CN107621564B - 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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- CN107621564B CN107621564B CN201710800219.3A CN201710800219A CN107621564B CN 107621564 B CN107621564 B CN 107621564B CN 201710800219 A CN201710800219 A CN 201710800219A CN 107621564 B CN107621564 B CN 107621564B
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Abstract
The invention discloses a kind of water-storage static frequency changer boosting transformer differentials to protect 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, next sample sequence for participating in operation is determined further according to Fourier's material calculation and the last sample sequence for participating in Fourier's operation, and next current value for participating in Fourier's operation sample sequence is calculated using interpolation method, fourier formula calculating current amplitude is used further according to the current points that calculate；The beneficial effect that the algorithm improves computational accuracy, improves protection response speed.
Description
Technical field
This patent is related to the transformer differential protection technology under wide frequency variation range.
Background technique
Static frequency changer (Static Frequency is mostly used when running 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 is gradually increased
It is applied on motor stator by step-up transformer, motor is dragged to rated frequency until grid-connected.When static frequency changer exports electricity
When voltage-frequency rate is higher than certain specified value (such as 5Hz, herein by taking 5Hz as an example), transformer is sealed in circuit and is started to work, 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 the new technical solution of one kind is to solve the above problems.
Summary of the invention
Goal of the invention: providing a kind of water-storage static frequency changer boosting transformer differential protection amplitude arithmetic, can be in frequency
The advantages of how wide scope uses fourier formula calculating current amplitude when changing, retain differential protection fast reaction；And
Amplitude arithmetic optimizes the response speed to guarantee differential protection when frequency wide scope changes.
Technical solution: in order to achieve the above object, water-storage static frequency changer boosting transformer differential of the present invention protects amplitude
Following technical scheme can be used in algorithm:
A kind of water-storage static frequency changer boosting transformer differential protection amplitude arithmetic, which comprises 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 operation
The sample sequence of operation；
(4), the current value of next sample sequence for participating in Fourier's operation 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 operation is participated in time value and a cycle are carried out using fourier formula.
Using above-mentioned technological means, the invention has the advantages that
1, make fourier formula when frequency wide scope changes by automatic frequency tracking when frequency wide scope changes
It is applied, emerges from the rapidity of differential protection.
2, the sample sequence current value for participating in Fourier's operation is calculated by interpolation formula improves computational accuracy.
3, each Fourier's calculating cycle is calculated using different calculating points in different frequency range, to greatest extent
Fault determining time is shortened, the rapidity of protection is improved.
Detailed description of the invention
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.
Specific embodiment
It elaborates with reference to the accompanying drawings and detailed description to the embodiment of the present invention.
Incorporated by reference to shown in Fig. 3, water-storage static frequency changer boosting transformer differential protection amplitude arithmetic disclosed by the invention exists
It is carried out in controller interruption subroutine, which includes the following steps:
Step 1: calculating frequency, and real-time update 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 wave digital Frequency Measuring.With all-wave number
For word frequency measurement, the basic principle is that the time interval of two adjacent rising edges zero crossings of detection.Zero crossing judgement can pass through
The sampled value of voltage signal determines；If being respectively u by continuous two sampled values of frequency measurement signal(y-1)、u(y), then rising edge zero crossing
Rule of judgment are as follows:
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-Are as follows:
Zero crossing and u(y)Between time interval Δ T+For
As shown in Figure 1, AD sampling number between continuous two rising edge zero crossings is k, then signal period T are as follows:
T=Δ T1++k×TAD+ΔT2- (4)
Wherein Δ T1+For the time interval of first positive value and zero crossing of this period, Δ T2-For in the period the last one
The time interval of negative value and zero crossing.Update cycle value immediately after each rising edge zero crossing, is carried out using newest periodic quantity
It calculates in next step.
Step 2: determining that Fourier calculates points and material calculation according to frequency
The points N that Fourier's operation is participated in a cycle is determined according to signal period T.When 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 operation isContinuous two Fourier
It is divided between sample sequence between calculating point
Step 3: determining next ginseng according to Fourier's material calculation and the last sample sequence for participating in Fourier's operation
With the sample sequence of operation
As shown in Fig. 2, wherein kj-1For the last sample sequence for participating in Fourier's operation, m-1, m are closest to kj-1's
Front and back double sampling sequence, Δ klastFor the fractional part of last time interpolation calculation, then this sampling sequence for participating in Fourier's operation
Arrange kjFor
kjTwo sides immediate sample sequence x-1, x can determine that (int () expression takes downwards in following formula by being rounded
Whole function), Δ k is the fractional part of this interpolation calculation.
The Δ k that this Δ k calculated is calculated as next timelast。
Step 4: calculating the current value of next sample sequence for participating in Fourier's operation 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 sequencejAre as follows:
Ij=Ix-1+Δk×(Ix-Ix-1) (7)
Step 5: using fourier formula calculating current amplitude according to the current points that calculate
It is calculated according to the points for participating in Fourier's operation in current period value and a cycle using fourier formula.
Wherein IR1Indicate current value real part, II1Indicate current value imaginary part, I1Indicate current amplitude；Fu is participated in a cycle
In leaf operation points N take the 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 operation is chosen in different frequency scope are different, choose points and GPF (General Protection False when close to power frequency
Identical, the more points of selection in low frequency are chosen, so that the response time in low frequency phase failure shortens.
In signal frequency variation, AD sample frequency is remained unchanged, and is determined by calculation and is participated in Fourier's operation sampling sequence
Column, 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:
1, make fourier formula when frequency wide scope changes by automatic frequency tracking when frequency wide scope changes
It is applied, emerges from the rapidity of differential protection.
2, the sample sequence current value for participating in Fourier's operation is calculated by interpolation formula improves computational accuracy.
3, each Fourier's calculating cycle is calculated using different calculating points in different frequency range, to greatest extent
Fault determining time is shortened, the rapidity of protection is improved.
Claims (4)
1. a kind of water-storage static frequency changer boosting transformer differential protects amplitude arithmetic, which comprises 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 operation is determined according to Fourier's material calculation and the last sample sequence for participating in Fourier's operation
Sample sequence；
(4), the current value of next sample sequence for participating in Fourier's operation is calculated using the method for interpolation；
(5), fourier formula calculating current amplitude is used according to the current points that calculate, i.e., using fourier formula according to current week
The points calculating current amplitude of Fourier's operation is participated in time value and a cycle；
In the step (1),
It detects the time interval of two adjacent rising edges zero crossings: first carrying out zero crossing judgement, zero crossing judgement is believed by voltage
Number sampled value determine, that is, setting by continuous two sampled values of frequency measurement signal is respectively u(y-1)、u(y), then rising edge zero crossing judges
Condition are as follows:
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-Are as follows:
Zero crossing and u(y)Between time interval Δ T+For
；
Sampling number between continuous two rising edge zero crossings is k, then signal period T are as follows:
T=Δ T1++k×TAD+ΔT2-
Wherein Δ T1+For the time interval of first positive value and zero crossing of this period, Δ T2-For the last one negative value in the period with
The time interval of zero crossing；Update cycle value T immediately after each rising edge zero crossing, it is next using newest periodic quantity T progress
Step calculates；
In the step (2), the points N that Fourier's operation is participated in a cycle is determined according to signal period T；Close to power frequency
When, N is according to GPF (General Protection False value；Then the material calculation of Fourier's operation isContinuous two Fourier calculate adopting between point
Sample train interval is
In the step (3), kj-1For the last sample sequence for participating in Fourier's operation, m-1, m are closest to kj-1Front and back
Double sampling sequence, Δ klastFor the fractional part of last time interpolation calculation, then this sample sequence k for participating in Fourier's operationjFor
kjTwo sides immediate sample sequence x-1, x can determine that Δ k is the fractional part of this interpolation calculation by being rounded；
The Δ k that this Δ k calculated is calculated as next timelast；
In the step (4), according to x-1, the sampled value I of x sample sequencex-1、Ix, k is obtained by interpolationjSecondary sample sequence
Value IjAre as follows:
Ij=Ix-1+Δk×(Ix-Ix-1)；
Following formula is taken in current amplitude calculating in the step (5):
Wherein IR1Indicate current value real part, II1Indicate current value imaginary part, I1Indicate current amplitude；Fourier is participated in a cycle
Operation 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.
2. water-storage static frequency changer boosting transformer differential as described in claim 1 protects amplitude arithmetic, which is characterized in that institute
State step (1) into (5) to the calculating of current amplitude in the controller break subprogram in carry out.
3. water-storage static frequency changer boosting transformer differential as described in claim 1 protects amplitude arithmetic, which is characterized in that
The points that Fourier's operation is chosen in different frequency scope are different, and it is identical as GPF (General Protection False selection to choose points when close to power frequency,
More points are chosen in low frequency, so that the response time in low frequency phase failure shortens.
4. water-storage static frequency changer boosting transformer differential as claimed in claim 3 protects amplitude arithmetic, which is characterized in that
When signal frequency changes, sample frequency is remained unchanged, and is determined by calculation and is participated in Fourier's operation sample sequence, and interpolation obtains
Participate in the data that Fourier calculates.
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| CN107621564B true CN107621564B (en) | 2019-09-24 |
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| 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 |
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 |
-
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 |
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