CN205333733U

CN205333733U - Wide -range electric energy meter

Info

Publication number: CN205333733U
Application number: CN201620005992.1U
Authority: CN
Inventors: 张晓东; 闫书芳; 金伟剑; 曹晓峰; 杨国烨; 陶英浩; 何志超
Original assignee: JIANYIN CHANGYI GROUP
Current assignee: JIANYIN CHANGYI GROUP
Priority date: 2016-01-04
Filing date: 2016-01-04
Publication date: 2016-06-22
Anticipated expiration: 2026-01-04

Abstract

The utility model discloses a wide -range electric energy meter, including a set of first sampling mutual -inductor CT1 who is used for measuring the undercurrent signal, a set ofly be used for measuring the second sampling mutual -inductor CT2 of heavy current signal, an electronic switch MUX, a measurement chip and a MCU singlechip, the measurement chip signal input part pass through electronic switch MUX respectively with first sampling mutual -inductor CT1 and second sampling mutual -inductor CT2 connect, the SPI bus of MCU singlechip through having DMA transmit system with measurement chip communication connection, the MCU singlechip pass through IO mouth and electronic switch MUX and link to each other for control electronic switch MUX's switch switches. The utility model discloses a multrirange is measured, and especially the electric current below the measuring point of fundamental current 5% also can precise measurement in 1 (100) A gamut.

Description

A kind of wide magnitude electrical energy meter

Technical field

This utility model relates to a kind of wide magnitude electrical energy meter。

Background technology

At present, since 2009, the intelligent grid building-up work large area along with China is carried out, electric energy meter demand in low-pressure side is progressively strengthening, and generally electric energy meter specification is that 6～12 times according to Calibrated current determine, thus produce the electric energy meter of multiple current specification, if any plurality of specifications such as 1.5 (6) A, 1 (10) A, 5 (60) A, 10 (100) A。Owing to current specification is more, inevasible safeguard with bigger unnecessary workload in inspection table, dispensing, installation to power consumer, bring facility also to malice stealing electricity simultaneously。The electric energy meter that manufacturer produces multiple current specification for matched design simultaneously increases the difficulty such as buying, stock, delivery cycle, and product quality will also result in certain impact。

And now due to electricity consumption situation is complicated, equipment is various, is loaded with very big difference when difference, if use the electric energy meter of present single current specification, the electric energy meter Calibrated current selected is big, when electricity consumption is only small, not high enough lower than 5% accurate measurement precision of electric energy meter Calibrated current；If select electric energy meter Calibrated current little, very big once power consumption, electric energy meter it is possible to because of overload cause metering misalignment burn even。

If able to design a kind of electric energy that can mate all current specification, that just can solve above problem。But what existing electric energy meter was generally adopted in the design of metered side is all the mode singly organizing mutual inductor sample+conventional metered dose chip。Being limited by the narrow dynamic range of conventional metered dose chip (3000:1), existing design is the electric energy meter design of the wide-range current that cannot meet 1 (100) A。

Though having some producers designing corresponding wide magnitude electrical energy meter now, but still have a disadvantage in that

1) single group sampling transformer, same meter constant, although the requirement of wide-range can be reached to a certain extent are adopted。If but the selection less meter constant of upper selection of meter constant may result in and brings workload to calibrating on the contrary too slowly when examining and determine small area analysis；If selecting each pulse width that pulse width when big electric current of bigger meter constant does not reach grid company requirement should be 80ms ± 15ms。

2) if adopting two groups of sampling transformers or one group of sampling transformer and one group of sampling copper-manganese, although problem above can be solved, but the selection on sampling switching point is typically all selection and reads switching after electric current judges, the change of quick load cannot be met, exist metering blind area be likely to result in metering inaccurate。

A kind of wide magnitude electrical energy meter current channel self-adapting regulation method is the utility model proposes, it is achieved that accurate measurement in 1 (100) A current range for this。And also solve two above shortcoming。

Utility model content

This utility model purpose is that the defect existed for prior art provides a kind of wide magnitude electrical energy meter。

This utility model for achieving the above object, adopts the following technical scheme that a kind of wide magnitude electrical energy meter, including one group for measuring the first sampling transformer CT of small area analysis signal₁, one group for measuring the second sampling transformer CT of big current signal₂, electrical switch MUX, one by one with the computation chip of DMA transfer function and a MCU single-chip microcomputer with DMA transfer function；The signal input part of described computation chip by electrical switch MUX respectively with described first sample transformer CT₁With the second sampling transformer CT₂Connect；Described MCU single-chip microcomputer is by communicating to connect with the spi bus of DMA transfer function and described computation chip；Described MCU single-chip microcomputer is connected with electrical switch MUX by I/O mouth, for controlling the switch switching of electrical switch MUX。

Further, described electrical switch MUX is the electrical switch of DPDT。

This utility model compared with prior art has the advantage that

1. this utility model is multi-range measurement, and in 1 (100) A gamut, especially the measurement following electric current of point of fundamental current 5% also can accurate measurement。

2. this utility model is multi-range measurement, and meter constant can switch, and accelerates the calibrating speed of small area analysis, thus bring to calibrating convenient。

3. this utility model adopts DMA transfer technology and quick electrical switch handoff technique, the size that just can determine that electric current on the cycle (60ms) is measured at 3 electrical networks, thus being really achieved real-time electric current gear switch, decrease because of switching range band metering inaccuracy。

Accompanying drawing explanation

The circuit theory schematic diagram of Fig. 1 electric energy meter of the present utility model。

Fig. 2 current channel self-adaptative adjustment flow chart of the present utility model。

Detailed description of the invention

Shown in Fig. 1, disclose a kind of wide magnitude electrical energy meter, including the first sampling transformer CT measuring small area analysis signal of one group of 1.5 (6) A/5mA no-load voltage ratio₁11, the second sampling transformer CT measuring big current signal of one group of 10 (100) A/2mA no-load voltage ratio₂12, electrical switch MUX3, a computation chip U with DMA transfer function₁4 and a MCU single-chip microcomputer 5 with DMA transfer function；Described computation chip U₁The signal input part of 4 by electrical switch MUX3 respectively with described first sample transformer CT₁11 and second sampling transformer CT₂12 connect；Described MCU single-chip microcomputer 5 passes through the spi bus with DMA transfer function and described computation chip U₁4 communication connections；Described MCU single-chip microcomputer 5 is connected with electrical switch MUX3 by I/O mouth, for controlling the switch switching of electrical switch MUX3。

Preferably, described electrical switch MUX3 is the electrical switch of DPDT。

Fig. 2 is the method step being adjusted sampling channel in this utility model embodiment by Cutoff current size, just illustrates how to realize the switching of current channel in conjunction with the flow chart of Fig. 2 below。

Specifically comprise the following steps that

Step 101), open electric energy meter, measure in real time and start；

Step 102), MCU single-chip microcomputer controls the control pin of electrical switch MUX by I/O mouth, allows electric energy meter adopt the second sampling transformer CT2 as the measuring cell of current sample passage, and its meter constant is switched to 400imp/kWh；

Step 103), configure computation chip U₁Initial parameter, and arrange its current channel sampling, computation chip U₁An interrupt signal starting to transmit is produced with 60ms (3 grid cyclic waves)；

Step 104), MCU single-chip microcomputer waits the interrupt signal sent in real time, waiting receive interrupt signal after, MCU single-chip microcomputer priority treatment enters switching judging；

Step 105), MCU single-chip microcomputer judge the size of current value that computation chip sends；

Step 106), when MCU single-chip microcomputer determines current value more than 7.000A, MCU Single-chip Controlling electrical switch MUX continues to allow electric energy meter adopt the second sampling transformer CT₂As the measuring cell of current sample passage, and meter constant continues to be switched to 400imp/kWh；When determining current value less than or equal to 7.000A, control electrical switch MUX and make electric energy meter switching use the first sampling transformer CT₁As the measuring cell of current sample passage, and its meter constant is switched to 6400imp/kWh；

Step 107), without interrupt signal, then processed other program circuits by MCU single-chip microcomputer；

Step 108), end of run。

As follows for the change in this utility model:

No matter 1. system program flow process enters into that stage, in 60ms, real-time docking can be achieved with proprietary computation chip, solve metering switching blind area。

2. meter constant switches over pulse width when solving big electric current and can not meet the problem of requirement according to electric current, also solves the problem of calibrating overlong time when small area analysis。

The foregoing is only preferred embodiment of the present utility model, not in order to limit this utility model, all within spirit of the present utility model and principle, any amendment of making, equivalent replacement, improvement etc., should be included within protection domain of the present utility model。

Claims

1. a wide magnitude electrical energy meter, it is characterised in that include one group of first sampling transformer CT for measuring small area analysis signal₁, one group for measuring the second sampling transformer CT of big current signal₂, an electrical switch MUX, a computation chip and a MCU single-chip microcomputer；The signal input part of described computation chip by electrical switch MUX respectively with described first sample transformer CT₁With the second sampling transformer CT₂Connect；Described MCU single-chip microcomputer is by communicating to connect with the spi bus of DMA transfer function and described computation chip；Described MCU single-chip microcomputer is connected with electrical switch MUX by I/O mouth, for controlling the switch switching of electrical switch MUX。

2. a kind of wide magnitude electrical energy meter as claimed in claim 1, it is characterised in that described electrical switch MUX is the electrical switch of DPDT。