CN107621564A - A kind of water-storage static frequency changer boosting transformer differential protection amplitude arithmetic - Google Patents
A kind of water-storage static frequency changer boosting transformer differential protection amplitude arithmetic Download PDFInfo
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- CN107621564A CN107621564A CN201710800219.3A CN201710800219A CN107621564A CN 107621564 A CN107621564 A CN 107621564A CN 201710800219 A CN201710800219 A CN 201710800219A CN 107621564 A CN107621564 A CN 107621564A
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Abstract
The invention discloses a kind of water-storage static frequency changer boosting transformer differential protection amplitude arithmetic.By motor side voltage real-time frequency measurement and update, and determine that Fourier calculates points and material calculation according to electric voltage frequency, the sample sequence of next participation computing is determined further according to Fourier's material calculation and the last sample sequence for participating in Fourier's computing, and next current value for participating in Fourier's computing sample sequence is calculated using interpolation method, use fourier formula calculating current amplitude further according to the current points that calculate；The algorithm improves computational accuracy, improves the beneficial effect of protection response speed.
Description
Technical field
This patent is related to the transformer differential protection technology under wide frequency variation range.
Background technology
Static frequency changer (Static Frequency are mostly used when being run under large pumped storage power plant pump operating condition
Converter, SFC) Starting mode, the static frequency changer using the high structure of height is the voltage signal that output frequency gradually increases
It is applied to by step-up transformer on motor stator, motor is dragged to rated frequency until grid-connected.When static frequency changer exports electricity
When voltage-frequency rate is higher than certain setting (such as 5Hz, herein by taking 5Hz as an example), transformer is sealed in loop and started working, therefore in motor
In start-up course, transformer operating frequency range is very wide, and the mode that current amplitude calculates in conventional differential protection mode is no longer suitable
With.
Therefore, it is desirable to provide a kind of new technical scheme is to solve the above problems.
The content of the invention
Goal of the invention：A kind of water-storage static frequency changer boosting transformer differential protection amplitude arithmetic is provided, can be in frequency
How wide scope use fourier formula calculating current amplitude when changing, the advantages of reservation differential protection fast reaction；And
Amplitude arithmetic optimizes to ensure the response speed of differential protection when frequency wide scope changes.
Technical scheme：In order to achieve the above object, water-storage static frequency changer boosting transformer differential protection amplitude of the present invention
Algorithm can use following technical scheme：
A kind of water-storage static frequency changer boosting transformer differential protection amplitude arithmetic, it is characterised in that comprise the following steps：
(1) frequency, and real-time update, are calculated by transformer secondary voltage；
(2), determine that Fourier calculates points and material calculation according to frequency；
(3) next participation, is determined according to Fourier's material calculation and the last sample sequence for participating in Fourier's computing
The sample sequence of computing；
(4) current value of next sample sequence for participating in Fourier's computing, is calculated using the method for interpolation；
(5) fourier formula calculating current amplitude, is used according to the current points that calculate, for current amplitude according to current week
The points that Fourier's computing is participated in time value and a cycle are carried out using fourier formula.
Using above-mentioned technological means, it is an advantage of the invention that：
1st, when frequency wide scope changes by automatic frequency tracking fourier formula when frequency wide scope changes
Applied, emerge from the rapidity of differential protection.
2nd, the sample sequence current value for participating in Fourier's computing calculates raising computational accuracy by interpolation formula.
3rd, each Fourier's calculating cycle is calculated using different calculating points in different frequency range, to greatest extent
Fault determining time is shortened, improves the rapidity of protection.
Brief description of the drawings
Fig. 1 is all-wave digital Frequency Measuring schematic diagram
Fig. 2 is the interpolation calculation between Fourier's calculating point and sampled point
Fig. 3 is interruption subroutine flow chart.
Embodiment
Embodiments of the invention are elaborated with reference to the accompanying drawings and detailed description.
Incorporated by reference to shown in Fig. 3, water-storage static frequency changer boosting transformer differential protection amplitude arithmetic disclosed by the invention exists
Carried out in controller interruption subroutine, the algorithm comprises the following steps：
The first step：Frequency, and real-time update are calculated by transformer secondary voltage (motor set end voltage)
Digital Frequency Measuring mode has the modes such as all-wave digital Frequency Measuring, half-wave digital Frequency Measuring, 1/4 ripple digital Frequency Measuring.With all-wave number
Exemplified by word frequency measurement, its general principle is to detect the time interval of two adjacent rising edges zero crossings.Zero crossing judges to pass through
The sampled value of voltage signal determines；If it is respectively u by continuous two sampled values of frequency measurement signal(y-1)、u(y), then rising edge zero crossing
Rule of judgment is：
By the sampling period linear process, if TADFor signal sampling period, sampled value u is obtained(y-1)Between zero crossing
Time interval Δ T-For：
Zero crossing and u(y)Between time interval Δ T+For
As shown in figure 1, the AD sampling numbers between continuous two rising edge zero crossings are k, then signal period T is：
T=Δs T1++k×TAD+ΔT2- (4)
Wherein Δ T1+It it is this cycle first on the occasion of the time interval with zero crossing, Δ T2-For in the cycle last
The time interval of negative value and zero crossing.The update cycle is worth immediately after each rising edge zero crossing, is carried out using newest periodic quantity
Calculate in next step.
Second step：Determine that Fourier calculates points and material calculation according to frequency
Determined to participate in the points N of Fourier's computing in a cycle according to signal period T.During close to power frequency, N is according to routine
Value is protected, when T is larger, N accordingly also takes bigger value.Then the material calculation of Fourier's computing isContinuous two Fourier
Calculate point between sample sequence at intervals of
3rd step：Next ginseng is determined according to Fourier's material calculation and the last sample sequence for participating in Fourier's computing
With the sample sequence of computing
As shown in Fig. 2 wherein kj-1For the last sample sequence for participating in Fourier's computing, m-1, m are closest to kj-1's
Front and rear double sampling sequence, Δ klastFor sampling sequence of the fractional part of last time interpolation calculation, then this participation Fourier's computing
Arrange kjFor
kjTwo sides immediate sample sequence x-1, x can determine that (int () represents to take downwards in below equation by rounding
Whole function), Δ k is the fractional part of this interpolation calculation.
The Δ k that this Δ k calculated calculates as next timelast。
4th step：The current value of next sample sequence for participating in Fourier's computing is calculated using the method for interpolation
According to x-1, the sampled value I of x sample sequencex-1、Ix, k is obtained by interpolationjThe value I of secondary sample sequencejFor：
Ij=Ix-1+Δk×(Ix-Ix-1) (7)
5th step：Fourier formula calculating current amplitude is used according to the current points that calculate
Points according to Fourier's computing is participated in current period value and a cycle are calculated using fourier formula.
Wherein IR1Represent current value real part, II1Represent current value imaginary part, I1Represent current amplitude；Fu is participated in a cycle
In leaf computing points N take N in second step, i (j) to take the operation result I in the 4th stepj, wherein j=0~N-1.
The points that Fourier's computing is chosen in the range of different frequency are different, close to selection points and GPF (General Protection False during power frequency
Choose identical, the more points of selection in low frequency so that shorten in the response time of low frequency phase failure.
When signal frequency changes, AD sample frequencys keep constant, determine that participating in Fourier's computing samples sequence by calculating
Row, and interpolation obtains and participates in the data that Fourier calculates.
Water-storage static frequency changer boosting transformer differential protection amplitude arithmetic proposed by the invention has following obvious excellent
Point:
1st, when frequency wide scope changes by automatic frequency tracking fourier formula when frequency wide scope changes
Applied, emerge from the rapidity of differential protection.
2nd, the sample sequence current value for participating in Fourier's computing calculates raising computational accuracy by interpolation formula.
3rd, each Fourier's calculating cycle is calculated using different calculating points in different frequency range, to greatest extent
Fault determining time is shortened, improves the rapidity of protection.
Claims (9)
1. a kind of water-storage static frequency changer boosting transformer differential protection amplitude arithmetic, it is characterised in that comprise the following steps：
(1) frequency, and real-time update, are calculated by transformer secondary voltage；
(2), determine that Fourier calculates points and material calculation according to frequency；
(3) next participation computing, is determined according to Fourier's material calculation and the last sample sequence for participating in Fourier's computing
Sample sequence；
(4) current value of next sample sequence for participating in Fourier's computing, is calculated using the method for interpolation；
(5) fourier formula calculating current amplitude, is used according to the current points that calculate, for current amplitude according to current period value
Carried out with the points that Fourier's computing is participated in a cycle using fourier formula.
2. water-storage static frequency changer boosting transformer differential protection amplitude arithmetic as claimed in claim 1, it is characterised in that institute
State in step (1),
Detect the time interval of two adjacent rising edges zero crossings；Zero crossing judges；Determined by the sampled value of voltage signal；If
It is respectively u by continuous two sampled values of frequency measurement signal(y-1)、u(y), then rising edge zero crossing Rule of judgment be：
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By the sampling period linear process, if TADFor signal sampling period, sampled value u is obtained(y-1)Time between zero crossing
Interval delta T-For：
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AD sampling numbers between continuous two rising edge zero crossings are k, then signal period T is：
T=Δs T1++k×TAD+ΔT2-
Wherein Δ T1+It it is this cycle first on the occasion of the time interval with zero crossing, Δ T2-For last negative value in the cycle with
The time interval of zero crossing；The update cycle is worth immediately after each rising edge zero crossing, is carried out in next step using newest periodic quantity
Calculate.
3. water-storage static frequency changer boosting transformer differential protection amplitude arithmetic as claimed in claim 2, it is characterised in that institute
State in step (2), determined to participate in the points N of Fourier's computing in a cycle according to signal period T；During close to power frequency, N according to
GPF (General Protection False value；Then the material calculation of Fourier's computing isContinuous two Fourier are calculated between the sample sequence between point
It is divided into
4. water-storage static frequency changer boosting transformer differential protection amplitude arithmetic as claimed in claim 3, it is characterised in that institute
State in step (3), kj-1For the last sample sequence for participating in Fourier's computing, m-1, m are closest to kj-1Front and rear secondary adopt
Sample sequence, Δ klastFor sample sequence k of the fractional part of last time interpolation calculation, then this participation Fourier's computingjFor
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The Δ k that this Δ k calculated calculates as next timelast。
5. water-storage static frequency changer boosting transformer differential protection amplitude arithmetic as claimed in claim 4, it is characterised in that institute
State in step (4), according to x-1, the sampled value I of x sample sequencex-1、Ix, k is obtained by interpolationjThe value I of secondary sample sequencej
For：
Ij=Ix-1+Δk×(Ix-Ix-1)。
6. water-storage static frequency changer boosting transformer differential protection amplitude arithmetic as claimed in claim 5, it is characterised in that institute
State current amplitude calculating in step (5) and take below equation：
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Wherein IR1Represent current value real part, II1Represent current value imaginary part, I1Represent current amplitude；Fourier is participated in a cycle
Computing points N takes the N in step (2), i (j) to take the operation result I in step (4)j, wherein j=0~N-1.
7. water-storage static frequency changer boosting transformer differential protection amplitude arithmetic as claimed in claim 1, it is characterised in that institute
State calculating of the step (1) into (6) to current amplitude in the controller break subprogram in carry out.
8. water-storage static frequency changer boosting transformer differential protection amplitude arithmetic as claimed in claim 6, it is characterised in that
The points that Fourier's computing is chosen in the range of different frequency are different, identical with GPF (General Protection False selection close to points are chosen during power frequency,
More points are chosen in low frequency so that shorten in the response time of low frequency phase failure.
9. water-storage static frequency changer boosting transformer differential protection amplitude arithmetic as claimed in claim 8, it is characterised in that
When signal frequency changes, AD sample frequencys keep constant, determine to participate in Fourier's computing sample sequence by calculating, and interpolation obtains
The data of Fourier's calculating must be participated in.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113054627A (en) * | 2021-03-03 | 2021-06-29 | 中国电力科学研究院有限公司 | Body differential protection method and device of static frequency converter |
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| JPS63131070A (en) * | 1986-11-19 | 1988-06-03 | Yokogawa Electric Corp | Current detection circuit |
| CN104393809A (en) * | 2014-11-24 | 2015-03-04 | 哈尔滨工业大学 | Pumped storage group low-speed position detection method applicable to SCR static frequency converter |
| JP5826955B1 (en) * | 2015-01-29 | 2015-12-02 | 根岸 正子 | Low voltage circuit diagnosis system and program |
| CN105352471A (en) * | 2015-11-30 | 2016-02-24 | 云南电网有限责任公司电力科学研究院 | Transformer winding state diagnosis method |
| CN105675962A (en) * | 2016-03-02 | 2016-06-15 | 国网上海市电力公司 | Voltage and current sampling method for on-line monitoring of transformer winding state |
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2017
- 2017-09-07 CN CN201710800219.3A patent/CN107621564B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63131070A (en) * | 1986-11-19 | 1988-06-03 | Yokogawa Electric Corp | Current detection circuit |
| CN104393809A (en) * | 2014-11-24 | 2015-03-04 | 哈尔滨工业大学 | Pumped storage group low-speed position detection method applicable to SCR static frequency converter |
| JP5826955B1 (en) * | 2015-01-29 | 2015-12-02 | 根岸 正子 | Low voltage circuit diagnosis system and program |
| CN105352471A (en) * | 2015-11-30 | 2016-02-24 | 云南电网有限责任公司电力科学研究院 | Transformer winding state diagnosis method |
| CN105675962A (en) * | 2016-03-02 | 2016-06-15 | 国网上海市电力公司 | Voltage and current sampling method for on-line monitoring of transformer winding state |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113054627A (en) * | 2021-03-03 | 2021-06-29 | 中国电力科学研究院有限公司 | Body differential protection method and device of static frequency converter |
| CN113054627B (en) * | 2021-03-03 | 2022-08-16 | 中国电力科学研究院有限公司 | Body differential protection method and device of static frequency converter |
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| CN107621564B (en) | 2019-09-24 |
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