CN207557335U - For the current sampling circuit of three-phase electric energy meter - Google Patents
For the current sampling circuit of three-phase electric energy meter Download PDFInfo
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- CN207557335U CN207557335U CN201721863032.XU CN201721863032U CN207557335U CN 207557335 U CN207557335 U CN 207557335U CN 201721863032 U CN201721863032 U CN 201721863032U CN 207557335 U CN207557335 U CN 207557335U
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Abstract
For the current sampling circuit of three-phase electric energy meter, include the both ends of current sampling signal output, the current sampling signal exports one end and connects resistance Rc1 one end, resistance Rc2 one end respectively, the current sampling signal output other end connects resistance Rc3 one end, resistance Rc4 one end, the resistance Rc2 other ends, resistance Rc3 other ends ground connection respectively.Electric energy meter is enhanced using this circuit and resists high current (overload) in short-term and the ability of pulse current, thoroughly solves the problems, such as that electric energy meter is prevented diving and flies away, using being without fear of an attack from the rear, be effectively guaranteed the normal operation of electric energy meter;Improve accuracy, stability and the reliability of three-phase electric energy meter gauging of products;Be conducive to power department preferably electrical management, reasonably carry out power scheduling;Pcb board usable floor area and space have been saved, has saved national resources, has reduced unnecessary waste, has significantly reduced the cost of product, while has improved the quality, service life and competitiveness of product.
Description
Technical field
The utility model belongs to electronic electricity meter technical field, and in particular to for the current sampling circuit of three-phase electric energy meter.
Background technology
Three-phase electric energy meter, as measuring the tool of the electric energy of voltage output, the quilt of every field in real life
Extensive use.Load consumption is recorded to realize, current sampling circuit can be all used in the internal structure of three-phase electric energy meter.
Currently used three-phase electric energy meter current sampling circuit is as shown in Figure 1, utilize three-phase electric energy meter internal current mutual inductance
The secondary current sampled signal line input socket JB both ends of device connect inductance LB1 and inductance LB2, LB2 points of inductance LB1, inductance respectively
It is not connect with resistance RB3, resistance RB6, the connecting line, inductance LB2 in inductance LB1 and resistance RB3 are with resistance RB6's
The multiple capacitances of parallel connection, resistance, multiple parallel circuits are specially on connecting line:Circuit that capacitance CB1 connects with capacitance CB2, resistance
The circuit that RB1, resistance RB2, resistance RB7 connect with resistance RB8;In the resistance RB3 other ends, the Indirect Electro of the resistance RB6 other ends
Hold the circuit that CB3 connects with capacitance CB4.LB1 and LB2 uses patch magnetic bead in entire circuit;Capacitance CB1 and capacitance CB2, capacitance
CB3 and capacitance CB4 is patch capacitor, plays the role of High frequency filter;Resistance RB1, resistance RB2, resistance RB3, resistance RB6, electricity
RB7, resistance RB8 composition current sample network are hindered, but this circuit has the disadvantage that:
1. the precision (require temperature drift is small, accuracy is high) of couple sampling resistor RB1, RB2 are more demanding, once selection is not
When being easy for causing electric energy meter to occur, error polarization is overproof or even phenomenon of flying away.The reason is that in larger power consumer especially
Be short-term operation load in conventional load such as:
1), the quick travel motor of machine tool beam elevator, knife rest, gate motor etc.;
2), short-term operation load, such as crane, elevator, driving, electric welding machine repeatedly;
3), the dynamic load in specific load, such as rolling mill, electric automobile charging pile for another example;
4), impact load, such as electric furnace arrangement for producing steel, high ferro electric locomotive;
Electric power is used in above-mentioned machine or equipment, makes the three-phase electric energy meter of power consumer need to consider in current sampling circuit
The processing of high current or pulse current impact in short-term, if sampling resistor is to use common film patch resistance, it is difficult to
Have the function that anti-high current in short-term or pulse current impact.It is recognised that especially sampling resistor RB1, RB2 two from circuit
A precision resistance needs bear maximum electric current.By for a long time in short-term after high current or pulse current repeat impact, patch
Sheet resistance resistance value often generates large change (such as resistance value increase), and some is even damaged and opened a way;Caused by direct result be exactly
Total resistance value of sampling resistor group under in parallel reduces, final so that the sampled signal voltage at IBP and IPN both ends increases, so as to lead
It causes electric energy meter polarization overproof or even flies away.
2. the inductance LB1 and inductance LB2 in the current signal input of current sampling circuit are for patch magnetic bead (inductance)
Play the role of High frequency filter, but this set has not been often to high current in short-term or pulse current, in reality
Seldom there is a situation where high-frequency voltage signal;Capacitance CB1 and capacitance CB2, capacitance CB3 and capacitance in current sampling circuit simultaneously
CB4 plays the role of High frequency filter, and setting can not realize two inductance of High frequency filter function, set multiple capacitances and resistance
High frequency filter function is used to implement, there are the wastes of element setting, increase wiring cost and process so that entire electric energy meter
It is higher to manufacture cost.
Therefore it needs to be improved the current sampling circuit of traditional three-phase electric energy meter.
Utility model content
The purpose of this utility model is to solve the above-mentioned problems, to provide a kind of current sample electricity for three-phase electric energy meter
Road.
In order to reach above-mentioned purpose of utility model, the utility model uses following technical scheme:
For the current sampling circuit of three-phase electric energy meter, include the both ends of current sampling signal output, the current sample
Signal exports one end and connects resistance Rc1 one end, resistance Rc2 one end respectively, and the current sampling signal output other end connects respectively
Connecting resistance Rc3 one end, resistance Rc4 one end, the resistance Rc2 other ends, resistance Rc3 other ends ground connection.
Further, the resistance Rc2 and resistance Rc3 selects thick-film resistor.
Further, the thick-film resistor is ceramic column thick-film resistor.
Further, the resistance Rc2 other ends, the resistance Rc1 other ends are connect respectively with a capacitance CC7 both ends.
Further, the resistance Rc3 other ends, the resistance Rc4 other ends are connect respectively with a capacitance CC9 both ends.
Further, the capacitance CC7, capacitance CC9 use patch capacitor.
Further, the capacitance CC7, capacitance CC9 use precision as ± 5%, patch capacitor of NPO materials.
Further, the capacitance CC7, capacitance CC9 using same size capacitance and/or, the capacitance CC7, capacitance
The value range of CC9 is 22nF-33nF.
Further, the resistance Rc2, resistance Rc3 use the resistance value of same size;And/or the resistance Rc2, resistance
Between 5.1 Ω -7.5 Ω of Rc3 value ranges.
Further, the resistance Rc1, resistance Rc43 use the resistance value of same size;And/or the resistance Rc1, electricity
Between resistance Rc4 value range 1k Ω -1.2k Ω.
Compared with prior art, advantageous effect is the utility model:
1st, electric energy meter is enhanced using the circuit of the utility model and resists high current (overload) in short-term and the ability of pulse current,
It thoroughly solves the problems, such as that electric energy meter is prevented diving to fly away, using being without fear of an attack from the rear, is effectively guaranteed the normal operation of electric energy meter;
2nd, accuracy, stability and the reliability of three-phase electric energy meter gauging of products are improved;
3rd, be conducive to power department preferably electrical management, particularly grasp the load condition of user and bearing for bus
Lotus situation reasonably carries out power scheduling;
4th, compared to traditional circuit, component is less used by this circuit, has saved pcb board usable floor area and space, saves
About national resources, reduces unnecessary waste, significantly reduces the cost of product, at the same improve product quality,
Service life and competitiveness.
Description of the drawings
Fig. 1 is existing three-phase electric energy meter current sampling circuit figure;
Fig. 2 is the three-phase electric energy meter current sampling circuit figure of the utility model;
Fig. 3 is the three-phase electric energy meter current sample schematic diagram of the utility model.
Specific embodiment
Explanation is further described to the technical solution of the utility model below by specific embodiment.
Present embodiment discloses the current sampling circuits for three-phase electric energy meter, and as shown in Figures 2 and 3, circuit includes electricity
The both ends of sampled signal output are flowed, the current sampling signal exports one end and connects resistance Rc1 one end, resistance Rc2 one end respectively,
The current sampling signal output other end connects resistance Rc3 one end, resistance Rc4 one end respectively, the resistance Rc2 other ends,
The resistance Rc3 other ends are grounded.
In the present embodiment, resistance Rc2 and resistance Rc2 Ceramics column thick-film resistors.
As a kind of preferred embodiment, can also the resistance Rc2 other ends, the resistance Rc1 other ends respectively with
One capacitance CC7 both ends connect and/or, the resistance Rc3 other ends, the resistance Rc4 other ends are connect respectively with a capacitance CC9 both ends.
Wherein, capacitance CC7 uses patch capacitor, and capacitance CC9 also uses patch capacitor.
This current sampling circuit carries out height using being connected in parallel with a capacitor by the sampling resistor of current sampling signal output terminal
Frequency filters, without setting multiple capacitances as traditional sampling circuit.In addition sampling resistor RC2 and RC3 are selected into temperature coefficient
The ceramic column thick-film resistor of small and anti-high current (overload) in short-term and the ability of pulse current by force is (around metal outside ceramic body
Film), you can resistance is avoided even to damage and the generation of open fault, so that it is guaranteed that the quality with raising electric energy meter.This electricity
Traditional film resistor is changed to columnar ceramic thick-film resistor advantage by current circuit:Temperature drift is small, temperature coefficient is good, resists electricity big in short-term
The ability for flowing (overload) and pulse current is strong, if using column MELF types ceramic thick film resistor (around metal film outside ceramic body)
With stronger impact resistance.
As shown in figure 3, electric current, after current transformer, current signal enters electricity by the both ends that current sampling signal exports
Stream is finally entered computation chip, impact resistance is effectively increased using this circuit, ensure that electric energy meter metering using circuit
Accuracy, stability and reliability.
The key technical indexes that the present embodiment is used in experiment test for:
1), AC voltage test:Line-to-earth voltage 4kV;
2), impulse test:Line-to-earth voltage 6kV;
3), elementary error:0.2Ib~Imax:±0.3;
0.05Ib~0.1Ib:±0.5;
4), external constant magnetic field sensing influences:In error variance limit value ± 1.0;
5), power frequency magnetic field influences:In error variance limit value ± 2.0.
Resistance Rc2, the model specification of resistance Rc3, resistance value are identical in the present embodiment, 5.1 Ω -7.5 Ω of value range
Between, resistance Rc1, the model specification of resistance Rc4, resistance value are identical, between value range 1k Ω -1.2k Ω, more than resistance
Precision is all used to resist the column Chip-R of " Wei Shi companies " that capability of overload is strong in short-term for ± 1%, 50ppm;Capacitance CC7 and
The model specification of capacitance CC9, capacitance are identical, and with temperature drift is small, capacitance with high accuracy, value range 22nF-33nF it
Between, more than capacitance all uses patch capacitor of the precision for ± 5%, NPO materials or more preferable material.
It is the preferred embodiment of the utility model above, the scope of protection of the utility model is not limited, for ability
The deformation and improvement that field technique personnel mentality of designing according to the present utility model is made, should all be considered as the protection of the utility model
Within the scope of.
Claims (10)
1. for the current sampling circuit of three-phase electric energy meter, include the both ends of current sampling signal output, which is characterized in that described
Current sampling signal exports one end and connects resistance Rc1 one end, resistance Rc2 one end respectively, and the current sampling signal output is another
Connection resistance Rc3 one end, resistance Rc4 one end, the resistance Rc2 other ends, the resistance Rc3 other ends are grounded respectively at end.
2. the current sampling circuit according to claim 1 for three-phase electric energy meter, which is characterized in that the resistance Rc2
Thick-film resistor is selected with resistance Rc2.
3. the current sampling circuit according to claim 2 for three-phase electric energy meter, which is characterized in that the thick-film resistor
For ceramic column thick-film resistor.
4. according to any current sampling circuits for three-phase electric energy meter of claim 1-3, which is characterized in that the electricity
The resistance Rc2 other ends, the resistance Rc1 other ends are connect respectively with a capacitance CC7 both ends.
5. the current sampling circuit according to claim 4 for three-phase electric energy meter, which is characterized in that the resistance Rc3
The other end, the resistance Rc4 other ends are connect respectively with a capacitance CC9 both ends.
6. the current sampling circuit according to claim 5 for three-phase electric energy meter, which is characterized in that the capacitance CC7,
Capacitance CC9 uses patch capacitor.
7. the current sampling circuit according to claim 5 for three-phase electric energy meter, which is characterized in that the capacitance CC7,
Capacitance CC9 uses precision as ± 5%, patch capacitor of NPO materials.
8. the current sampling circuit according to claim 5 for three-phase electric energy meter, which is characterized in that the capacitance CC7,
Capacitance CC9 using same size capacitance and/or, the capacitance CC7, capacitance CC9 value range be 22nF-33nF.
9. the current sampling circuit according to claim 1 for three-phase electric energy meter, which is characterized in that the resistance Rc2,
Resistance Rc3 uses the resistance value of same size;And/or between the resistance Rc2,5.1 Ω -7.5 Ω of resistance Rc3 value ranges.
10. the current sampling circuit according to claim 1 for three-phase electric energy meter, which is characterized in that the resistance
Rc1, resistance Rc43 use the resistance value of same size;And/or the resistance Rc1, resistance Rc4 value range 1k Ω -1.2k Ω it
Between.
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Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
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CN108020705A (en) * | 2017-12-27 | 2018-05-11 | 浙江恒业电子有限公司 | Current sampling circuit for three-phase electric energy meter |
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Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
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CN108020705A (en) * | 2017-12-27 | 2018-05-11 | 浙江恒业电子有限公司 | Current sampling circuit for three-phase electric energy meter |
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Address after: No. 1818, Xingping 1st Road, Pinghu Economic Development Zone, Jiaxing City, Zhejiang Province, 314200 Patentee after: Zhejiang Hengye Electronics Co.,Ltd. Address before: No. 1818, Xingping 1st Road, Pinghu Economic Development Zone, Jiaxing City, Zhejiang Province, 314200 Patentee before: ZHEJIANG HENGYE ELECTRONIC Co.,Ltd. |
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