CN102288814B - Real-time detection method for voltage dip - Google Patents
Real-time detection method for voltage dip Download PDFInfo
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- CN102288814B CN102288814B CN2011102210867A CN201110221086A CN102288814B CN 102288814 B CN102288814 B CN 102288814B CN 2011102210867 A CN2011102210867 A CN 2011102210867A CN 201110221086 A CN201110221086 A CN 201110221086A CN 102288814 B CN102288814 B CN 102288814B
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Abstract
The invention discloses a kind of real-time detection method of Voltage Drop, step includes: (1) to sample practical city's voltage VS; Find voltage dips point V it is low=
Wherein f is mains frequency,V is up to alternating current maximum value,T is the period where voltage dips point; (3) after finding voltage dips point,By the practical city's voltage of tension measuring circuit continuous sampling 10 times,Between be divided into 1ms; (4) the maximum value Vmax in 10 voltage is found out,And it is effective to be converted to virtual value V; When step (4) in virtual value V virtual value amp; amp; lt; When drop-off voltage V falls,Think Voltage Drop 1T,Otherwise return step is (2); When voltage effective value twice in succession is lower than drop-off voltage,Think Voltage Drop 2T,And so on,Obtain Voltage Drop periodicity. Real-time sampling city of the present invention voltage can go out the cycle time of Voltage Drop with real-time detection, can make correct processing in time after detecting Voltage Drop so as to electrical equipment, guarantee the normal operation of electrical equipment.
Description
Technical field
The present invention relates to a kind of voltage test method, be specifically related to the real-time detection method that a kind of voltage falls.
Background technology
Voltage falls and refers to that at a time the amplitude of voltage departs from suddenly normal range of operation, returns to again the phenomenon of normal level after very short a period of time.Research shows, voltage falls that problem has become that the many consumers of impact are normal, one of the most serious dynamic power quality problem of safe operation.
The atrocious weather condition is the main cause that causes that voltage falls, and it is relevant with atrocious weather (as thunderbolt, storm) that statistics shows that the voltage more than 60% falls all; The system failure, especially system is single-phase is another major reason that causes voltage to fall to earth fault, when power system transmission line breaks down, on this circuit even the power consumer over hundreds of rice still can be affected, its normal operating conditions is interfered.In addition, the serious distortion phenomenon of electric current followed while starting suddenly of some large loads (as large motor, the electric furnace arrangement for producing steel etc.) busbar voltage that also can cause this load to connect is fallen.As seen, the existence of the factor that can reach due to some impersonal forces, voltage falls phenomenon can not fundamentally be eliminated, and needs consumer in time to make correct processing, to guarantee the normal operation of consumer.
In existing definite voltage fell the method for amplitude size, the most frequently used was to obtain to fall amplitude by calculating the line voltage effective value.This method is the definition according to consecutive periods signal effective value, utilizes the computing of time domain one-period numeral root mean square to obtain the effective value of voltage.Its expression formula is:
, in formula, N is the hits in per cycle,
For time domain is sampled voltage.In reality,, in order to detect in real time the flip-flop of voltage effective value, often adopt the sliding average of one-period data sequence to calculate, its expression formula is:
Yet in the detection that voltage falls, the speed of detection speed is most important, although said method can detect the amplitude that voltage falls, but its testing process needs the time of one-period at least, even if adopted the mode of sliding average, but the real-time of this method of testing is still poor.
Summary of the invention
The object of the invention is to provide the real-time detection method that a kind of voltage falls, and adopts the method, can improve the real-time that test voltage is fallen, and the data calculated amount is little, can meet 10ms and above voltage falls detection.
For achieving the above object, the technical solution used in the present invention is: the real-time detection method that a kind of voltage falls, and its step comprises:
⑴ the actual city of sampling voltage: every 1ms starts the A/D conversion of CPU, by the tension measuring circuit real-time voltage V between civil power zero line and phase line that samples
S
⑵ find the voltage low valley point: with the real-time voltage V that records in step ⑴
SWith low-voltage V
LowRelatively, work as V
S＜V
LowThe time, be and find the voltage low valley point, otherwise return to step ⑴, described low-voltage V
Low=
, wherein f is mains frequency, V
MaximumFor the civil power maximal value, t is the voltage low valley point place time period, and t is greater than the time interval between double measurement;
⑶ after finding the voltage low valley point,, by the actual city of tension measuring circuit continuous sampling voltage 10 times, be spaced apart 1ms;
⑷ find out the maximal value V in 10 voltages that step ⑶ records
max, and be converted to effective value V
Effectively
⑸ the effective value V in step ⑷
Effectively＜drop-off voltage V
FallThe time, think that voltage falls 1T, otherwise return to step ⑵; As double voltage effective value V
EffectivelyLower than drop-off voltage V
Fall, think that voltage falls 2T, the like, obtain voltage and fall periodicity, wherein T=10ms.
In technique scheme; described tension measuring circuit is comprised of full-wave bridge rectifier circuit, reduction voltage circuit, filter capacitor and holding circuit; described full-wave bridge rectifier circuit input end is connected to respectively on the phase line and zero line of civil power; output terminal is connected with reduction voltage circuit; the reduction voltage circuit output terminal is connected with holding circuit through described filter capacitor; this holding circuit consists of 2 stabilivolt series connection, and output is connected with the A/D end of convert of CPU.
In technique scheme, the t in described step ⑵ equals the twice in the time interval.
In the present invention, in order to detect in real time voltage, fall, must measure in real time the magnitude of voltage of civil power.Civil power is that voltage is the alternating voltage of 220V, in order to use CPU, carries out the ac voltage measurement of 220V, must become DC voltage to alternating voltage, and high voltage is become low-voltage.Thereby meet the input voltage range of CPU.The alternating voltage of civil power 220V is from tension measuring circuit L and N input, L is the phase line of civil power, and N is the zero line of civil power, obtains a direct current pulsating volage after the heap full-wave rectification of passing a bridge, pass through again the voltage division processing of reduction voltage circuit of the formation of resistance R 1 and resistance R 2, obtain low dc pulse moving voltage.This low dc pulse moving voltage is through filtering capacitor filtering and diode D1, and the holding circuit of D2 is inputted the A/D input end of CPU.CPU uses timer internal to produce the Interruption of 1ms, and the A/D conversion that starts CPU is sampled to voltage, and according to formula 1, calculates actual magnitude of voltage V
S
Wherein, sample is the actual sample value that CPU carries out A/D, and resistance R 1, R2 are divider resistance, and Vref is the reference voltage level of A/D conversion, equates to get 5V with the supply voltage value of CPU here.The resolution of supposing the A/D conversion is 10, B=2
10=1024.What calculate finally is actual voltage value, and unit is volt.
Hereinbefore, in described step ⑵, the voltage low valley point refers to the minimum point of amplitude in potential pulse, low-voltage V
LowRefer to the electrical voltage point of nearly minimum point in potential pulse, have 2 this low-voltage V on the potential pulse of same period
Low, the time period of 2 correspondences is t, at this moment between the section in must have a voltage low valley point.Start continuous sampling 10 times after finding the voltage low valley point, obtain the voltage sample value 10 times, the time interval of each sampling is Interruption 1ms.Such 10 sampling times equal the cycle 10ms of voltage after rectification, guarantee in 10 samplings to sample the maximal value V in potential pulse
max, and be converted to effective value V
EffectivelyDrop-off voltage V in described step ⑸
FallFor the lower limit that voltage falls, the 40%(of definable civil power is 220 * 40%=88V), as the voltage V that samples
EffectivelyLess than this drop-off voltage V
FallAfter, represent that namely voltage falls 1T, when double voltage effective value lower than V
FallThe time, think that the voltage of 2T falls, the like, can calculate the periodicity that voltage falls.By voltage being fallen the calculating of periodicity, can detect in real time the cycle length that voltage falls, so that detecting voltage, consumer can in time make correct processing after falling, guarantee the normal operation of consumer.
Because technique scheme is used, the present invention compared with prior art has following advantages:
1, the present invention by tension measuring circuit every zero line, the phase line two ends real-time sampling voltage of 1ms at civil power, after finding low ebb voltage, obtain again the maximal value of potential pulse in this cycle through 10 samplings, and calculate effective value, if effective value is less than drop-off voltage, the voltage that namely represents one-period falls, by voltage being fallen the calculating of periodicity, can detect in real time the cycle length that voltage falls, can in time make correct processing so that consumer detects voltage after falling, guarantee the normal operation of consumer;
2, detection method real-time of the present invention is good, can meet 10ms and above voltage falls detection;
3, the inventive method can be used in different electric equipment products, by the voltage drop test, the voltage that meets electric equipment products falls immunity experiment smoothly, and then improves the safe running performance of electric equipment and the quality of electric equipment.
Description of drawings
Fig. 1 is the circuit diagram of tension measuring circuit in the embodiment of the present invention one;
Fig. 2 is the alternating voltage waveform figure of civil power 220V;
Fig. 3 is that the civil power alternating voltage waveform is by oscillogram after the rectification step-down filtering of tension measuring circuit;
Fig. 4 is civil power 220V current waveform in full-wave rectifier figure.
Embodiment
The invention will be further described below in conjunction with drawings and Examples:
Embodiment one: shown in Fig. 1～4, and the real-time detection method that a kind of voltage falls, its step comprises:
⑴ the actual city of sampling voltage: every 1ms starts the A/D conversion of CPU, by the tension measuring circuit real-time voltage V between civil power zero line and phase line that samples
S
Described tension measuring circuit is comprised of full-wave bridge rectifier circuit, reduction voltage circuit, filter capacitor and holding circuit, and as shown in Figure 1, the alternating voltage of civil power 220V is from L and N input.L is the phase line of civil power, and N is the zero line of civil power.Magnitude of voltage between L and N is alternating current 220V.Obtain a direct current pulsating volage after the heap DB107S full-wave rectification of passing a bridge, then through the dividing potential drop step-down of resistance R 1 and resistance R 2, process, obtain low dc pulse moving voltage.This low dc pulse moving voltage is through capacitor C 1 filtering and diode D1, and the A/D input end ADC0 of the holding circuit of D2 input CPU carries out the A/D sampled measurements.CPU uses timer internal to produce the Interruption of 1ms, starts the A/D conversion of CPU in Interruption, voltage shown in Figure 3 is sampled, and according to formula 1, calculate actual magnitude of voltage.
Wherein, sample is the actual sample value that CPU carries out A/D, and resistance R 1 is got 900K, and resistance R 2 is got 10K.Vref is the reference voltage level of A/D conversion, equates to get 5V with the supply voltage value of CPU here.The resolution of supposing the A/D conversion is 10, B=210=1024.What calculate according to formula 3 finally is actual voltage value, and unit is volt.
⑵ find the voltage low valley point: with the real-time voltage V that records in step ⑴
SWith low-voltage V
LowRelatively, work as V
S＜V
LowThe time, be and find the voltage low valley point, otherwise return to step ⑴, described low-voltage V
Low=
, wherein f is mains frequency, V
MaximumFor the civil power maximal value, t is the voltage low valley point place time period, and t equals the twice in the time interval;
Because timing 1ms interrupts once, and carry out the A/D sampling.Therefore, in order definitely correctly to capture the voltage low valley point in the 10ms one-period, the mistiming in Fig. 4 between time t1 and t2 must be greater than 1ms, and for one-period more definitely captures the voltage low valley point, the mistiming of getting t1 and t2 is 2ms.According to formula
Calculate between t1 and t2 the magnitude of voltage V the when mistiming is 2ms
Low=
Volt.The magnitude of voltage VS that real-time sampling arrives and 96V voltage ratio, when actual samples to magnitude of voltage think during lower than 96V and found the voltage low valley point, and note sampling number n=0.
⑶ after finding the voltage low valley point,, by the actual city of tension measuring circuit continuous sampling voltage 10 times, be spaced apart 1ms;
Have no progeny in A/D completes, preserve sample voltage value at array Value[] in, Value[0] in preserve voltage sample value for the first time, Value[1] in preserve voltage sample value for the second time, the like.
⑷ find out the maximal value in 10 voltages that step ⑶ records
, and be converted to effective value
⑸ the effective value V in step ⑷
Effectively＜drop-off voltage V
FallThe time, think that voltage falls 1T, otherwise return to step ⑵; As double voltage effective value V
EffectivelyLower than drop-off voltage V
Fall, think that voltage falls 2T, the like, obtain voltage and fall periodicity, wherein T=10ms.
After step ⑶～the ⑷ sampling calculates effective value voltage, again according to step 2, find the voltage low valley point, after finding the voltage low valley point, then according to step ⑶～⑷ sampling, calculate effective value.So continuous circulation, constantly calculate voltage effective value.During lower than U * 40%=220V * 40%=88V, think that voltage falls when voltage effective value, according to the voltage effective value and the 88V that calculate, compare.Think that the voltage of 1T falls when voltage effective value during lower than 88V.Think that the voltage of 2T falls when double voltage effective value during lower than 88V, the like, can calculate the periodicity that voltage falls.Wherein period T=10ms is 1 cycle.
Claims (3)
1. real-time detection method that voltage falls, its step comprises:
⑴ the actual city of sampling voltage: every 1ms starts the A/D conversion of CPU, by the tension measuring circuit real-time voltage V between civil power zero line and phase line that samples
S
⑵ find the voltage low valley point: with the real-time voltage V that records in step ⑴
SWith low-voltage V
LowRelatively, work as V
S＜V
LowThe time, be and find the voltage low valley point, otherwise return to step ⑴, described low-voltage V
Low=
, wherein f is mains frequency, V
MaximumFor the civil power maximal value, t is the voltage low valley point place time period, and t is greater than 1ms;
⑶ after finding the voltage low valley point,, by the actual city of tension measuring circuit continuous sampling voltage 10 times, be spaced apart 1ms;
⑷ find out the maximal value V in 10 voltages that step ⑶ records
max, and be converted to effective value V
Effectively
⑸ the effective value V in step ⑷
Effectively＜drop-off voltage V
FallThe time, think that voltage falls 1T, otherwise return to step ⑵; As double voltage effective value V
EffectivelyLower than drop-off voltage V
Fall, think that voltage falls 2T, the like, obtain voltage and fall periodicity, wherein period T=10ms.
2. the real-time detection method that falls of voltage according to claim 1; it is characterized in that: described tension measuring circuit is comprised of full-wave bridge rectifier circuit, reduction voltage circuit, filter capacitor and holding circuit; described full-wave bridge rectifier circuit input end is connected to respectively on the phase line and zero line of civil power; output terminal is connected with reduction voltage circuit; the reduction voltage circuit output terminal is connected with holding circuit through described filter capacitor; this holding circuit consists of 2 stabilivolt series connection, and output is connected with the A/D end of convert of CPU.
3. the real-time detection method that falls of voltage according to claim 1, it is characterized in that: the t in described step ⑵ equals the twice in the time interval.
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| US9588152B2 (en) * | 2013-01-09 | 2017-03-07 | Flextronics Ap, Llc | Digital signal processing method for measurement of AC voltage with power converters at light load operation |
| CN103926455A (en) * | 2013-01-10 | 2014-07-16 | 中兴通讯股份有限公司 | Method and apparatus for identification of DC input voltage transient speed |
| CN105656332B (en) * | 2016-04-06 | 2018-08-21 | 上海联矽智能科技有限公司 | A method of using rectification dead zone be low-voltage power supply |
| CN110579638B (en) * | 2019-10-12 | 2020-11-06 | 国网江苏省电力有限公司徐州供电分公司 | Kalman filtering-based dynamic voltage drop detection method for cross power supply system |
| CN113341273B (en) * | 2021-06-03 | 2023-09-05 | 广州兆和电力技术有限公司 | Broadband measurement method, device and system for ultra-high voltage direct current fault detection |
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