CN109980602A - A kind of transformer digital self-adapting protective device and method based on pressure characteristic - Google Patents
A kind of transformer digital self-adapting protective device and method based on pressure characteristic Download PDFInfo
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- CN109980602A CN109980602A CN201910376457.5A CN201910376457A CN109980602A CN 109980602 A CN109980602 A CN 109980602A CN 201910376457 A CN201910376457 A CN 201910376457A CN 109980602 A CN109980602 A CN 109980602A
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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
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Abstract
A kind of transformer digital self-adapting protective device and method based on pressure characteristic, comprising: transient state oil pressure feature measurement module, switching input module, signal condition and acquisition module, digital core module；Wherein, transient state oil pressure feature measurement module is connected with signal condition with acquisition module, and signal condition is connected with digital core module with acquisition module and switching input module.The present invention obtains the multiple measuring point transient state oil pressure digital informations of fuel tank internal in real time; operation obtains the operating pressure value of characterization oil pressure amplitude; Protection criteria and threshold value setting method are constructed using significant difference existing for this feature amount under transformer difference service condition; it realizes reliable, quick, the sensitive examination and excision to oil tank of transformer internal fault, and is not influenced by excitation surge current.Meanwhile the present invention devises malfunction is adaptive, threshold value is adaptive protection scheme is to improve the movement speed of protection.
Description
Technical field
The invention belongs to field of power systems, are related to a kind of transformer digital self-adapting protection dress based on pressure characteristic
It sets and method, is used for reliable, quick, sensitive examination oil-immersed power transformer oil tank internal fault.
Background technique
The critical elements that power transformer is transmitted as electric energy, will be to power system power supply reliability once breaking down
It brings and seriously affects with operation stability.It is especially mounted to the large-scale power transformer of system hub site, because of its voltage etc.
Grade is high, capacity is big, structure is complicated, cost is high, is damaged due to failure and is bound to cause huge economic loss.Therefore, it is necessary to
Functional, reliable operation protective relaying device is installed according to the capacity of transformer and significance level.
The development of Protection Technology depends on the understanding to fault signature, it is considered that power transformer interior fault mainly has
Three features, first is that phase current increases, second is that spill current increases, third is that failure gas is formed.The corresponding electrical measure feature of first two,
Widely applied safeguard measure includes overcurrent protection and current differential protection, and the latter is current inside transformer short trouble
One of main protected mode.However, transformer current differential protection is primarily present two aspect defects in principle: first, becoming
Excitation surge current existing for energized circuit would potentially result in differential protection malfunction when depressor idle-loaded switching-on；Second, in face of single
When the weak failure such as circle or small turn number short circuit, because of sensitivity deficiency refused action may occur for differential protection.In consideration of it, early in previous generation
Scholars' twenties that record have invented transformer protection just to make up the deficiency of electrical quantity protection.It is protected compared to electrical quantity,
The non-ionizing energy loss for reacting on failure gas generation more fully, directly reacts the operating status of protected object, and in sensitivity
Etc. unique advantage.Although tradition machinery formula non-ionizing energy loss successfully protects ten hundreds of in the use process of last 100 years
Oil-immersed transformer, but due to there are theoretical modeling difficulty, principle defect, taking threshold value and mechanical structure dynamic by rule of thumb
Make the problems such as performance is insufficient, is increasingly difficult to meet the requirements at the higher level of current large capacity, voltage levels power transformer.Because protecting
System blackout caused by shield tripping, maloperation, Explosion of Transformer accident happen occasionally, and seriously affect the peace of electric system
Entirely, reliability service seriously threatens substation operation personnel and surrounding life and property safety of people.
When serious overheat or arc fault occurring inside oil-immersed power transformer, liquid dielectric oil will by instant vaporization,
Being decomposed to form can bubble in the height with certain volume.Under the lasting injection of failure electric energy, failure bubble inner pressure is also constantly risen
Height, simultaneously because nearby there are expanding inerts for liquid dielectric oil for fault point, the gas between failure bubble and surrounding liquid dielectric oil
Liquid interface necessarily leads to significant pressure rise, and leads to fuel tank in oil tank of transformer internal communication in the form of pressure wave
The entirety of internal oil pressure rises sharply.Further, since oil tank of transformer and vessels not under pressure, cabinet is often under the impact of internal pressure wave
Deformation occurs, cracking.On the other hand, when external short circuit failure occurs for transformer, fault point is located at transformer outlet, for
The influence of tank internal pressure is only embodied on basket vibration caused by short-circuit through current.Simultaneously as the machinery of winding is answered
Change will consume big energy, therefore the variation of oil pressure caused by the process is limited.It is similar with external fault, transformer normal operation,
Excitation surge current is that electric current flows through winding generation vibration initiation oil pressure variation.Therefore, using in transformer under different service conditions
The difference of portion's oil pressure feature can effectively screen power transformer interior fault state.
Summary of the invention
The object of the present invention is to provide a kind of transformer digital self-adapting protective device and method based on pressure characteristic,
The application of this method can reliable, sensitive, quick identification oil-immersed power transformer internal fault, and not by the shadow of excitation surge current
It rings.
To achieve the above object, the present invention adopts the following technical scheme that:
A kind of transformer digital self-adapting protective device based on pressure characteristic, comprising: transient state oil pressure feature measurement
Module, switching input module, signal condition and acquisition module, digital core module；Wherein, transient state oil pressure feature measurement mould
Block is connected with signal condition with acquisition module, signal condition and acquisition module and switching input module with digital core module
It is connected；
Oil pressure variation characteristic of the transient state oil pressure feature measurement module for different location inside measuring transformer, and export
Corresponding analog voltage/current signal；
The analog voltage/current that signal condition and acquisition module are used to receive the output of transient state oil pressure feature measurement module is believed
Number, and it is converted into the standardized digital signal that digital core module can identify, then outputting standard digital signal；
Switching input module is used to acquire the related switch amount signal that knows of needs, and output it as high level 1 or
Low level 0, the input digital signal as digital core module；
The standardized digital signal and input digital signal that digital core module is used to receive execute protection operation, complete
Standardized digital signal handles task, and then realizes relay protection function.
A further improvement of the present invention lies in that transient state oil pressure feature measurement module is sensed by several high frequency dynamic oil pressure
Device and its communications cable composition；High frequency dynamic oil pressure sensor is mounted on transformer body, high frequency dynamic oil pressure sensor end
Portion's probe is in contact with transformer insulation oil, with the oil pressure variation characteristic of measuring transformer inside different location.
A further improvement of the present invention lies in that the measurement frequency of high frequency dynamic oil pressure sensor is 20kHz, measurement error is small
In 1%, operating temperature is -45~120 DEG C, and range is -0.1~6MPa.
A further improvement of the present invention lies in that signal condition and acquisition module are by connecting terminal, signal conditioning circuit, low pass
Filter, signal sample circuit and modulus A/D conversion circuit composition；Connecting terminal is connected with signal conditioning circuit, signal tune
Reason circuit is connected with low-pass filter, and low-pass filter is connected with signal sample circuit, and signal sample circuit and modulus A/D are converted
Circuit is connected；Connecting terminal is also connected with transient state oil pressure feature measurement module, modulus A/D conversion circuit also with digital core mould
Block is connected.
A further improvement of the present invention lies in that digital core module by bus, central processing unit, timer/counter, with
Machine memory and control circuit composition；Bus includes data/address bus, address bus and control bus, realize data exchange and
Operation control；Central processing unit utilizes chip microprocessor, general purpose microprocessor or digital signal processor real-time implementation number
Signal processing；Timer/counter is used to provide timing sampling trigger signal, is formed and interrupt, protect deferred action timing；At random
Memory is for keeping in ephemeral data, in data information, calculation processes including signal condition and acquisition module input
Between result；Control circuit realizes the connection of entire digital circuit by Complex Programmable Logic Devices or field programmable gate array
And co-ordination.
A further improvement of the present invention lies in that further including the external communication interface module being connected with digital core module, people
Machine session module and switching value output module；
External communication interface module is to provide the information channel with computer communication network and telecommunicatio network；
Human-computer dialogue module is used for the informational linkage established between digital protection equipment and user；
Switching value output module controls the on-off for executing trip(ping) circuit by 0 or 1 state of output.
A further improvement of the present invention lies in that switching value output module is by photoelectric isolating device and exit relay group
At photoelectric isolating device one end is connected with digital core module, and the other end is connected with exit relay；
Human-computer dialogue module includes that compact keyboard, display screen, indicator light, button, printer interface and debugging communication connect
Mouthful.
A kind of guard method of the transformer digital self-adapting protective device based on above-mentioned pressure characteristic, including following step
It is rapid:
(1) the oil pressure variation characteristic of transient state oil pressure feature measurement module measuring transformer inside different location, and export
With analog voltage/current signal, signal condition and acquisition module receive the simulation electricity that transient state oil pressure feature measurement module exports
Pressure/current signal, and it is converted into the standardized digital signal that digital core module can identify, then outputting standard number letter
Number；Switching input module is used to acquire the related switch amount signal for needing to know, and outputs it as high level 1 or low level
0, the input digital signal as digital core module；The input digital signal and standard digital that digital core module receives are believed
More current each measuring point transient state oil pressure value p of t moment after numberms.i(t) whether reach preset protection starting threshold value pstTo determine
Whether the transformer self-adaptive protection based on pressure characteristic starts, if 1. formula is set up, active flag set enters step (2)；
pms.i(t)≥pst ①
Formula 1. in, pms.i(t) the transient state oil pressure value of i-th of measuring point of inside transformer of t moment is indicated, wherein i is 1,
2,…,N；pstIndicate protection starting threshold value；
(2) judge that transformer currently whether in idle-loaded switching-on state, is otherwise walked if so, carrying out step (3)
Suddenly (5)；
(3) idle-loaded switching-on operating pressure p is 2. calculated using formulaop.k；
Formula 2. in, TkFor idle-loaded switching-on data window length；
(4) if the idle-loaded switching-on operating pressure p being calculatedop.kMore than or equal to preset idle-loaded switching-on protection act threshold
Value pth.k, i.e. 3. formula sets up, then protection act, and tripping excision failure, package unit involution waits manual reset；
pop.k≥pth.k ③
Under the conditions of transformer excitation flow, operating pressure pop.kIt is not 0 amount of unbalance p for oneub.k, it is less than protection
Threshold value pth.k；Once air-drop is in internal short circuit fault, failure gas is generated and pressure-wave emission will lead to fuel tank internal pressure
It rises sharply, at this time pop.kIt will be greater than threshold value pth.k；Therefore, by judging whether formula is 3. true, the action behavior of protection is determined；
(5) the operating pressure p of current t moment is 4. calculated using formulaop.i:
Formula 4. in, T be data window length；
(6) compare the operating pressure p being calculatedop.iThreshold value p is acted with preset pressure protectionthSize relation,
If the operating pressure p being calculatedop.iThreshold value p is acted more than or equal to preset pressure protectionth, i.e. 5. formula sets up, then protects
Movement, tripping excision failure, package unit involution wait manual reset；
pop.i≥pth ⑤。
A further improvement of the present invention lies in that in step (1), protection starting threshold value pstIs defined as:
pst=krelpnm·max ⑥
Formula 6. in, krelFor safety factor, safety factor krelIt is 1.2；pnm.maxFor transient state under transformer normal running (operation) conditions
The maximum value of oil pressure value；
In step (3), idle-loaded switching-on data window length TkIt is selected when being adjusted with preset idle-loaded switching-on movement threshold value
Data window length is identical；Idle-loaded switching-on data window length TkIt is set as 5ms, 10ms or 20ms.
A further improvement of the present invention lies in that setting idle-loaded switching-on acts threshold value p in step (4)th.kAre as follows:
pth.k=krelpub.kmax ⑦
Formula 7. in: pub.kmaxThe injustice of fuel tank internal operating pressure in the case of the maximum pressure fluctuation generated for excitation surge current
It measures, brings the surveyed transient state oil pressure value of inside transformer measuring point when excitation surge current into formula 2., the p being calculated at this timeth.kValue is
The amount of unbalance p of fuel tank internal operating pressure in the case of the maximum pressure fluctuation generated for excitation surge currentub.kmax；
Data window length T is set as 5ms, 10ms or 20ms in step (5)；
In step (6), defines pressure protection and act threshold value pthAre as follows:
pth=krelpub.max ⑧
Formula 8. in: pub.maxFor the maximum amount of unbalance of fuel tank internal operating pressure under external most serious short circuit fault condition,
Bring the surveyed transient state oil pressure value of inside transformer measuring point when external most serious short trouble into formula 4., the p being calculated at this timeop.i
Value is the maximum amount of unbalance p of fuel tank internal operating pressure under external most serious short circuit fault conditionub.max。
Compared with prior art, the invention has the benefit that
The present invention constitutes protection using digital oil pressure information to screen power transformer interior fault compared to previous machinery
Formula non-ionizing energy loss has the advantage that first, tank internal pressure feature is normal, improper and internal former in power transformer
Pressure generation, the mechanism of variation are entirely different in the case of barrier.Once internal fault, the sharply release of failure electric energy occur for transformer
Generate have certain volume and it is interior can failure bubble, the constantly heated boosting of bubble will lead to that tank internal pressure is unilateral to rise sharply.
When external short circuit occurs, fault point is located at outside transformer, and the influence to tank internal pressure is only embodied in short circuit and passes through electricity
On basket vibration caused by flowing, the feature of limited, the positive and negative oscillation of amplitude is presented in pressure characteristic at this time.Second, pressure wave is insulating
Spread speed is up to 1.26m/ms in oil, and for geometric dimension is in the large-scale power transformer of 10m, no matter which kind of reason is drawn
The pressure characteristic variation risen, protection device capture pressure change and only need several milliseconds.Therefore, pressure characteristic structure is selected
Building protection has enough rapidities.Third, facing some low energy such as single turn or small turn number short circuit compared to electrical quantity protection
Amount failure shows under-sensitive problem when occurring, non-ionizing energy loss has advantages that the weak event of more highly sensitive reaction altogether
Barrier.The angle analysis converted from energy, Network Fault in Electrical System is by along with the conversion of failure electric energy, and non-electrical physical quantity is often
It is the direct characterization of different form energy, while inherently cumulative effect.Apparatus of the present invention can not destroy transformer
The measurement of real-time digital formula, the acquisition, operation to fuel tank internal oil pressure characteristic information are realized under the premise of existing structure integrality.
Further, use measurement frequency for 20kHz in the present invention, measurement error less than 1%, operating temperature for -45~
120 DEG C, range is the high frequency dynamic pressure transducer of -0.1~6MPa, no matter from precision or use scope can meet electric power
Inside transformer high temperature, greasy dirt, forceful electric power magnetic environment；High frequency dynamic pressure transducer is independently of electric power networks, the survey of pressure characteristic
Amount and transmission be disturbed it is smaller, also not to electric system harmonic；Data sampling and processing element is fully able to meet fast
Speed, the requirement for handling multi-path, high-frequency data in real time.
Further, traditional Buchholz relay can only be incuded oil stream flow velocity size by mechanical spring arrangement and can only be exported
Switching value information, single flow velocity amplitude often can not correct differentiating transformer area's internal and external fault, so as to cause false protection or
Person's tripping.Apparatus of the present invention by transient state oil pressure feature measurement module, switching input module, signal condition and acquisition module,
Digital core module, external communication interface module, human-computer dialogue module and switching value output module composition.Using in transformer
The oscillation of fuel tank internal oil pressure amplitude increases when portion's failure, and operates normally, oil pressure presentation under the conditions of external short circuit or excitation surge current
Amplitude is limited, periodic swinging feature, calculates the operating pressure based on multiple measuring point transient state oil pressure values, by with protection act
Threshold value compares size to judge operating status locating for transformer.When being determined as internal fault, trip signal, excision event are issued
Hinder transformer, a whole set of protective device involution.
The present invention according to protection philosophy and functional requirement to protective device monitoring, troubleshooting, human-computer dialogue, communication, from
Inspection, accident record and analysis report and debugging function, using fuel tank internal transient state oil pressure information and at different operating conditions
The pressure gap of appearance realizes quick, sensitive, the reliable examination to oil tank of transformer internal fault, and not by excitation surge current shadow
It rings.In addition, it is contemplated that oil pressure amplitude is significantly less than external short circuit failure under the conditions of excitation surge current, and intrinsic time window will affect sky
The movement speed protected under fault condition is thrown, the present invention devises the protection scheme that malfunction is adaptive, threshold value is adaptive
To improve movement speed of protection when in face of air-drop in failure.The principle of the invention is simple, device is easily achieved, will be in the past with warp
It tests and feels that the mechanical non-ionizing energy loss constituted is increased to quantitative analysis, high reliability determines, the new stage of Digital Realization,
To adapt to the requirement of current and future large capacity, voltage levels power transformer to non-ionizing energy loss " four property ".
Detailed description of the invention
Fig. 1 is the device of the invention structure principle chart.
Fig. 2 is flow chart of the invention.
Specific embodiment
Present invention will now be described in detail with reference to the accompanying drawings..
Referring to Fig. 1, the transformer self-adaptive protector based on pressure characteristic that is used in the present invention, comprising: transient state oil
Press feature measurement module, switching input module, signal condition and acquisition module, digital core module, external communication interface
Module, human-computer dialogue module and switching value output module；Wherein, transient state oil pressure feature measurement module and signal condition with adopt
Collect module to be connected, signal condition and acquisition module, switching input module, external communication interface module, human-computer dialogue module with
And switching value output module is connected with digital core module.
Transient state oil pressure feature measurement module is made of several high frequency dynamic oil pressure sensors and its communications cable, is used for
The internal oil pressure variation characteristic of measuring transformer different location, and export corresponding analog voltage/current signal.High frequency
Dynamic oil pressure sensor is mounted on transformer body, and sensor end probe is directly in contact with transformer insulation oil, to survey
The internal oil pressure variation characteristic of quantitative change depressor different location.The measurement frequency of high frequency dynamic oil pressure sensor is 20kHz, and measurement misses
For difference less than 1%, operating temperature is -45~120 DEG C, and range is -0.1~6MPa.
Signal condition and acquisition module by connecting terminal, signal conditioning circuit, low-pass filter, signal sample circuit and
Modulus A/D conversion circuit composition；Connecting terminal is connected with signal conditioning circuit, and signal conditioning circuit is connected with low-pass filter,
Low-pass filter is connected with signal sample circuit, and signal sample circuit is connected with modulus A/D conversion circuit；Connecting terminal also with it is logical
Believe that cable is connected.Signal condition and acquisition module are used to receive analog voltage/electricity of transient state oil pressure feature measurement module output
Signal is flowed, and is converted into the standardized digital signal that digital core module can identify, then outputting standard digital signal；
Switching input module is used to acquire the related switch amount signal that knows of needs, and output it as high level 1 or
Low level 0, the input digital signal as digital core module.
Digital core module is by bus, central processing unit, timer/counter, random access memory and control circuit group
At；Bus includes data/address bus, address bus and control bus, realizes data exchange and operation control；Central processing unit benefit
Digital Signal Processing is realized real-time, quickly with chip microprocessor, general purpose microprocessor or digital signal processor；Timer/meter
Number device is used to provide timing sampling trigger signal, is formed and interrupt, protect deferred action exact timing；Random access memory is for keeping in
The a large amount of ephemeral datas for needing fast exchange, data information, calculation processes including signal condition and acquisition module input
Intermediate result；Control circuit realizes entire digital circuit by Complex Programmable Logic Devices or field programmable gate array
Effectively connection and co-ordination.
The standardized digital signal and input digital signal that digital core module is used to receive execute protection operation, complete
Digital signal processing tasks command the normal operation of adjacent modules, realize data exchange and operation control, to realize that relay is protected
Protective function.
External communication interface module is realized to provide the information channel with computer communication network and telecommunicatio network
Information exchange, data sharing, remote operation and remote maintenance.
Human-computer dialogue module includes that compact keyboard, display screen, indicator light, button, printer interface and debugging communication connect
Mouthful etc., for establishing the informational linkage between digital protection equipment and user, so that operations staff is to the people of protective device
Information feedback is debugged and is obtained in work operation.
Switching value output module is made of photoelectric isolating device and exit relay, photoelectric isolating device and outlet relay
Device is connected, and for controlling the on-off for executing trip(ping) circuit by 0 or 1 state of output, realizes the action message of protection.
Referring to fig. 2, the guard method based on above-mentioned protective device, according to protection philosophy and functional requirement to protective device into
Row control, data acquisition, PERCOM peripheral communication, digital operation, logic judgment and action command execution etc. are every in an orderly manner grasps
Make, the specific steps are as follows:
(1) protective device power on or hardware reset (referred to as reset) after, system initialization is first carried out, makes entirely to protect
Device is in normal operating conditions；
(2) comprehensive self-test after powering on is executed, correctness, integrity detection are carried out to the working condition of itself, if discovery
Device defect then issues alarm signal and is latched whole device, waits technical staff's debugging, manual reset；
(3) if by self-test, data acquisition initialization is executed, and start timing sampling interruption, to save sampling to circulation
Data buffer zone carries out address distribution, and setting indicates the dynamic address pointer of current latest data, then by defined sampling week
Abort Timer assignment that phase samples control loop simultaneously enables its starting, open Sampling interrupt；
(4) the oil pressure variation characteristic of transient state oil pressure feature measurement module measuring transformer inside different location, and export
Corresponding analog voltage/current signal；Signal condition and acquisition module reception transient state oil pressure feature measurement module are defeated
Analog voltage/current signal out, and it is converted into the standardized digital signal that digital core module can identify, then export mark
Quasi- digital signal；Switching input module acquisition needs the related switch amount signal that knows, and outputs it as high level 1 or low
Level 0, the input digital signal as digital core module；The standardized digital signal and input number that digital core module receives
After word signal, temporary blocking defencive function waits sampled data buffer area to have enough data (number of one or two cycle
According to), then open and protection function；
(5) whole group initializes, and carries out operation self-test under operation, issues alarm signal simultaneously if finding device defect
It is latched whole device, waits technical staff's debugging, manual reset；
(6) if it is without failure, communication task processing is executed, sends and receives carry out data preparation for information；Include:
Collected according to the data sending request of guard method other parts related data, by communication protocol carry out communication information arrangement and
It is packaged, collating sort and task deadline is carried out to the data of data receiver buffer area；
(7) man-machine dialog process is executed, is scanned keyboard, control button, the showing in display screen data of the task, and right
Various operational orders explain and classify, and deliver corresponding task by task category and handle；
(8) judge whether protective device is in working operating mode；If not working operating mode then carries out at debugging task
It manages, return step (5) after the completion of debugging task；If being in working operating mode, (9) are entered step；
(9) differentiate active flag whether set, illustrate that protective device is having detected that possible thing before if set
Therefore disturb, enter step (11)；Otherwise (10) are entered step；
(10) each measuring point transient state oil pressure value p of more current t momentms.i(t) whether reach preset protection starting threshold value
pstWhether start to determine that the transformer self-adaptive based on pressure characteristic is protected, if formula is 1. invalid, return step (5)；If formula
1. setting up, active flag set enters step (11)；
pms.i(t)≥pst ①
Formula 1. in, pms.i(t) the transient state oil pressure value of i-th of measuring point of inside transformer of t moment is indicated, wherein i is 1,
2,…,N；pstIndicate protection starting threshold value.
In order to ensure pressure protection can start work under failure and improper disturbed conditions, protection is started into threshold value
pstIs defined as:
pst=krelpnm·max ②
Formula 2. in, krelFor safety factor, value 1.2；pnm.maxFor transient state oil pressure value under transformer normal running (operation) conditions
Maximum value.
(11) judge that transformer currently whether in idle-loaded switching-on state, if so, carrying out step (12), otherwise, carries out
Step (14)；
(12) idle-loaded switching-on operating pressure p is 3. calculated using formulaop.k
Formula 3. in, TkFor idle-loaded switching-on data window length, selected when being adjusted with preset idle-loaded switching-on movement threshold value
Data window length is identical, can choose 5ms, 10ms or 20ms as needed.
(13) if the idle-loaded switching-on operating pressure p being calculatedop.kMore than or equal to preset idle-loaded switching-on protection act door
Threshold value pth.k, i.e. 4. formula sets up, then protection act, and tripping excision failure, package unit involution waits manual reset；Otherwise it returns
It returns step (5)；
pop.k≥pth.k ④
Under the conditions of transformer excitation flow, operating pressure pop.kIt is not 0 amount of unbalance p for oneub.k, it is less than protection
Threshold value pth.k；Once air-drop is in internal short circuit fault, failure gas is generated and pressure-wave emission will lead to fuel tank internal pressure
It rises sharply, at this time pop.kIt will be greater than threshold value pth.k.Therefore, by judging whether formula is 4. true, in that case it can be decided that the action row of protection
For.
To guarantee that the transformer self-adaptive based on pressure characteristic protects the most serious pressure oscillation item generated in excitation surge current
Not malfunction under part, setting idle-loaded switching-on act threshold value pth.kAre as follows:
pth.k=krelpub.kmax ⑤
Formula 5. in: pub.kmaxThe injustice of fuel tank internal operating pressure in the case of the maximum pressure fluctuation generated for excitation surge current
It measures, brings the surveyed transient state oil pressure value of inside transformer measuring point when excitation surge current into formula 3., the p being calculated at this timeth.kValue is
The amount of unbalance p of fuel tank internal operating pressure in the case of the maximum pressure fluctuation generated for excitation surge currentub.kmax。
(14) the operating pressure p of current t moment is 6. calculated using formulaop.i:
Formula 6. in, T is data window length, the data window length phase selected when adjusting with preset protection act threshold value
Together, 5ms, 10ms or 20ms can be chosen as needed
(15) compare the operating pressure p being calculatedop.iThreshold value p is acted with preset pressure protectionthSize relation,
If the operating pressure p being calculatedop.iThreshold value p is acted more than or equal to preset pressure protectionth, i.e. 7. formula sets up, then protects
Movement, tripping excision failure, package unit involution wait manual reset；Otherwise return step (5)；
pop.i≥pth ⑦
To guarantee that the transformer self-adaptive protection based on pressure characteristic generates most tight in external most serious short trouble
Not malfunction under the conditions of weight fluctuation defines pressure protection and acts threshold value pthAre as follows:
pth=krelpub.max ⑧
Formula 8. in: pub.maxFor the maximum amount of unbalance of fuel tank internal operating pressure under external most serious short circuit fault condition,
Bring the surveyed transient state oil pressure value of inside transformer measuring point when external most serious short trouble into formula 6., the p being calculated at this timeop.i
Value is the maximum amount of unbalance p of fuel tank internal operating pressure under external most serious short circuit fault conditionub.max。
Below by taking SFSZ8-40000/110 three-phase three-winding transformer as an example, illustrate effect of the present invention, type transformer master
Want geometry and nameplate parameter as shown in table 1.
The main geometry of 1 SFSZ8-40000/110 type transformer of table and nameplate parameter
It is operated normally in view of transformer, tank internal pressure frequency of oscillation mainly collects under the conditions of external short circuit and excitation surge current
In in 100Hz, 50Hz, to take into account protection reliability and calculating the time, the long 20ms of access time window in pressure protection element,
The long 20ms of access time window in idle-loaded switching-on element.Therefore, it is 0.226kPa, pressure protection member that protection starting threshold, which is calculated,
Part acts threshold value 11.974kPa, idle-loaded switching-on element movement threshold value 1.832kPa.
Table 2 is the action situation of adaptive guard under transformer difference service condition, in figure 5 it can be seen that 1) increasing has unloaded conjunction
The adaptive guard strategy of lock protection element reliability equally with higher and sensitivity, can correctly screen short including single turn
All multi-Fault States including the failure of road, and do not influenced by excitation surge current.2) due to actively being shortened under the conditions of excitation surge current
The time window calculated is protected, while being calculated according to the maximum unbalanced pressure that excitation surge current generates and protecting threshold value, therefore from
Movement speed of Preservation tactics when in face of air-drop in this fault type of failure is adapted to significantly improve.In conclusion based on pressure
The transformer self-adaptive protection scheme of power feature has the characteristics that principle is simple, is easily achieved, while also meeting relay protection pair
The requirement of " four property ".
The action situation of adaptive guard under 2 transformer difference service condition of table
The above content is a further detailed description of the present invention in conjunction with specific preferred embodiments, and it cannot be said that
A specific embodiment of the invention is only limitted to this, for those of ordinary skill in the art to which the present invention belongs, is not taking off
Under the premise of from present inventive concept, several simple deduction or replace can also be made, all shall be regarded as belonging to the present invention by institute
Claims of submission determine scope of patent protection.
Claims (10)
1. a kind of transformer digital self-adapting protective device based on pressure characteristic characterized by comprising transient state oil pressure is special
Levy measurement module, switching input module, signal condition and acquisition module, digital core module；Wherein, transient state oil pressure feature
Measurement module is connected with signal condition with acquisition module, signal condition and acquisition module and switching input module with number
Nucleus module is connected；
Oil pressure variation characteristic of the transient state oil pressure feature measurement module for different location inside measuring transformer, and export therewith
Corresponding analog voltage/current signal；
Signal condition and acquisition module are used to receive the analog voltage/current signal of transient state oil pressure feature measurement module output,
And it is converted into the standardized digital signal that digital core module can identify, then outputting standard digital signal；
Switching input module is used to acquire the related switch amount signal for needing to know, and outputs it as high level 1 or low electricity
Flat 0, the input digital signal as digital core module；
The standardized digital signal and input digital signal that digital core module is used to receive execute protection operation, complete standard
Digital signal processing tasks, and then realize relay protection function.
2. a kind of transformer digital self-adapting protective device based on pressure characteristic according to claim 1, feature
It is, transient state oil pressure feature measurement module is made of several high frequency dynamic oil pressure sensors and its communications cable；High frequency is dynamic
State oil pressure sensor is mounted on transformer body, and high frequency dynamic oil pressure sensor end probe connects with transformer insulation oil
Touching, with the oil pressure variation characteristic of measuring transformer inside different location.
3. a kind of transformer digital self-adapting protective device based on pressure characteristic according to claim 2, feature
It is, the measurement frequency of high frequency dynamic oil pressure sensor is 20kHz, and for measurement error less than 1%, operating temperature is -45~120
DEG C, range is -0.1~6MPa.
4. a kind of transformer digital self-adapting protective device based on pressure characteristic according to claim 1, feature
It is, signal condition and acquisition module are by connecting terminal, signal conditioning circuit, low-pass filter, signal sample circuit and mould
Number A/D conversion circuit composition；Connecting terminal is connected with signal conditioning circuit, and signal conditioning circuit is connected with low-pass filter, low
Bandpass filter is connected with signal sample circuit, and signal sample circuit is connected with modulus A/D conversion circuit；Connecting terminal also with transient state
Oil pressure feature measurement module is connected, and modulus A/D conversion circuit is also connected with digital core module.
5. a kind of transformer digital self-adapting protective device based on pressure characteristic according to claim 1, feature
It is, digital core module is by bus, central processing unit, timer/counter, random access memory, read-only memory and control
Circuit composition processed；Bus includes data/address bus, address bus and control bus, realizes data exchange and operation control；Center
Processor utilizes chip microprocessor, general purpose microprocessor or digital signal processor real-time implementation Digital Signal Processing；Periodically
Device/counter is used to provide timing sampling trigger signal, is formed and interrupt, protect deferred action timing；Random access memory is for temporary
Ephemeral data is deposited, the intermediate result of data information, calculation processes including signal condition and acquisition module input；It is read-only to deposit
Reservoir is for saving data；Control circuit realizes entire number by Complex Programmable Logic Devices or field programmable gate array
The connection and co-ordination of circuit.
6. a kind of transformer digital self-adapting protective device based on pressure characteristic according to claim 1, feature
It is, further includes the external communication interface module being connected with digital core module, human-computer dialogue module and output switch parameter mould
Block；
External communication interface module is to provide the information channel with computer communication network and telecommunicatio network；
Human-computer dialogue module is used for the informational linkage established between digital protection equipment and user；
Switching value output module controls the on-off for executing trip(ping) circuit by 0 or 1 state of output.
7. a kind of transformer digital self-adapting protective device based on pressure characteristic according to claim 6, feature
It is, switching value output module is made of photoelectric isolating device and exit relay, photoelectric isolating device one end and digital core
Core module is connected, and the other end is connected with exit relay；
Human-computer dialogue module includes compact keyboard, display screen, indicator light, button, printer interface and debugging communication interface.
8. a kind of transformer digital self-adapting based on pressure characteristic as described in any one of claim 1-7 protects dress
The guard method set, which comprises the following steps:
(1) the oil pressure variation characteristic of transient state oil pressure feature measurement module measuring transformer inside different location, and output and mould
Quasi- voltage/current signals, signal condition and acquisition module receive analog voltage/electricity of transient state oil pressure feature measurement module output
Signal is flowed, and is converted into the standardized digital signal that digital core module can identify, then outputting standard digital signal；Switch
Amount input module is used to acquire the related switch amount signal that knows of needs, and outputs it as high level 1 or low level 0, as
The input digital signal of digital core module；The input digital signal that digital core module receives compares with after standardized digital signal
More current each measuring point transient state oil pressure value p of t momentms.i(t) whether reach preset protection starting threshold value pstTo determine based on pressure
Whether the transformer self-adaptive protection of power feature starts, if 1. formula is set up, active flag set enters step (2)；
pms.i(t)≥pst ①
Formula 1. in, pms.i(t) the transient state oil pressure value of i-th of measuring point of inside transformer of t moment is indicated, wherein i is 1,2 ..., N；
pstIndicate protection starting threshold value；
(2) judge that transformer currently whether in idle-loaded switching-on state, if so, carrying out step (3), otherwise, carries out step
(5)；
(3) idle-loaded switching-on operating pressure p is 2. calculated using formulaop.k；
Formula 2. in, TkFor idle-loaded switching-on data window length；
(4) if the idle-loaded switching-on operating pressure p being calculatedop.kMore than or equal to preset idle-loaded switching-on protection act threshold value
pth.k, i.e. 3. formula sets up, then protection act, and tripping excision failure, package unit involution waits manual reset；
pop.k≥pth.k ③
(5) the operating pressure p of current t moment is 4. calculated using formulaop.i:
Formula 4. in, T be data window length；
(6) compare the operating pressure p being calculatedop.iThreshold value p is acted with preset pressure protectionthSize relation, if meter
Obtained operating pressure pop.iThreshold value p is acted more than or equal to preset pressure protectionth, i.e. 5. formula sets up, then protection act,
Tripping excision failure, package unit involution wait manual reset；
pop.i≥pth ⑤。
9. a kind of transformer digital self-adapting guard method based on pressure characteristic according to claim 8, feature
It is, in step (1), protection starting threshold value pstIs defined as:
pst=krelpnm·max ⑥
Formula 6. in, krelFor safety factor, safety factor krelIt is 1.2；pnm.maxFor transient state oil pressure under transformer normal running (operation) conditions
The maximum value of value；
In step (3), idle-loaded switching-on data window length TkWith the data window selected when the movement threshold value adjusting of preset idle-loaded switching-on
Length is identical；Idle-loaded switching-on data window length TkIt is set as 5ms, 10ms or 20ms.
10. a kind of transformer digital self-adapting guard method based on pressure characteristic according to claim 8, feature
It is, in step (4), setting idle-loaded switching-on acts threshold value pth.kAre as follows:
pth.k=krelpub.kmax ⑦
Formula 7. in: pub.kmaxThe amount of unbalance of fuel tank internal operating pressure in the case of the maximum pressure fluctuation generated for excitation surge current,
Bring the surveyed transient state oil pressure value of inside transformer measuring point when excitation surge current into formula 2., the p being calculated at this timeth.kValue is excitation
Shove generation maximum pressure fluctuation in the case of fuel tank internal operating pressure amount of unbalance pub.kmax；
Data window length T is set as 5ms, 10ms or 20ms in step (5)；
In step (6), defines pressure protection and act threshold value pthAre as follows:
pth=krelpub.max ⑧
Formula 8. in: pub.maxIt, will be outer for the maximum amount of unbalance of fuel tank internal operating pressure under external most serious short circuit fault condition
When portion's most serious short trouble 4. the surveyed transient state oil pressure value of inside transformer measuring point brings formula into, the p being calculated at this timeop.iValue is
For the maximum amount of unbalance p of fuel tank internal operating pressure under external most serious short circuit fault conditionub.max。
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| CN201910376457.5A CN109980602B (en) | 2019-05-07 | 2019-05-07 | Digital self-adaptive protection device and method for transformer based on pressure characteristics |
| PCT/CN2020/088307 WO2020224537A1 (en) | 2019-05-07 | 2020-04-30 | Transformer digital adaptive protection apparatus and method based on pressure characteristics |
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| CN111751719A (en) * | 2020-06-29 | 2020-10-09 | 深圳供电局有限公司 | Method and system for judging transformer protection trip edge based on power grid fault recording diagram |
| WO2020224537A1 (en) * | 2019-05-07 | 2020-11-12 | 北京中瑞和电气有限公司 | Transformer digital adaptive protection apparatus and method based on pressure characteristics |
| CN114400615A (en) * | 2021-12-31 | 2022-04-26 | 西安交通大学 | Digital non-electric quantity protection device and method for transformer based on deflection characteristics |
| CN114861445A (en) * | 2022-05-17 | 2022-08-05 | 国网江苏省电力有限公司电力科学研究院 | Oil-immersed transformer safety protection calculation method and system |
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| CN109980602B (en) | 2020-09-01 |
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