CN113820533A - Method for measuring effective value of alternating current signal - Google Patents
Method for measuring effective value of alternating current signal Download PDFInfo
- Publication number
- CN113820533A CN113820533A CN202111106249.7A CN202111106249A CN113820533A CN 113820533 A CN113820533 A CN 113820533A CN 202111106249 A CN202111106249 A CN 202111106249A CN 113820533 A CN113820533 A CN 113820533A
- Authority
- CN
- China
- Prior art keywords
- data
- signal
- stage
- sine wave
- wave
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/02—Measuring effective values, i.e. root-mean-square values
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Fire Alarms (AREA)
Abstract
The invention provides an effective value measuring method of alternating current signals for an electrical fire monitor, which is characterized in that alternating current periodic signals to be measured are processed by an operational amplifier and an A/D converter, half-wave sine wave signals are reserved, and the following processing is carried out on the single half-wave sine wave signal: t1: setting a certain frequency for data acquisition, and entering T2 by setting a first threshold point as a starting position of data acquisition in the data acquisition process; t2: acquiring a group of data according to the signal value and the longest and smallest time scales; t3: according to the data characteristics of different time points, carrying out abnormity judgment on a group of data acquired by the T2, if the data is judged to be abnormal, re-detecting and picking up a new half-wave sine wave, and if the data is judged to be abnormal, entering the T4; t4: and carrying out effective value calculation on the acquired effective data. The invention realizes the calculation of the effective value of the signal in a certain frequency range under the condition of not obtaining the signal frequency, greatly reduces the influence of signal interference on data processing, and provides effective basis for the electrical fire monitor to monitor whether the electrical fire occurs and equipment is damaged.
Description
Technical Field
The invention relates to a method for measuring an effective value of an alternating current signal adopted by an electrical fire monitor, belonging to the technical field of signal processing.
Background
The electric fire monitor is a multifunctional reliable measurement and control device, and can realize the traditional intelligent products with functions of an air switch and an electric leakage switch. The safety protection device has very important functions in the fields of safety electricity utilization, fire prevention, disaster prevention and the like, and is particularly suitable for safety protection of electricity utilization in schools, commercial buildings, factory workshops, trade markets, industrial and mining enterprises, national key fire-fighting units, intelligent buildings and residential districts, petrochemical industry, telecommunication, national defense departments and the like.
The residual current type electrical fire monitoring detector (fire monitoring detector for short) is the most common type of electrical fire monitor. When the residual current type electric fire monitoring detector collects the residual current of the alternating current circuit, the residual current transformer is mainly used for collecting a current signal of the alternating current circuit, and then the embedded system collects and calculates the signal to give a corresponding current value. The calculated result has a large error because the signal frequency may fluctuate within a certain range and there may be interference signals of the electric equipment or signal interference suffered by the controller itself in the line.
In order to obtain an effective value of an alternating current signal, the prior art generally adopts the following method: firstly, signal sampling is carried out, then frequency is calculated, and finally, an effective value is calculated, for example, in patent CN112147407A, "a method and a system for calculating an effective value of a fast analog quantity without being affected by frequency change", the following steps are adopted: s1: sampling the analog quantity at equal intervals in a relay protection device; s2: calculating the frequency of the analog quantity according to the sampling value of the current point; s3: judging whether the frequency of the analog quantity meets the requirement of a frequency threshold value; s4: and calculating an effective value of the analog quantity according to the judgment result of the S3. However, the above method is implemented without considering the interference factor of the actual environment, and thus the reliability of the obtained effective value is poor.
Patent CN106066429A discloses "a method for detecting effective value of ac short pulse signal", and also discloses that short pulse time detection firstly takes absolute value of sampled signal, after hysteresis comparison, a series of pulse waveforms can be obtained, the rising edge of the first pulse waveform is the starting point of measuring pulse, the falling edge of the last pulse waveform is positioned after ts time, the end point of measuring pulse is located, and the effective value of ac short pulse signal is calculated for the sum of squares of short pulse signal in the time of measuring starting point and measuring end point. It can be seen that the method is applicable to a group of signal sources consisting of a plurality of periodic short pulse sequences, and the group of signal sources have time interruptions ts therebetween, so that the applicability is poor.
Disclosure of Invention
The invention aims to provide an alternating current signal effective value measuring method for an electrical fire monitor, which can realize the calculation of a signal effective value in a certain frequency range under the condition of not obtaining signal frequency and can realize certain anti-interference capability.
The invention is implemented by the following technical scheme: an alternating current signal effective value measuring method for an electrical fire monitor is characterized in that an alternating current periodic signal to be measured is processed by an operational amplifier and an A/D converter, a half-wave sine wave signal is reserved, and the following processing is carried out on a single half-wave sine wave signal:
(1) first stage T1: setting a certain frequency for data acquisition, and entering a second stage T2 by setting a first threshold point as a starting position of data acquisition in the data acquisition process;
(2) second stage T2: acquiring a group of data according to the signal value and the longest and smallest time scales; the longest time scale is the longest time period for carrying out data acquisition on a single half-wave sine wave signal; the minimum time scale is used for carrying out data acquisition on a single half-wave sine wave signal and can ensure that the effective value of the data is calculated to meet the minimum time period required;
(3) third stage T3: according to the data characteristics of different time points, carrying out abnormity judgment on a group of data acquired at the second stage T2, if the data is judged to be abnormal, re-detecting and picking up a new half-wave sine wave, and if the data is judged to be abnormal, entering a fourth stage T4;
(4) fourth stage T4: and carrying out effective value calculation on the acquired effective data.
Preferably, the setting of the first threshold point in the first stage T1 is specifically: and identifying the starting position of data acquisition according to the characteristic that the signal of the rising edge of the half-wave sine wave is gradually increased.
Preferably, in the third stage T3, when a set of data is acquired using the longest time scale, the second threshold point is set as the end position of data acquisition, and the second threshold point identifies the end position of data acquisition according to the characteristic that the half-wave sine wave falling edge signal gradually decreases.
When the data is judged to be abnormal in the third stage T3, the data is judged to be abnormal if at least one of the following conditions is satisfied:
(a) the amount of valid data is small;
(b) the trend of the data does not conform to the waveform characteristics of a sine wave.
The invention has the beneficial effects that: the invention can directly position and collect the effective data of the alternating current signal, improve the efficiency and save time and space codes; in the data acquisition process, the acquired data is analyzed and abnormal judgment is carried out, so that the influence of signal interference on data processing is greatly reduced, and meanwhile, the accuracy of effective value calculation is greatly improved; the invention provides an effective basis for the electrical fire monitor to monitor whether an electrical fire and equipment damage occur by improving the accuracy of the effective value of the alternating current signal.
Drawings
Fig. 1 is a half-wave sine wave waveform diagram.
Fig. 2 is an abnormal waveform diagram (in the case of a small amount of valid data) of data acquisition according to an embodiment of the present invention.
Fig. 3 is an abnormal waveform diagram of data acquisition according to the embodiment of the present invention (the variation trend of the data does not conform to the waveform characteristics of a sine wave).
FIG. 4 is a plot of abnormal-free waveforms of data acquisition according to an embodiment of the present invention.
Detailed Description
Example one
The invention provides a method for measuring an effective value of an alternating current signal adopted by an electrical fire monitor, wherein an alternating current periodic signal to be measured is processed by an operational amplifier and an A/D converter, and then a half-wave sine wave signal is reserved, a wave form diagram is shown in figure 1, and a single half-wave sine wave signal is processed as follows:
(1) first stage T1: setting a certain frequency for data acquisition, setting a first threshold point as a starting position of the data acquisition in the data acquisition process, identifying the starting position of the data acquisition according to the characteristic that a half-wave sine wave rising edge signal is gradually increased, and then entering a second stage T2;
(2) second stage T2: acquiring a group of data according to the signal value and the minimum time scale;
(3) third stage T3: according to the data characteristics of different time points, performing abnormity judgment on a group of data acquired at the second stage T2, judging that the data is abnormal if the number of identified effective data is small as shown in FIG. 2, and detecting and picking up a new half-wave sine wave again until the data is judged to be abnormal, and entering a fourth stage T4 if the data is judged to be abnormal as shown in FIG. 4;
(4) fourth stage T4: and carrying out effective value calculation on the acquired effective data.
Example two
The invention provides a method for measuring an effective value of an alternating current signal adopted by an electrical fire monitor, wherein an alternating current periodic signal to be measured is processed by an operational amplifier and an A/D converter, and then a half-wave sine wave signal is reserved, a wave form diagram is shown in figure 1, and a single half-wave sine wave signal is processed as follows:
(1) first stage T1: setting a certain frequency for data acquisition, setting a first threshold point as a starting position of the data acquisition in the data acquisition process, identifying the starting position of the data acquisition according to the characteristic that a half-wave sine wave rising edge signal is gradually increased, and then entering a second stage T2;
(2) second stage T2: acquiring a group of data according to the signal value and the longest time scale, and identifying the end position of data acquisition, namely a second threshold point, according to the characteristic that the signal of the falling edge of the half-wave sine wave is gradually reduced;
(3) third stage T3: according to the data characteristics of different time points, carrying out abnormity judgment on a group of data acquired at the second stage T2, judging that the data is abnormal if the change trend of the data does not accord with the waveform characteristics of a sine wave as shown in FIG. 3, and detecting and picking up a new half-wave sine wave again until the data is judged to be abnormal, and entering a fourth stage T4 as shown in FIG. 4; (ii) a
(4) Fourth stage T4: and carrying out effective value calculation on the acquired effective data.
Claims (4)
1. A method for measuring the effective value of an alternating current signal is characterized in that an alternating current periodic signal to be measured is processed by an operational amplifier and an A/D converter, a half-wave sine wave signal is reserved, and the following processing is carried out on a single half-wave sine wave signal:
(1) first stage T1: setting a certain frequency for data acquisition, and entering a second stage T2 by setting a first threshold point as a starting position of data acquisition in the data acquisition process;
(2) second stage T2: acquiring a group of data according to the signal value and the longest and smallest time scales;
(3) third stage T3: according to the data characteristics of different time points, carrying out abnormity judgment on a group of data acquired at the second stage T2, if the data is judged to be abnormal, re-detecting and picking up a new half-wave sine wave, and if the data is judged to be abnormal, entering a fourth stage T4;
(4) fourth stage T4: and carrying out effective value calculation on the acquired effective data.
2. A method for measuring an effective value of an alternating current signal as claimed in claim 1, characterized in that said first threshold point in said first phase T1 is set specifically as follows: and identifying the starting position of data acquisition according to the characteristic that the signal of the rising edge of the half-wave sine wave is gradually increased.
3. The method according to claim 1, wherein in said third stage T3, when a set of data is acquired using the longest time scale, the second threshold point is set as the end position of data acquisition, and the second threshold point identifies the end position of data acquisition according to the characteristic that the half-wave sine wave trailing edge signal gradually decreases.
4. A method for measuring an effective value of an alternating current signal as claimed in claim 1, wherein when said third stage T3 makes an abnormal judgment on the data, the data is judged to be abnormal if at least one of the following conditions is satisfied:
(a) the amount of valid data is small;
(b) the trend of the data does not conform to the waveform characteristics of a sine wave.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111106249.7A CN113820533A (en) | 2021-09-22 | 2021-09-22 | Method for measuring effective value of alternating current signal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111106249.7A CN113820533A (en) | 2021-09-22 | 2021-09-22 | Method for measuring effective value of alternating current signal |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN113820533A true CN113820533A (en) | 2021-12-21 |
Family
ID=78915063
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111106249.7A Pending CN113820533A (en) | 2021-09-22 | 2021-09-22 | Method for measuring effective value of alternating current signal |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113820533A (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1782719A (en) * | 2004-12-02 | 2006-06-07 | 华为技术有限公司 | Method and device for measuring AC electricity |
| CN105759157A (en) * | 2016-05-13 | 2016-07-13 | 魏德米勒电联接（上海）有限公司 | Alternating current-direct current signal detection system and measuring method for alternating current signal effective value |
| CN107732924A (en) * | 2017-10-24 | 2018-02-23 | 国网山西省电力公司电力科学研究院 | Wind power plant dynamic reactive compensating method based on self-adapting detecting |
| CN110456138A (en) * | 2019-08-12 | 2019-11-15 | 宁波拓邦智能控制有限公司 | A kind of electric current detecting method, device and housed device |
| CN110632368A (en) * | 2019-08-09 | 2019-12-31 | 南京因泰莱电器股份有限公司 | Polysilicon power supply half-wave detection method |
-
2021
- 2021-09-22 CN CN202111106249.7A patent/CN113820533A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1782719A (en) * | 2004-12-02 | 2006-06-07 | 华为技术有限公司 | Method and device for measuring AC electricity |
| CN105759157A (en) * | 2016-05-13 | 2016-07-13 | 魏德米勒电联接（上海）有限公司 | Alternating current-direct current signal detection system and measuring method for alternating current signal effective value |
| CN107732924A (en) * | 2017-10-24 | 2018-02-23 | 国网山西省电力公司电力科学研究院 | Wind power plant dynamic reactive compensating method based on self-adapting detecting |
| CN110632368A (en) * | 2019-08-09 | 2019-12-31 | 南京因泰莱电器股份有限公司 | Polysilicon power supply half-wave detection method |
| CN110456138A (en) * | 2019-08-12 | 2019-11-15 | 宁波拓邦智能控制有限公司 | A kind of electric current detecting method, device and housed device |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101706527B (en) | Method for detecting arc faults based on time-frequency characteristics of high-frequency current component | |
| US5506789A (en) | Load extraction fault detection system | |
| WO2019127440A1 (en) | Method and device for handling direct current arc | |
| CN202720309U (en) | Detection and positioning system for partial discharging | |
| CN100529672C (en) | Information inspecting controller based on sensor and its inspection | |
| CN104614608A (en) | Detection device and method for low voltage parallel electric arc fault | |
| US20150137990A1 (en) | Method for Analyzing the Electricity Consumption of a Site Provided with a plurality of Electrical Devices | |
| AU2007283998B2 (en) | Method and apparatus for detecting a fault in a supply line | |
| CN109613386B (en) | Method and device for detecting misconnection of zero lines of three-phase power supply incoming line and automatic change-over switch | |
| CN104267273A (en) | Quick detection circuit and method for mains fluctuation | |
| US10958060B2 (en) | Method and device for detecting an electric arc in a photovoltaic installation | |
| CN201562949U (en) | Series-arc fault circuit breaker | |
| CN113820533A (en) | Method for measuring effective value of alternating current signal | |
| CN112485595B (en) | Power distribution network ground fault line selection protection method and device | |
| WO2009004607A2 (en) | Remote detection of discharge on a power line network | |
| CN113267666A (en) | Method for rapidly detecting AC voltage abnormity in power system | |
| CN211979065U (en) | Cable aging detection system | |
| CN110954158B (en) | Self-adaptive circuit for detecting temperature sensor and residual current transformer | |
| CN112200998A (en) | Early fire early warning method and system applied to power equipment and storage medium thereof | |
| CN103344893A (en) | Distributed cable partial discharge measuring method based on frequency conversion series resonance high-voltage holding test | |
| CN115327426A (en) | Direct-current power supply ground fault on-line detection method and system | |
| CN110988454B (en) | Method for monitoring small current by apparent power and real-time disposal | |
| WO2018198210A1 (en) | Abnormal device discrimination device, method, and program | |
| CN112595909A (en) | Method for intelligent substation detection test | |
| WO2021171303A1 (en) | A system and method for energy management of identical appliances using non-intrusive load monitoring technique |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |