voltage sampling unit detects the voltage of the commutation switch and the voltage at the output end of the branch box, the execution controller judges whether the voltage detected by the voltage sampling unit is smaller than a preset voltage, and if so, the execution controller drives the power failure alarm device electrically connected with the super capacitor to alarm.

The multifunctional automatic phase change system for the medium and low voltage lines of the embodiment monitors the voltage state in real time by monitoring the voltage of the phase change switch and the branch box, thereby realizing the power failure alarm function of the phase change system, facilitating maintenance personnel to maintain the lines in time and improving the power utilization quality of users.

Example 7

Referring to fig. 17 to 19, in the multifunctional automatic phase change system for medium and low voltage lines of the present embodiment, a three-phase voltage sampling unit disposed in a main control module, a single-phase voltage sampling unit disposed in an execution module, a single-phase current sampling unit, and a phase sequence error alarm device are added on the basis of embodiment 1.

Three-phase voltage U output by detecting transformer by three-phase voltage sampling unit_A1、U_B1、U_C1When the single-phase voltage sampling unit detects that the phase change switch changes the phase to the A phase, the B phase and the C phase in sequenceVoltage U of commutation switch_A2、U_B2、U_C2. The single-phase current sampling unit detects the current I passing through the phase change switch when the phase change switch sequentially changes the phase to the A phase, the B phase and the C phase_A1、I_B1、I_C1。

The main controller judges U_A1、U_B1、U_C1Whether the mutual voltage difference is greater than a preset voltage difference one or not is judged, if so, the following steps are carried out: further judge U_A1And U_A2Voltage difference of U_B1And U_B2Voltage difference of U_C1And U_C2Whether the voltage difference is smaller than a second preset voltage, a third preset voltage and a fourth preset voltage or not is judged, and if not, a phase sequence error alarm device is driven to alarm; otherwise: judging whether the time is within a preset time II_AAnd I_A1，I_BAnd I_B1，I_CAnd I_C1Whether the current difference is smaller than a preset current difference two, a preset current difference three and a preset current difference four or not is judged, and if not, the phase sequence error alarm device is driven to alarm.

The multifunctional automatic phase change system for the medium and low voltage lines judges whether the phase sequence is wrong or not by detecting the three-phase voltage and current change from the transformer to the phase change switch, realizes the function of monitoring the phase sequence of the phase change system, and improves the sensing capability of the tail end of the line of the transformer area.

Example 8

Referring to fig. 20 and 21, in the multifunctional automatic phase change system for medium and low voltage lines of the present embodiment, a temperature sensor and an overheat alarm device disposed in an execution module are added on the basis of embodiment 1. The temperature sensor detects the temperature of the phase change switch, the main controller judges whether the temperature detected by the temperature sensor is greater than a preset temperature or not, and if yes, the overheating alarm device is driven to alarm.

The multifunctional automatic phase change system and the phase change method for the medium and low voltage lines in the embodiment monitor the temperature of the phase change switch by arranging the temperature sensor, realize the temperature monitoring function of the phase change system, avoid the situation that the phase change switch is burnt due to overhigh temperature, reduce the use cost of the phase change switch, simultaneously avoid fire disasters caused by the burning of the phase change switch, and improve the safety of the phase change system.

Example 9

The multifunctional automatic commutation system of the middle-low voltage circuit of the embodiment combines the structures of all the embodiments, realizes the multi-functionalization and full automation of the commutation system, and the main controller can also transmit all alarm information to the main station through the signal transmitting unit, so that the main station personnel know the running state of the transformer area at the first time, and make corresponding processing, the fault feedback capacity of the transformer area is improved, the power supply quality is improved, less power loss is realized, a power supply company can conveniently perform targeted maintenance, and the three-phase load of the transformer area is balanced to the maximum extent.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. The utility model provides a multi-functional automatic commutation system of well low voltage line, commutation system uses in a distribution station district its characterized in that: the phase change system comprises a main control module arranged at a transformer end of the transformer area and a plurality of execution modules arranged at a user end; each execution module corresponds to a plurality of users connected in parallel, and comprises an electronic commutation switch, a voltage sampling unit, an aging alarm device, an execution controller, a single-phase voltage sampling unit, a single-phase current sampling unit and a phase sequence error alarm device;

The main controller judges U_A1、U_B1、U_C1Whether the mutual voltage difference is greater than a preset voltage difference I or not, when U is greater than a preset voltage difference I_A1、U_B1、U_C1When the mutual voltage difference is larger than the preset voltage difference, further judging U_A1And U_A2Whether the voltage difference is less than a preset voltage two, U_B1And U_B2Whether the voltage difference is less than a preset voltage three, U_C1And U_C2Whether the voltage difference is less than a preset voltage of four, when U_A1And U_A2Is not less than the second preset voltage, and U_B1And U_B2Is not less than the preset voltage three, and U_C1And U_C2When the voltage difference is not less than the preset voltage, driving the phase sequence error alarm device to alarm; when U is turned_A1、U_B1、U_C1When the mutual voltage difference is not more than the preset voltage difference, I is judged within a preset time II_AAnd I_A1Whether the current difference is less than a preset current difference of two, I_BAnd I_B1Whether the current difference is less than a preset current difference of three, I_CAnd I_C1Whether the current difference is less than a preset current difference of four, when I_AAnd I_A1Is not less than the preset current difference of two, and I_BAnd I_B1Is not less than the preset current difference three, and I_CAnd I_C1When the current difference is not less than the preset current difference, the phase sequence error alarm device is driven to alarm;

2. The multifunctional automatic phase-changing system for the medium and low voltage lines as claimed in claim 1, wherein: the main control module also comprises a three-phase current sampling unit; the three-phase current sampling unit is used for detecting the three-phase current I output by the transformer in real time_A、I_B、I_C(ii) a The main controller firstly bases on the three-phase current I_A、I_B、I_CCalculating three-phase unbalance degree sigma, sigma ═ I ((I)_max-I_min)/I_max) X 100%, wherein, I_maxAs a three-phase current I_A、I_B、I_CMaximum value of (1), I_minAs a three-phase current I_A、I_B、I_CIf the three-phase unbalance degree sigma reaches a preset three-phase unbalance degree, continuously judging whether the duration time of the three-phase unbalance degree sigma reaching the preset three-phase unbalance degree reaches a preset time I, if so, calculating a switching scheme and outputting a switching command;

3. The multifunctional automatic phase-changing system for the medium and low voltage lines as claimed in claim 2, wherein: the switching scheme is that phase change switch switching combination comparison is carried out according to the current unbalanced condition: screening was performed according to A, B two constraints, a: the optimal three-phase balance is achieved; b: the number of switching actions required for the switching scheme is minimal.

4. The multifunctional automatic phase-changing system for the medium and low voltage lines as claimed in claim 3, wherein: in order to enhance the predictive regulation capability of commutation switching on three-phase balance, the regulation is divided into predictive switching and temporary switching; predictive handover: actively switching before the three-phase imbalance reaches a switching set critical value; the method comprises the steps of mastering regular imbalance occurrence information by counting power utilization curve conditions in a long time, predictively calculating unbalanced rule occurrence conditions, switching in advance and limiting unbalanced occurrence; and (3) temporary switching: and aiming at irregular temporary unbalance, when the set value is reached, carrying out phase change adjustment temporarily.

5. The multifunctional automatic phase-changing system for the medium and low voltage lines as claimed in claim 1, wherein: the main control module further comprises a three-phase voltage sampling unit I and a line alarm device, wherein the three-phase voltage sampling unit I detects a three-phase voltage U output by the phase change system at the side of the transformer during no-load_A1、U_B1、U_C1And three-phase voltage U output by the side of the on-load transformer_A2、U_B2、U_C2(ii) a Each execution module further comprises a second three-phase voltage sampling unit, and the second three-phase voltage sampling unit detects a three-phase voltage U output by the electronic phase change switch side when the phase change system is in no-load state_A3、U_B3、U_C3And three-phase voltage U output by the side of the electronic phase change switch when the load is carried_A4、U_B4、U_C4；

6. The multifunctional automatic phase-changing system for the medium and low voltage lines as claimed in claim 5, wherein: the main controller also judges U_B1And U_B3Voltage difference of U_B2And U_B4And if the voltage difference exceeds a preset voltage difference two, driving the line alarm device to alarm for the B-phase line.

7. The multifunctional automatic phase-changing system for the medium and low voltage lines as claimed in claim 6, wherein: the main controller also judges U_C1And U_C3Voltage difference of U_C2And U_C4And if the voltage difference exceeds a preset voltage difference three, driving the line alarm device to alarm for the C-phase line.

8. The multifunctional automatic phase-changing system for the medium and low voltage lines as claimed in claim 1, wherein: each execution module further comprises an electric quantity metering device, and the main control module further comprises an electricity stealing alarm device; the electric quantity metering device meters the total electricity consumption of a plurality of users corresponding to the execution module within a preset time, the main controller judges whether the electricity quantity difference between the total electricity consumption and the meter reading electric quantity of the user side exceeds a preset electricity quantity difference, and if yes, the electricity stealing alarm device is driven to alarm.

9. The multifunctional automatic phase-changing system for the medium and low voltage lines as claimed in claim 1, wherein: each execution module also comprises a super capacitor, a power failure alarm device, a voltage sampling unit and an execution controller; the output end of the phase change switch is connected with a branch box, and the output end of the branch box is connected with a plurality of users corresponding to the execution module; the voltage sampling unit detects the voltage of the commutation switch and the voltage at the output end of the branch box, and the execution controller judges whether the voltage detected by the voltage sampling unit is smaller than a preset voltage or not, and drives the power failure alarm device electrically connected with the super capacitor to alarm if the voltage detected by the voltage sampling unit is smaller than the preset voltage.

10. The multifunctional automatic phase-changing system for the medium and low voltage lines as claimed in claim 1, wherein: the execution module also comprises a temperature sensor and an overheating alarm device; the temperature sensor detects the temperature of the phase change switch, the main controller judges whether the temperature detected by the temperature sensor is greater than a preset temperature or not, and if yes, the overheating alarm device is driven to give an alarm.