CN109490809B

CN109490809B - Unpaired calibration method for CT direct current loop

Info

Publication number: CN109490809B
Application number: CN201811517799.6A
Authority: CN
Inventors: 孟兴; 刘展未; 粟方斌; 瞿军; 江家勇
Original assignee: Willfar Information Technology Co Ltd
Current assignee: Willfar Information Technology Co Ltd
Priority date: 2018-12-12
Filing date: 2018-12-12
Publication date: 2020-12-25
Anticipated expiration: 2038-12-12
Also published as: CN109490809A

Abstract

The invention discloses an unpaired calibration method of a CT direct current loop, which comprises the steps of obtaining the specification of the CT direct current loop to be calibrated; acquiring N sample CTs in each specification and testing zero output errors and position errors of the sample CTs; selecting a direct current offset calibration CT; performing direct current bias calibration on all the residual CT direct current loops to be calibrated; adopting a calibration table body to carry out U on all the CT direct current loops to be calibrated_b‑I_bAnd (4) point error calibration, thereby completing calibration of all the CT direct current loops to be calibrated. According to the invention, through selection of the direct current offset calibration CT and corresponding calibration, the idea of random pairing of the CT and the metering module is realized, pairing is not required in the meter calibration process, the meter calibration of all loops can be completed by adopting the output signal of the table body, the meter calibration efficiency is extremely high, the calibration accuracy is higher, and the calibration process is simple and reliable.

Description

Unpaired calibration method for CT direct current loop

Technical Field

The invention particularly relates to an unpaired calibration method of a CT direct current loop.

Background

With the development of economic technology, communication has become an essential secondary energy source in production and life of people, and brings endless convenience to production and life of people.

The communication tower is an important component of a communication system. At present, the iron tower base station is mainly owned by a communication operator, and in order to manage electric energy of an iron tower company, an electric energy metering module needs to be added on the basis of the prior art, so that the electric energy metering of the telecommunication operator is realized. The existing common metering technology is as follows: and each loop is provided with a single loop metering module, so that metering is realized. However, in consideration of practical application scenarios, power line routing in the iron tower of each large communication operator is not completely standard: for example, four to five current lines may exist in a slightly larger base station, and the wiring is dispersed, and if one current line adopts one metering module, the construction amount is increased, and the cost is greatly increased. Therefore, the metering module with the multi-path direct current metering function can complete the multi-path metering task, one metering module can complete multi-path direct current metering, and the metering device is convenient and quick to use and relatively low in cost.

However, in the metering module with the multi-path dc metering function, the dc metering function inside the metering module generally adopts a CT (current transformer) dc current loop to sample a current signal, and the measuring ranges of the CT dc current loops are different. Before leaving the factory, each path of independent CT direct current loop needs to be calibrated, otherwise, serious errors can be generated in metering.

At present, for a multi-path CT dc current loop, the calibration method all adopts a pair calibration method: that is, for the specific CT dc current loop of the path, calibration is performed on the calibration table body according to its measurement range (for example, the measurement range of 100A or 200A). However, it is obvious that the calibration process of this method is very complicated and complex, and the efficiency is not high, and each module can only be used together with the CT during the pairing and calibration, and the flexibility is poor.

Disclosure of Invention

The invention aims to provide an unpaired calibration method of a CT direct current loop, which has the advantages of higher calibration accuracy, high calibration efficiency and simple and reliable calibration process.

The unpaired calibration method of the CT direct current loop provided by the invention comprises the following steps:

s1, acquiring the specification of a CT adopted by a CT direct current loop to be calibrated;

s2, according to the specifications of the CT obtained in the step S1, obtaining N sample CTs in each specification, and testing the zero output error and the position error of each sample CT;

s3, selecting one sample CT as a direct current offset calibration CT according to the zero output errors and the position errors of all the sample CTs obtained in the step S2;

s4, according to the zero output error of the direct current offset calibration CT selected in the step S3, performing direct current offset calibration on all the residual CT direct current loops to be calibrated;

s5, all the CT direct current loops to be calibrated are connected to a meter calibration table body, and the meter calibration table body is adopted to carry out U on all the CT direct current loops to be calibrated_b-I_bPoint error calibration is carried out, so that calibration of all CT direct current loops to be calibrated is completed; the U is_bFor the rated voltage of the DC circuit of the CT to be calibrated, I_bThe rated current of the CT direct current loop to be calibrated.

The unpaired calibration method of the CT direct current loop further comprises the following steps:

and S6, connecting the CT direct current loop calibrated in the step S5 into a calibration table body, and performing error compensation meter verification on the calibrated CT direct current loop by using the calibration table body at a preset meter verification point, so as to verify the calibration effect of the CT direct current loop.

The predetermined checklist point is (U)_b，0.1I_b)，(U_b，0.2I_b)，(U_b，0.5I_b)，(U_b，I_b) And (U)_b，1.2I_b) (ii) a The U is_bFor the rated voltage of the DC circuit of the CT to be calibrated, I_bThe rated current of the CT direct current loop to be calibrated.

And S1, outputting the CT adopted by the CT direct current loop to be calibrated at 0-4V.

The CT specification in step S1 is 50A specification, 100A specification and 200A specification.

Selecting a sample CT as the dc offset calibration CT in step S3, specifically selecting the dc offset calibration CT according to the rule described in the following table:

TABLE 1 selected rules for DC offset calibration CT

Standard output mV	Ratio of occupation of	Tolerance error mV
			4000	100％	4000±20
2000	50％	2000±10
			800	20％	800±8
400	10％	400±6
			0	0	0±5

The unpaired calibration method of the CT direct current loop realizes the idea of random pairing of the CT and the metering module through the selection of the direct current offset calibration CT and the corresponding calibration, and the table body heating output signal can be adopted to finish the calibration of all loops without pairing in the table calibration process, so that the table calibration efficiency is extremely high, the calibration accuracy is higher, the calibration process is simple and reliable, the metering module can be combined with any CT for deployment in practical application, and only the current specification parameters set by each loop are required to be matched with the CT current specification.

Drawings

FIG. 1 is a process flow diagram of the process of the present invention.

Detailed Description

FIG. 1 shows a flow chart of the method of the present invention: the unpaired calibration method of the CT direct current loop provided by the invention comprises the following steps:

in specific implementation, the CT direct current loops to be calibrated are preferably uniform in output rule, for example, the CT direct current loops to be calibrated are all output at 0-4V;

meanwhile, for the current commonly used CT of the iron tower base station, the CT specification is preferably 50A specification, 100A specification and 200A specification;

s2, according to the specifications of the CT obtained in the step S1, obtaining N (such as 10) sample CTs in each specification, and testing the zero output error and the position error of each sample CT;

s3, selecting one sample CT as a direct current offset calibration CT according to the zero output errors and the position errors of all the sample CTs obtained in the step S2; specifically, the dc offset calibration CT is selected using the rule set forth in table 2 below:

TABLE 2 schematic table of selected rules for DC offset calibration CT

s5, all the CT direct current loops to be calibrated are connected to a meter calibration table body, and the meter calibration table body is adopted to carry out U on all the CT direct current loops to be calibrated_b-I_bPoint error calibration is carried out, so that calibration of all CT direct current loops to be calibrated is completed; the U is_bFor the rated voltage of the DC circuit of the CT to be calibrated, I_bFor the rated current of the CT DC current loop to be calibrated

S6, connecting the CT direct current loop calibrated in the step S5 into a calibration table body, and adopting the calibration table body to check the calibrated CT direct current loop at a preset checking table point (preferably (U)_b，0.1I_b)，(U_b，0.2I_b)，(U_b，0.5I_b)，(U_b，I_b) And (U)_b，1.2I_b) Carry out error compensation checklist to verify CT calibration effect of the dc current loop.

Claims

1. An unpaired calibration method for a CT direct current loop comprises the following steps:

s1, acquiring the specification of the CT adopted by the CT direct current loop to be calibrated;

s2, obtaining N sample CTs according to the specifications of the CT obtained in the step S1, and testing the zero output error and the position error of each sample CT;

s3, selecting one sample CT as the DC offset calibration CT according to the zero output errors and the position errors of all the sample CTs obtained in the step S2; specifically, the DC offset calibration CT is selected by adopting the following rule:

when the standard output is 4000mV and the ratio is 100%, the allowable error is +/-20 mV;

when the standard output is 2000mV and accounts for 50%, the allowable error is +/-10 mV;

when the standard output is 800mV and accounts for 20%, the allowable error is +/-8 mV;

when the standard output is 400mV and the ratio is 10%, the allowable error is +/-6 mV;

when the standard output is 0mV and the ratio is 0%, the allowable error is +/-5 mV;

s4, according to the zero output error of the DC offset calibration CT selected in the step S3, performing DC offset calibration on all the residual CT DC current loops to be calibrated;

s5, connecting all the CT direct current loops to be calibrated to the meter calibration table body, and performing calibration on all the CT direct current loops to be calibrated by using the meter calibration table bodyU _b-I _bPoint error calibration is carried out, so that calibration of all CT direct current loops to be calibrated is completed; saidU _bIs the rated voltage of the CT direct current loop to be calibrated,I _bthe rated current of the CT direct current loop to be calibrated.

2. The method of claim 1, wherein the step of calibrating the CT DC loop further comprises:

and S6, connecting the CT direct current loop to be calibrated to a calibration table body, and performing error compensation meter verification on the calibrated CT direct current loop by using the calibration table body at a preset meter verification point, thereby verifying the calibration effect of the CT direct current loop.

3. The method according to claim 2, wherein the predetermined calibration points are (in) C & (b)U _b，0.1I _b），（U _b，0.2I _b），（U _b，0.5I _b），（U _b，I _b) And (a)U _b，1.2I _b) (ii) a SaidU _bIs the rated voltage of the CT direct current loop to be calibrated,I _bthe rated current of the CT direct current loop to be calibrated.

4. The method according to claim 1 or 2, wherein the CT DC current loop to be calibrated in step S1 has an output of 0-4V.

5. The method according to claim 1 or 2, wherein the CT specification of step S1 is 50A, 100A and 200A.