CN1426149A - Automatic low frequency (low voltage) load reducing control new mode and its synchronizing calculation method - Google Patents
Automatic low frequency (low voltage) load reducing control new mode and its synchronizing calculation method Download PDFInfo
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- CN1426149A CN1426149A CN 01138289 CN01138289A CN1426149A CN 1426149 A CN1426149 A CN 1426149A CN 01138289 CN01138289 CN 01138289 CN 01138289 A CN01138289 A CN 01138289A CN 1426149 A CN1426149 A CN 1426149A
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Abstract
This invention provides a power system low frequency (low voltage) load reduction control new mode and its setting computation method which utilizes function of df/dt (du/dt) to speed-up load cutting according to the character of dt/dt (du/dt) proportion to the system power vacancy to put forward the concept of frequency (voltage) "emergency wheel" and set up the control mode and setting computing method of low frequency reduce load "emergency wheel+basic wheel+standby wheel" which can effectively control frequency falling depth and increase the accuracy of cutting load of low frequency reduce load device and fully utilize system rotation standby volume to reduce loss by over-cut.
Description
Technical field: the invention belongs to power system stability control field.
Background technology: at present, the configuration mode of electric power system automatic low-frequency (low pressure) loadshedding equipment generally adds reserve wheel (the special wheel or the long delay wheel) by basic wheel and constitutes.Suppose that certain system's maximum power vacancy is Δ p (Δ U), the pairing frequency change rate of this power shortage mode is df/dt (du/dt), and the first run operating frequency that satisfies the UFLS scheme of this mode is f
1, the final stage operating frequency is f
n, selectively the minimum movements difference on the frequency is Δ f, then action wheel level n is:
Δt＝2Δt
1+Δt
y
Δ f in the formula
1Be the precision of frequency measurement element, Δ t
1(consider serious situation, promptly upper level has maximum positive error, and next stage has maximum negative error, so get 2 Δ f for the precision of time measurement element
1, 2 Δ t
1).
Be the frequency change value in the time Δ t, wherein df/dt is a frequency change rate, and it and system power vacancy are proportional, and Δ t is for having the optionally minimum time difference.Δ f
y, Δ t
yBe respectively frequency nargin and time margin (the low pressure off-load is similar).
In order to make the device effective action, n Δ t must move the time t of final stage action less than the first run, otherwise may cause the later several rounds also not have outlet, frequency has dropped to the unallowable degree of system, because Δ t is constant, require and guarantee the stable of system under the big power shortage mode in order to satisfy selectivity, whole automatic low-frequency (low pressure) load shedding scheme is only taked limit movement wheel level and is improved two kinds of means of first run operating frequency.Therefore such configuration mode and corresponding synchronizing calculation method thereof have several problems to be difficult to better coordination in engineering reality:
The one, the highest one of device is taken turns determining of (first run) frequency (voltage) startup value.Must consider two factors because determine device first run operating frequency (voltage) value, that is: the decline degree of depth of system frequency (voltage) the decline mode lower frequency (voltage) that should help suppressing the most serious helps making full use of system's spinning reserve capacity again.From suppressing system frequency (voltage) the decline degree of depth, first run operating frequency (voltage) is high more good more; Consider that from making full use of the system reserve capacity aspect then first run operating frequency (voltage) is low more good more.Under current schema, existing rules regulation and engineering reality all do not address this problem well.
The 2nd, respectively take turns inter-stage operating frequency (voltage) value and time-delay and be difficult to better determine.System power vacancy is excessive in order to suppress, system frequency (voltage) the decline degree of depth under the too fast mode of system frequency (voltage) pace of change, and startup frequency (voltage) difference that requires respectively to take turns inter-stage is little, and time-delay will be lacked.To satisfy the synchronizing calculation method of the most serious power shortage mode, under smaller power vacancy mode, will cause excessive and frequency (voltage) the recovery overshoot of the amount of cutting of loading like this.
The 3rd, often bigger in the engineering reality owing to there is not ideal method to suppress system frequency (voltage) the decline degree of depth on sharing of load of each wheel of device to former load shares of taking turns distribution, be difficult to better satisfy the requirement of different running method.
Above-mentioned low frequency (low pressure) load shedding control model and synchronizing calculation method thereof based on " basic wheel+reserve wheel ", the consequence that is applied to engineering reality is often: in order to satisfy the most serious system frequency (voltage) decline mode requirement, have to improve first run frequency operating value, strengthen former load controlled quentity controlled variables of taking turns, simultaneously, because the pairing frequency change speed of serious frequency decline mode is fast, total round of device also is restricted.Such control model can make system reserve capacity be not fully utilized on the one hand, very easily takes place to load on the other hand to cut, cause the overshoot that frequency (voltage) is recovered.
The mistake that automatic low-frequency (low pressure) loadshedding equipment may cause is cut and can be divided into two parts.First is: after the action of device previous round, though system frequency is bottom out, but, operating frequency that this moment, system frequency still was lower than next round cuts owing to causing the mistake that the next round action causes, though or install a certain the wheel under a certain failure condition and should move, but because the variation of operational mode, this is taken turns the load of being controlled and cuts greater than the caused mistake of the load under the account form of adjusting (or greater than system failure power shortage constantly); Second portion is that the mistake that spinning reserve capacity does not have fully startup to cause is cut (promptly when power shortage takes place, because machine unit speed regulating device has inertia, add that speed regulator action, unit output begin to be increased to unit and reach maximum output and need certain hour, therefore, might also fully not start by system's spinning reserve capacity, device has moved and has excised the load that can not excise).
In such pattern, reduce action wheel level and just must increase every load of being controlled of taking turns, the mistake of first is cut with regard to corresponding increase, and improves the mistake amount of cutting that first run operating frequency can increase second portion.
Summary of the invention: the object of the invention in order to coordinate above-mentioned relation better, improves the precision of low frequency (low pressure) load shedding exactly, and reducing loaded cuts, prevents system frequency (voltage) overshoot.
Solution to the problems described above of the present invention is:
1. propose and introduce urgent wheel notion.The characteristics that are in proportion according to frequency change rate df/dt (voltage change ratio du/dt) and system power vacancy, utilize df/dt (du/dt) to quicken cutting load and constitute new wheel level, promptly quicken to start basic wheel second during the first round and take turns and be defined as the urgent first round start basic wheel according to df/dt (du/dt) size, start basic wheel and quicken to start basic wheel during the first round second, third is taken turns and is defined as urgent second and takes turns, and the like.Like this, be that criterion has just constituted relatively independent urgent wheel with df/dt (du/dt).Under the smaller power vacancy mode, by basic wheel and reserve wheel action excision load restoration system frequency (voltage), serious power shortage mode is then suppressed the decline of system frequency (voltage) fast by urgent wheel action, then basic wheel and the reserve wheel recovery system frequency (voltage) by not being accelerated.
2. in the calculating of adjusting, it is system's common power vacancy mode that pairing mode is taken turns in basic wheel and reserve, the load total amount of its control is the maximum power vacancy that system may run into, basic wheel first run operating frequency (voltage), end are taken turns operating frequency (voltage) and are respectively taken turns frequency (voltage) difference value of inter-stage, time-delay length etc., require to determine to satisfy common power vacancy mode; Df/dt (du/dt) the startup value of urgent wheel is between the df/dt (du/dt) of common power vacancy mode and maximum power vacancy mode value, different modes between corresponding common power vacancy mode of different wheel levels and maximum power vacancy mode, promptly last df/dt that takes turns (du/dt) value is corresponding with df/dt (du/dt) value under the most serious power shortage mode.
Like this, low frequency (low pressure) load shedding control model has just become the new model of " urgent wheel+basic wheel+reserve wheel ".
In new low frequency (low pressure) the load shedding control model, because urgent wheel can effectively suppress the decline degree of depth of system frequency under the high-power vacancy (voltage), the better the most serious power shortage mode of coherent system and the different requirements of other power shortage modes to low frequency (low pressure) loadshedding equipment, thereby avoided in the proterotype cover definite value must take into account the difficult point of multitude of different ways, thereby solved preferably and be difficult to the problem better coordinated in low frequency under traditional control model (low pressure) the load shedding scheme.Simultaneously, because the mode relative fixed of basic wheel, and this mode is compared with maximum power vacancy mode, frequency change rate is less, it is longer that the first run moved for last one time of taking turns between action, so the action wheel level that can also increase device whenever takes turns the load controlled to reduce, reduce first run operating frequency so that system reserve capacity is fully used etc., therefore, such pattern can reduce the mistake amount of cutting of frequency emergency control and reduce the loss that causes thus.
What the present invention proposed quickens the pattern of the independent urgent wheel of excision load structure with df/dt (du/dt), is equally applicable to overfrequency (overvoltage) cutter.
Embodiment: according to pattern of the present invention, because basic wheel is adjusted according to common power vacancy mode (as 50% Δ P), the difficult point in the proterotype has not just existed so.In addition, according to df/dt and the proportional substantially characteristics of power shortage, from f
1To f
nTime increased by one times, therefore, can no longer consider a time restriction wheel level problem, thereby just can reduce first run operating frequency.Can reduce action wheel level though reduce first run operating frequency, but can increase the action wheel level of dividing by the time, the wheel level that makes basic wheel is more than or equal to the wheel level in the proterotype, the load of being controlled also therefore less than with the load that equals proterotype, thereby can reduce a part and cross and cut; In addition, power shortage greater than common power vacancy mode the time start excision load fast by urgent wheel, though having only of the final action of urgent wheel swung, but pairing variety of way has the n-1 wheel, so various power shortage modes all have corresponding urgent wheel to start, fast the decrease speed of blanketing frequency.The decrease speed that reduces first run operating frequency and blanketing frequency can make spinning reserve capacity be started more fully, increases generated output, cuts thereby further reduce.
Therefore, low frequency of the present invention (low pressure) load shedding control model, because urgent wheel can effectively suppress the decline degree of depth of system frequency under the high-power vacancy (voltage), the better the most serious power shortage mode of coherent system and the different requirements of other power shortage modes to low frequency (low pressure) loadshedding equipment, thereby can avoid in the proterotype cover definite value must take into account the difficult point of multitude of different ways, thereby can solve preferably and be difficult to the problem better coordinated in low frequency under traditional control model (low pressure) the load shedding scheme.Simultaneously, because the mode relative fixed of basic wheel, and this mode is compared with maximum power vacancy mode, frequency change rate is less, it is longer that the first run moved for last one time of taking turns between action, so the action wheel level that can also increase device whenever takes turns the load controlled to reduce, reduce first run operating frequency so that system reserve capacity is fully used etc., therefore, such pattern can reduce the mistake amount of cutting of frequency emergency control and reduce the loss that causes thus.
Claims (2)
1, a kind of frequency (voltage) emergency control pattern and synchronizing calculation method, its control model and calculated characteristics are to utilize frequency (voltage) rate of change size to be criterion, constitute the round that suppresses system frequency (voltage) the decline degree of depth under the high-power vacancy mode in frequency (voltage) emergency control.
2, according to described control model of claim 1 and synchronizing calculation method, the application in the overfrequency cutter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 01138289 CN1426149A (en) | 2001-12-17 | 2001-12-17 | Automatic low frequency (low voltage) load reducing control new mode and its synchronizing calculation method |
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|---|---|---|---|
| CN 01138289 CN1426149A (en) | 2001-12-17 | 2001-12-17 | Automatic low frequency (low voltage) load reducing control new mode and its synchronizing calculation method |
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| CN1426149A true CN1426149A (en) | 2003-06-25 |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100452605C (en) * | 2004-03-28 | 2009-01-14 | 广州市华电技术有限公司 | Method and system for preventing electric network from collapsing |
| CN101453121B (en) * | 2007-11-30 | 2011-06-22 | 上海市电力公司 | Low voltage deloading system for urban electric grid |
| CN102709916A (en) * | 2012-05-24 | 2012-10-03 | 浙江大学 | Low-voltage load cutting method of electric system |
| CN104218589A (en) * | 2014-09-22 | 2014-12-17 | 天津大学 | Low frequency load reduction method based on home furnishing type temperature control load |
| CN105119543A (en) * | 2015-09-22 | 2015-12-02 | 东方电机控制设备有限公司 | Control method and system for far-end line load shedding of generator set speed regulation system |
| CN106684845A (en) * | 2015-11-09 | 2017-05-17 | 中车大连电力牵引研发中心有限公司 | Train main circuit protection method and device |
| CN110867855A (en) * | 2019-11-27 | 2020-03-06 | 国网福建省电力有限公司厦门供电公司 | Voltage prediction method based on load active power and frequency response |
| CN112350329A (en) * | 2020-11-09 | 2021-02-09 | 南方电网科学研究院有限责任公司 | Frequency voltage control device and modeling method thereof |
-
2001
- 2001-12-17 CN CN 01138289 patent/CN1426149A/en active Pending
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100452605C (en) * | 2004-03-28 | 2009-01-14 | 广州市华电技术有限公司 | Method and system for preventing electric network from collapsing |
| CN101453121B (en) * | 2007-11-30 | 2011-06-22 | 上海市电力公司 | Low voltage deloading system for urban electric grid |
| CN102709916A (en) * | 2012-05-24 | 2012-10-03 | 浙江大学 | Low-voltage load cutting method of electric system |
| CN102709916B (en) * | 2012-05-24 | 2014-04-23 | 浙江大学 | Low-voltage load cutting method of electric system |
| CN104218589A (en) * | 2014-09-22 | 2014-12-17 | 天津大学 | Low frequency load reduction method based on home furnishing type temperature control load |
| CN105119543A (en) * | 2015-09-22 | 2015-12-02 | 东方电机控制设备有限公司 | Control method and system for far-end line load shedding of generator set speed regulation system |
| CN105119543B (en) * | 2015-09-22 | 2018-04-03 | 东方电机控制设备有限公司 | A kind of control method and system of the distal line removal of load of generating set governing system |
| CN106684845A (en) * | 2015-11-09 | 2017-05-17 | 中车大连电力牵引研发中心有限公司 | Train main circuit protection method and device |
| CN106684845B (en) * | 2015-11-09 | 2019-01-08 | 中车大连电力牵引研发中心有限公司 | Train main-circuit protection method and device |
| CN110867855A (en) * | 2019-11-27 | 2020-03-06 | 国网福建省电力有限公司厦门供电公司 | Voltage prediction method based on load active power and frequency response |
| CN110867855B (en) * | 2019-11-27 | 2021-05-07 | 国网福建省电力有限公司厦门供电公司 | Voltage prediction method based on load active power and frequency response |
| CN112350329A (en) * | 2020-11-09 | 2021-02-09 | 南方电网科学研究院有限责任公司 | Frequency voltage control device and modeling method thereof |
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