CN105529686B - A kind of method and device for overload protection of the distribution transformer of low-voltage distributing line - Google Patents
A kind of method and device for overload protection of the distribution transformer of low-voltage distributing line Download PDFInfo
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- CN105529686B CN105529686B CN201610035165.1A CN201610035165A CN105529686B CN 105529686 B CN105529686 B CN 105529686B CN 201610035165 A CN201610035165 A CN 201610035165A CN 105529686 B CN105529686 B CN 105529686B
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- 238000000034 method Methods 0.000 title claims abstract description 22
- 238000012545 processing Methods 0.000 claims abstract description 62
- 238000004364 calculation method Methods 0.000 claims abstract description 36
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- 230000007774 longterm Effects 0.000 abstract description 3
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/04—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for transformers
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
- H02H7/261—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured involving signal transmission between at least two stations
- H02H7/262—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured involving signal transmission between at least two stations involving transmissions of switching or blocking orders
Abstract
The invention discloses a kind of overload protection method and system of the distribution transformer of low-voltage distributing line, this method includes calculating the electric current of low-voltage distributing line in real time, according to result of calculation, determines that low-voltage distributing line works in combined floodgate section or separating brake section；When working in combined floodgate section, at least one branch road is returned or connected after delay；When working in separating brake section, low-voltage distributing line or at least one branch road are cut off.The system includes current calculation module, combined floodgate processing module and separating brake processing module.Real-time current of the invention according to low-voltage distributing line; carry out classification processing; the branch road that there will be no overload is connected by the way of delay is sent a telegram in reply; to the branch road of overload be present; processing of rationing the power supply is carried out, the distribution transformer long-term work of low-voltage distributing line can be avoided in time to find and take safeguard measure in overload; the service life of distribution transformer can effectively be extended, improve the reliability and the quality of power supply of low-voltage distributing line.
Description
Technical field
The present invention relates to field of relay protection in power, more particularly to a kind of distribution transformer of low-voltage distributing line
Method and device for overload protection.
Background technology
The quickening of Urbanization Construction so that the load electricity of low-voltage network (low pressure refers to less than 1 kilovolt voltage) is continuously increased,
Especially summer peak meeting and seasonal low pressure power load surges during the Spring Festival etc., causes part distribution transformer to be chronically at super negative
Lotus running status.By the investigation to somewhere whole year distribution transformer damaged condition and analysis, low pressure overload is distribution
One of the main reason for transformer damage.
Low pressure is overloaded：GB/T1094.7-2008《The part of power transformer the 7th：Oil-immersed power transformer loads directive/guide》
In point out, transformer normal expected lifetime value be typically using the continuous duty under the environment temperature of design and specified service condition as
Basis.When load is higher than design environment temperature more than nameplate rating and/or environment temperature, transformer will suffer to a certain degree
Danger, and aging accelerate, Distribution Transformer Burning will be caused when serious.
On the one hand the reason for low pressure overload occurs at present is because low-voltage customer power load Seasonal is larger, in addition
In recent years resident load speedup is very fast, so as to cause summer peak meeting and during the Spring Festival distribution transformer overload be difficult to avoid that；The opposing party
Face, the configuration of distribution transformer low-voltage variation are lack of standardization, however it remains low-pressure side does not configure any protection or protection equipment with matching somebody with somebody
The unmatched phenomenon of varying capacity, it is difficult to realize effective protection to distribution transformer.
The content of the invention
Present invention aims at providing a kind of method and device for overload protection of the distribution transformer of low-voltage distributing line, with
The distribution transformer overload for solving low-voltage distributing line is difficult to avoid that and low-voltage variation configuration caused distribution transformer lack of standardization
The flimsy technical problem of device.
To achieve the above object, the invention provides a kind of overload protection side of the distribution transformer of low-voltage distributing line
Method, comprise the following steps：
S1：The electric current of low-voltage distributing line is calculated in real time, according to the result of calculation of electric current, determines that low-voltage distributing line works
In combined floodgate section or separating brake section；
S2：When low-voltage distributing line works in combined floodgate section, return to step S1 or by low-voltage distributing line after delay
At least one branch road connection；
S3：When low-voltage distributing line works in separating brake section, by low-voltage distributing line or low-voltage distributing line at least
One branch road cut-out.
Further improvements in methods as the present invention：
In step S1, according to the result of calculation of electric current, determine that low-voltage distributing line works in combined floodgate section or separating brake area
Between, comprise the following steps：
S1.1：Calculate I/IN, wherein, I be electric current result of calculation, the INFor distribution transformer low-pressure side it is specified
Electric current；
S1.2：If I/IN∈ (0,1.3), it is determined that low-voltage distributing line works in combined floodgate section；
S1.3：If I/IN∈ [1.3 ,+∞), it is determined that low-voltage distributing line works in separating brake section.
Combined floodgate section includes the first combined floodgate section and the second combined floodgate section, step S2 specifically include following steps：
S2.1：When low-voltage distributing line works in combined floodgate section, after delay time t, current I/I is recalculatedN；
S2.2：If I/IN∈ (0,0.8), it is determined that low-voltage distributing line works in the first combined floodgate section, then searches low pressure
Distribution line whether there is branch road separating brake, if branch road separating brake be present, close the switch of at least one branch road, return to step S1；If
In the absence of branch road separating brake, then return to step S1；
S2.3：If I/IN∈ [0.8,1.3), it is determined that low-voltage distributing line works in the second combined floodgate section, delay time t
Afterwards, return to step S1.
In step S2.2, after searching low-voltage distributing line and whether there is branch road separating brake, it is found that low-voltage distributing line is present
During multiple branch road separating brakes, the switch for next branch road that the telegram in reply strategy points to, return to step S1 are closed.
Separating brake section includes the first separating brake section and the second separating brake section, step S3, specifically includes following steps：
S3.1：When low-voltage distributing line works in separating brake section, according to I/INCarry out following judgement：
S3.2：If I/IN∈ [1.3,2.5), it is determined that low-voltage distributing line works in the first separating brake section, then by low pressure
At least one branch road cut-out of distribution line, return to step S1；
S3.3：If I/IN∈ [2.5 ,+∞), it is determined that low-voltage distributing line works in the second separating brake section, then by low pressure
Distribution line is cut off.
In step S3.2, at least one branch road of low-voltage distributing line is cut off, comprised the following steps：
S3.2.1：The order of rationing the power supply of the low-voltage distributing line is come into first most preceding branch according to strategy of rationing the power supply is circulated
Road is cut off, return to step S1.
The technical concept total as one, present invention also offers a kind of overload of the distribution transformer of low-voltage distributing line
Protection device, including：
Current calculation module, for calculating the electric current of low-voltage distributing line in real time, and according to the result of calculation of electric current, selection
Job information is sent to combined floodgate processing module or separating brake processing module；
Combined floodgate processing module, for receiving the job information from current calculation module, and according to job information to electric current
Computing module, which is sent, to be calculated signal or connects at least one branch road of low-voltage distributing line；
Separating brake processing module, for receiving the job information from current calculation module, and according to job information by low pressure
At least one branch road of distribution line or low-voltage distributing line is cut off.
Further improvement as the device of the present invention：
Combined floodgate processing module includes：
Combined floodgate selecting unit, for receiving the job information from current calculation module, and the reality in job information
When current value, select to the first combined floodgate processing unit or the second combined floodgate processing unit sending action signal；
First combined floodgate processing unit, for after the action signal of combined floodgate selecting unit is received, by low-voltage distributing line
At least one branch road connection；
Second combined floodgate processing unit, for after the action signal of combined floodgate selecting unit is received, to current calculation module
Send and calculate signal.
Separating brake processing module includes：
Separating brake selecting unit, for receiving the job information from current calculation module, and the reality in job information
When current value, select to the first separating brake processing unit or the second separating brake processing unit sending action signal；
First separating brake processing unit, for after the action signal of separating brake selecting unit is received, by low-voltage distributing line
At least one branch road cut-out；
Second separating brake processing unit, for after the action signal of separating brake selecting unit is received, by low-voltage distributing line
Cut-out.
The invention has the advantages that：
1st, the overload protection method of the distribution transformer of low-voltage distributing line of the invention, according to the reality of low-voltage distributing line
When electric current, carry out classification processing, there will be no the branch road of overload and connected by the way of delay is sent a telegram in reply, to overload be present
Branch road, processing of rationing the power supply is carried out, the distribution transformer long-term work of low-voltage distributing line can be avoided in overload, in low-voltage distribution
During line work, it can in time find and take safeguard measure, can effectively extend the service life of distribution transformer, improve low pressure
The reliability and the quality of power supply of distribution line.
2nd, in a preferred approach, the overload protection method of the distribution transformer of low-voltage distributing line of the present invention, using circulation
Tactful and delay telegram in reply of rationing the power supply is tactful, can be protected to greatest extent on the basis of distribution transformer safe and stable operation is ensured
Demonstrate,prove low-voltage customer power supply reliability and the fairness of electricity consumption.
3rd, the overload protection arrangement of the distribution transformer of low-voltage distributing line of the invention, it is real-time by current calculation module
Calculating current, further according to the size of current value, line delay telegram in reply is entered in selection by combined floodgate processing module to circuit, or by dividing
Lock processing module is rationed the power supply to branch road, can be rationed the power supply in time when overloading, and in nonoverload, progressively send a telegram in reply.Energy
The damage of distribution transformer is efficiently reduced, extends the service life of distribution transformer, improves power supply quality.
In addition to objects, features and advantages described above, the present invention also has other objects, features and advantages.
Below with reference to accompanying drawings, the present invention is further detailed explanation.
Brief description of the drawings
The accompanying drawing for forming the part of the application is used for providing a further understanding of the present invention, schematic reality of the invention
Apply example and its illustrate to be used to explain the present invention, do not form inappropriate limitation of the present invention.In the accompanying drawings：
Fig. 1 is the flow of the overload protection method of the distribution transformer of the low-voltage distributing line of the preferred embodiment of the present invention
Figure；
Fig. 2 is the stream of the overload protection method of the distribution transformer of the low-voltage distributing line of another preferred embodiment of the present invention
Cheng Tu；
Fig. 3 is that the structure of the overload protection arrangement of the distribution transformer of the low-voltage distributing line of the preferred embodiment of the present invention is former
Manage block diagram；
Fig. 4 is the daily load rate K of distribution transformer<The overload curves figure allowed when 1；
Fig. 5 is 225A breaker actuation curve maps；
Fig. 6 is 400A breaker actuation curve maps.
Embodiment
Embodiments of the invention are described in detail below in conjunction with accompanying drawing, but the present invention can be defined by the claims
Implement with the multitude of different ways of covering.
Referring to Fig. 1, the overload protection method of the distribution transformer of low-voltage distributing line of the invention, comprise the following steps：
S1：The electric current of low-voltage distributing line is calculated in real time, according to the result of calculation of electric current, determines that low-voltage distributing line works
In combined floodgate section or separating brake section；
S2：When low-voltage distributing line works in combined floodgate section, return to step S1 or by low-voltage distributing line after delay
At least one branch road connection；
S3：When low-voltage distributing line works in separating brake section, by low-voltage distributing line or low-voltage distributing line at least
One branch road cut-out.
By above-mentioned steps, it can carry out classification processing according to the real-time current of low-voltage distributing line, there will be no overload
Branch road is connected by the way of delay is sent a telegram in reply, and to the branch road of overload being present, being carried out processing of rationing the power supply, can be avoided low-voltage distribution wire
The distribution transformer long-term work on road when low-voltage distributing line works, can in time be found and take protection to arrange in overload
Apply, can effectively extend the service life of distribution transformer, improve the reliability and the quality of power supply of low-voltage distributing line.
In practical application, in above-mentioned steps, referring to Fig. 2, the mistake of the distribution transformer of low-voltage distributing line of the invention
Guard method is carried, can also be optimized, the embodiment after optimization is as follows：
S1：The electric current of low-voltage distributing line is calculated in real time, according to the result of calculation of electric current, determines that low-voltage distributing line works
It is specific as follows in combined floodgate section or separating brake section：
S1.1：Calculate I/IN, wherein, I be electric current result of calculation, the INFor distribution transformer low-pressure side it is specified
Electric current；
S1.2：If I/IN∈ (0,1.3), it is determined that low-voltage distributing line works in combined floodgate section；
S1.3：If I/IN∈ [1.3 ,+∞), it is determined that low-voltage distributing line works in separating brake section.
S2：When low-voltage distributing line works in combined floodgate section, after delay, return to step S1 or by low-voltage distributing line
At least one branch road connection, it is specific as follows：
S2.1：When low-voltage distributing line works in combined floodgate section, after delay time t, current I/I is recalculatedN。
For the normal operation of effectively protection distribution transforming, close a floodgate all needs to set by rational delay, combined floodgate delay cycle every time
Surely to be determined according to power distribution station low-voltage load with electrical characteristics, by taking urban residents' electricity consumption as an example, the peak times of power consumption of one day occur
In evening 18:00~20:00, to avoid peak times of power consumption, then the delay t that will can close a floodgate is set to 2h, and time t determination can pass through terminal
Low-voltage distributing line history data is gathered, [1.3I is in by distribution low-voltage side electric currentN~2.5IN] section time meter
Calculate delay of closing a floodgate.If overlong time, first removed user can be caused to have a power failure for a long time, influenceing customer power supply can
It is horizontal by property and power supply enterprise's good service, if the time is too short user can be caused frequently to have a power failure, power transmission, to distribution transformer
Safe and stable operation bring hidden danger, can also influence user power utilization experience.Therefore, telegram in reply of being rationed the power supply and be delayed using circulation is tactful,
Low-voltage customer power supply reliability and the fairness of electricity consumption can be effectively ensured on the basis of distribution transforming safe and stable operation is ensured.
S2.2：If I/IN∈ (0,0.8), it is determined that low-voltage distributing line works in the first combined floodgate section, then searches low pressure
Distribution line whether there is branch road separating brake, if branch road separating brake be present, close the switch of at least one branch road, return to step S1；If
In the absence of branch road separating brake, then return to step S1.After searching low-voltage distributing line and whether there is branch road separating brake, low-voltage distribution is found
When circuit has multiple branch road separating brakes, the switch for next branch road that the telegram in reply strategy points to, return to step S1 are closed.
Circulation alleged by embodiment of the present invention strategy of rationing the power supply refers to：When circuit is in the first separating brake section, intelligent distribution transforming
Terminal-pair taiwan area outlet switch takes the mode that circulation is rationed the power supply, and carries out round cut to each branch road load, line is returned back out with distribution low-voltage three
Exemplified by, circulate strategy of rationing the power supply：Branch road 1, branch road 2, branch road 3 represent low pressure three and return back out line respectively, and low-voltage distributing line electric current is in
First separating brake section, then order of rationing the power supply for the first time is branch road 1- branch road 2- branch roads 3, and order of rationing the power supply for the second time is branch road 2- branch roads 3-
Branch road 1, order of rationing the power supply for the third time is branch road 3- branch road 1- branch roads 2.Accordingly, the telegram in reply strategy alleged by the embodiment of the present invention follows
Ring is rationed the power supply, and strategy is similar, i.e., the corresponding telegram in reply rationed the power supply sequentially is respectively：First time telegram in reply order is branch road 1- branch road 2- branch roads 3,
Second of telegram in reply order is branch road 2- branch road 3- branch roads 1, and third time telegram in reply order is branch road 3- branch road 1- branch roads 2.Step S2.2
In, then next branch switch is closed by telegram in reply strategy, referred to：The switch of next branch road pointed by telegram in reply strategy is closed (under i.e.
One switch to be closed a floodgate).
S2.3：If I/IN∈ [0.8,1.3), it is determined that low-voltage distributing line works in the second combined floodgate section, delay time t
Afterwards, return to step S1.
For distribution transformer, [0~0.8] is up section, can close separating brake according to telegram in reply strategy
Branch switch, if [0.8~1.3] then represent distribution transformer be in abnormal operating condition (heavy duty or overload：0.8
~1.0 be heavy duty, and 1.0~1.3 be overload), can be without rationing the power supply in order to ensure user power utilization reliability, but be also not suitable for
Telegram in reply operation.Therefore, combined floodgate section is specifically configured to the first combined floodgate section and the second combined floodgate section, can more accurately monitors and match somebody with somebody
The working condition of piezoelectric transformer, is handled in time.
S3：When low-voltage distributing line works in separating brake section, by low-voltage distributing line or low-voltage distributing line at least
One branch road cut-out, it is specific as follows：
S3.1：When low-voltage distributing line works in separating brake section, according to I/INCarry out following judgement：
S3.2：If I/IN ∈ [1.3,2.5), it is determined that low-voltage distributing line works in the first separating brake section, then by low pressure
At least one branch road cut-out of distribution line, return to step S1；
Wherein, at least one branch road load of cutoff low distribution line, can be rationed the power supply strategy using circulation：
S3.2.1：The order of rationing the power supply of the low-voltage distributing line is come into first most preceding branch according to strategy of rationing the power supply is circulated
Road is cut off, return to step S1.
S3.3：If I/IN∈ [2.5 ,+∞), it is determined that low-voltage distributing line works in the second separating brake section, then by low pressure
Distribution line is cut off.
Illustrate the embodiment of the present invention by stroke in combined floodgate section and separating brake section below according to the actual conditions of low-voltage network
Point threshold value is set to I/IN=1.3, and the division threshold value in the first separating brake section and the second separating brake section is set to I/IN=2.5 original
Cause and advantage：
According to DL/T 499-2001《Rural area low-voltage power technical regulation》：The daily load rate of distribution transformer is less than 1
In the case of, it can allow have appropriate overload in peak hours, the multiple of overload can refer to Fig. 4 song with the duration allowed
Line determines.Wherein, daily load rate K is the ratio of average load in diel and peak load, it is contemplated that rural power load changes
The characteristics of larger, it is apparent from by Fig. 4 curves：Distribution transformer Overflow RateHT (i.e. overload rate) is no more than transformer rated capacity
1.3 again.Therefore I/I is setN=1.3 be the division threshold value in combined floodgate section and separating brake section, the characteristics of more meeting rural power load, symbol
Close actual applicable cases.
The overcurrent protection of distribution transformer low-pressure side is realized using mold cased circuit breaker (air switch) more, it then follows GB/
T14048.2-2008《Low voltage switch equipment and control device part 2：Breaker》Relevant criterion.GB/T 14048.2-2008
Chapters and sections 7.2.1.2.1 regulations " disconnect under breaker overload situations：Overcurrent trip inverse time-delay operation about definite value is in benchmark temperature
Under degree, at 1.05 times of current setting, i.e., conventional non tripping current when, the electrical apparatus release of each phase pole is powered simultaneously, is opened from cold conditions
Begin, should not be threaded off within less than the designated time.In addition, after the designated time terminates, electric current is set to rise to electric current immediately whole
1.30 times of definite value, that is, reach conventional tripping current, and breaker should thread off within less than the designated time as defined in the latter." referring to
Table 1：
The reverse time limiting current of table 1 disconnects disconnection acting characteristic of the electrical apparatus release under fiducial temperature
By at present exemplified by wide variety of rated current 225A and 400A mold cased circuit breaker distribution operation curve,
When breaker load current reaches the 1.3I of rated currentNAnd 2.5INWhen, overcurrent release turn-off time scope such as table 2, Fig. 5 and
Shown in Fig. 6.Using low-voltage variation of the breaker of above acting characteristic as distribution transformer, excessively stream actuation time discreteness compared with
Greatly, 1.3I is reached in distribution transformer load electric currentNWhen, breaker actuation time range is between 200s~7000s, it is difficult to realizes distribution transforming
Accurate overload protection.
The overcurrent release turn-off time of table 2
Analyzed more than passing through, it can be seen that the mold cased circuit breaker action error that distribution transformer low-pressure side uses is big and mistake
Electric current operation curve does not take into full account the overload capacity of distribution transformer, but uses the universal breaker of low pressure as protection
Device, 1.3I occurs in distribution transformingN~2.5INDuring overload, effectively overload protection can not be provided, distribution transformer may be caused to burn
Ruin.
Knowable to analysis more than, the overload protection side of the distribution transformer of the low-voltage distributing line of the embodiment of the present invention
Method, when carrying out classification processing, it can more accurately judge the working condition of low-voltage distributing line, can be with accurate judgement low-voltage distribution
The overload of circuit, there is provided effective overload protection so that the Preservation tactics of distribution transformer more meet actual work shape
State.
On the basis of the principle of uniformity of the above method, referring to Fig. 3, the distribution transformer of low-voltage distributing line of the invention
Overload protection arrangement, including current calculation module, combined floodgate processing module and separating brake processing module, wherein：
Current calculation module, for calculating the electric current of low-voltage distributing line in real time, and according to the result of calculation of electric current, selection
Job information is sent to combined floodgate processing module or separating brake processing module；Combined floodgate processing module, Current calculation is come from for receiving
The job information of module, and according to job information to current calculation module send calculate signal or by low-voltage distributing line extremely
Few branch road connection；Separating brake processing module, for receiving the job information from current calculation module, and according to job information
At least one branch road of low-voltage distributing line or low-voltage distributing line is cut off.The device is calculated in real time by current calculation module
Electric current, further according to the size of current value, selection is entered line delay to circuit by combined floodgate processing module and sent a telegram in reply, or by separating brake at
Reason module is rationed the power supply to branch road, can be rationed the power supply in time when overloading, and in nonoverload, progressively send a telegram in reply.Can be effective
Ground reduces the damage of distribution transformer, extends the service life of distribution transformer, improves power supply quality.
In actual applications, in order that device judgement and action it is more accurate, the system is also extendible, wherein, close a floodgate
Processing module may include combined floodgate selecting unit, the first combined floodgate processing unit and the second combined floodgate processing unit.Wherein, selection of closing a floodgate is single
Member, for receiving the job information from current calculation module, and the real-time current value in job information, select to first
Combined floodgate processing unit or the second combined floodgate processing unit sending action signal；First combined floodgate processing unit, for receiving conjunction
After the action signal of lock selecting unit, at least one branch road of low-voltage distributing line is connected；Second combined floodgate processing unit, is used for
After the action signal of combined floodgate selecting unit is received, sent to current calculation module and calculate signal.The processing of two level combined floodgate is set
Unit, the accurate overload protection of distribution transformer can be further realized, is rationed the power supply by intelligent Distribution transformer using circulation
With telegram in reply strategy, low-voltage customer power supply reliability and use can be effectively ensured on the basis of distribution transforming safe and stable operation is ensured
The fairness of electricity.
Separating brake processing module includes separating brake selecting unit, the first separating brake processing unit and the second separating brake processing unit.Wherein,
Separating brake selecting unit, for receiving the job information from current calculation module, and the real-time current value in job information,
Select to the first separating brake processing unit or the second separating brake processing unit sending action signal；First separating brake processing unit, is used for
After the action signal of separating brake selecting unit is received, at least one branch road of low-voltage distributing line is cut off；At second separating brake
Unit is managed, for after the action signal of separating brake selecting unit is received, low-voltage distributing line to be cut off.
Because the overcurrent protection of distribution transformer low-voltage distributing line is largely using pyromagnetic induction type protection element as distribution
When the short circuit of taiwan area, overload protection device, but distribution transformer operate in 1.3~2.5 times of overloads, it can not realize effective
Overload protection, it using two level separating brake processing unit, can carry on the basis of at utmost ensureing user power utilization reliability, can be achieved
Comprehensive, effective protection of distribution transformer, improve low-voltage customer power supply reliability and power supply quality.
The overload protection method and system of the distribution transformer of the low-voltage distributing line of the embodiment of the present invention are in Hunan Province
The operation test to be maintained secrecy in Utilities Electric Co.'s part power network, the situation before testing are as follows：
This saves whole year in 2012, and rural power grids 10kV distribution transformer damages 1166 altogether, is the main reason for damage：
Overload 32.93%, low-voltage short-circuiting 17.5%, three-phase imbalance 14.24%, thunderbolt 16.21%, apparatus body reason about 14% with
And other reasonses about 6%.Specifically, one is due to that rural area load growth is very fast, is especially largely worked during the Spring Festival
Personnel return to one's native place, and cause throwing-on, cause the main reason that distribution transformer overload is distribution transformer damage；Two are due to
Rural power distribution taiwan area relaying configuration is lack of standardization, however it remains low-pressure side does not configure any protection or protection equipment and distribution transformer
The unmatched phenomenon of device capacity, cause quickly cut off failure during distribution transformer short circuit, cause distribution transformer to burn out；Three
It is due to that taiwan area lightning protection measures are not in place, the problems such as grounding resistance is excessive, arrester damage is not changed in time is present；Fourth, power supply
Institute can not find distribution transforming three-phase imbalance and overload phenomenon in time, cause to distribution transformer general lack of long-range monitoring means
Abnormal operating condition processing not in time, the increase-volume of power distribution station can not also be layouted provide data supporting.
Situation after experiment is as follows：
By the overload protection method and system of the distribution transformer of the low-voltage distributing line of the trial operation embodiment of the present invention,
The distribution transforming caused by low pressure is overloaded effectively is prevented within 2013 to 2015 to damage, distribution transforming can be reduced and damage 385/year, pressed
Per station power distribution transformer, average 10W/ platforms, then can save distribution transformer 38,500,000/year of renewal cost.On the other hand, reduce
User has a power failure phenomenon caused by distribution transforming is burnt, and improves the power supply reliability of user, the amount of being supplied with electric power more, improves power supply enterprise
Social image.
In summary, by real-time calculating current, classification is handled the present invention, and low pressure is matched somebody with somebody according to different situations
Electric line enters line delay telegram in reply and circulation is rationed the power supply, and effectively reduces distribution transformer and is damaged caused by overload, ensures
The power supply reliability and the quality of power supply of low-voltage customer, application effect are good.
The preferred embodiments of the present invention are the foregoing is only, are not intended to limit the invention, for the skill of this area
For art personnel, the present invention can have various modifications and variations.Within the spirit and principles of the invention, that is made any repaiies
Change, equivalent substitution, improvement etc., should be included in the scope of the protection.
Claims (6)
1. a kind of overload protection method of the distribution transformer of low-voltage distributing line, it is characterised in that comprise the following steps：
S1：The electric current of the low-voltage distributing line is calculated in real time；According to the result of calculation of the electric current, the low-voltage distribution is determined
Line work comprises the following steps in combined floodgate section or separating brake section：
S1.1：Calculate I/IN, wherein, the I be the electric current result of calculation, the INFor the low-pressure side of distribution transformer
Rated current；
S1.2：If the I/IN∈ (0,1.3), it is determined that the low-voltage distributing line works in combined floodgate section；
S1.3：If the I/IN∈ [1.3 ,+∞), it is determined that the low-voltage distributing line works in separating brake section；
S2：When the low-voltage distributing line works in combined floodgate section, the combined floodgate section includes the first combined floodgate section and second
Combined floodgate section, after delay, return to step S1 or at least one branch road connection by the low-voltage distributing line, including following step
Suddenly：
S2.1：When the low-voltage distributing line works in combined floodgate section, after delay time t, current I/I is recalculatedN；
S2.2：If the I/IN∈ (0,0.8), it is determined that the low-voltage distributing line works in the first combined floodgate section, then searches institute
State low-voltage distributing line and whether there is branch road separating brake, if branch road separating brake be present, close the switch of at least one branch road, return to step
S1；If branch road separating brake, return to step S1 is not present；
S2.3：If the I/IN∈ [0.8,1.3), it is determined that the low-voltage distributing line works in the second combined floodgate section, during delay
Between after t, return to step S1；
S3：When the low-voltage distributing line works in separating brake section, by the low-voltage distributing line or the low-voltage distribution wire
At least one branch road cut-out on road.
2. overload protection method according to claim 1, it is characterised in that described low searching in the step S2.2
Electric line is press-fitted with the presence or absence of after branch road separating brake, it is found that when the low-voltage distributing line has multiple branch road separating brakes, closes telegram in reply
The switch for next branch road that strategy points to, return to step S1；The telegram in reply strategy refers to：Intelligent distribution transformer terminals are to taiwan area outlet
Switch takes the mode that delay is sent a telegram in reply, and each branch road load is sent a telegram in reply, and the order of telegram in reply is corresponding with order of rationing the power supply.
3. overload protection method according to claim 1 or 2, it is characterised in that the separating brake section includes the first separating brake
Section and the second separating brake section, the step S3, specifically include following steps：
S3.1：When the low-voltage distributing line works in separating brake section, according to the I/INCarry out following judgement：
S3.2：If the I/IN∈ [1.3,2.5), it is determined that the low-voltage distributing line works in the first separating brake section, then by institute
State at least one branch road cut-out of low-voltage distributing line, return to step S1；
S3.3：If the I/IN∈ [2.5 ,+∞), it is determined that the low-voltage distributing line works in the second separating brake section, then by institute
State low-voltage distributing line cut-out.
4. overload protection method according to claim 3, it is characterised in that described to match somebody with somebody low pressure in the step S3.2
At least one branch road cut-out of electric line, comprises the following steps：
S3.2.1：The order of rationing the power supply of the low-voltage distributing line is come first most preceding branch road and cut according to circulation strategy of rationing the power supply
It is disconnected, return to step S1；The strategy of rationing the power supply that circulates refers to：Intelligent distribution transformer terminals take taiwan area outlet switch the side that circulation is rationed the power supply
Formula, each branch road load is cut off in turn.
A kind of 5. overload protection arrangement of the distribution transformer of low-voltage distributing line, it is characterised in that including：
Current calculation module, for calculating the electric current of the low-voltage distributing line in real time, and according to the result of calculation of the electric current,
Select to send job information to combined floodgate processing module or separating brake processing module；
The combined floodgate processing module, believe for receiving the job information from the current calculation module, and according to the work
Cease to send to the current calculation module and calculate signal or connect at least one branch road of the low-voltage distributing line；It is described
Combined floodgate processing module includes：
Combined floodgate selecting unit, for receiving the job information from the current calculation module, and according in the job information
Real-time current value, select to the first combined floodgate processing unit or the second combined floodgate processing unit sending action signal；
First combined floodgate processing unit, for after the action signal of the combined floodgate selecting unit is received, by the low-voltage distribution
At least one branch road connection of circuit；
Second combined floodgate processing unit, for after the action signal of the combined floodgate selecting unit is received, to the Current calculation
Module, which is sent, calculates signal；
The separating brake processing module, believe for receiving the job information from the current calculation module, and according to the work
Breath cuts off at least one branch road of the low-voltage distributing line or the low-voltage distributing line.
6. overload protection arrangement according to claim 5, it is characterised in that the separating brake processing module includes：
Separating brake selecting unit, for receiving the job information from the current calculation module, and according in the job information
Real-time current value, select to the first separating brake processing unit or the second separating brake processing unit sending action signal；
First separating brake processing unit, for after the action signal of the separating brake selecting unit is received, by the low-voltage distribution
At least one branch road cut-out of circuit；
Second separating brake processing unit, for after the action signal of the separating brake selecting unit is received, by the low-voltage distribution
Circuit is cut off.
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| CN201610035165.1A CN105529686B (en) | 2016-01-19 | 2016-01-19 | A kind of method and device for overload protection of the distribution transformer of low-voltage distributing line |
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| CN201610035165.1A CN105529686B (en) | 2016-01-19 | 2016-01-19 | A kind of method and device for overload protection of the distribution transformer of low-voltage distributing line |
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| DE102006003124A1 (en) * | 2006-01-23 | 2007-08-02 | Siemens Ag | Method for implementing an improved thermo-mechanical overload protection and associated overload protection device |
| CN102354987B (en) * | 2011-09-28 | 2013-11-13 | 南京南瑞继保电气有限公司 | Control method of overload load-shedding for transformer or circuit |
| CN202405751U (en) * | 2012-02-01 | 2012-08-29 | 佛山市三水区通利达电力设计有限公司 | Overload protection device of intelligent distribution transformer |
| CN104362589B (en) * | 2014-11-27 | 2017-08-25 | 国家电网公司 | A kind of sectionalised protection device for high overload distribution transformer |
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