CN212540639U

CN212540639U - Current sensor based on Rogowski coil and suitable for measurement and protection of circuit breaker

Info

Publication number: CN212540639U
Application number: CN202021226099.4U
Authority: CN
Inventors: 胡长鹏; 贾建春; 金小伍
Original assignee: Luoyi Technology Shanghai Co ltd
Current assignee: Luoyi Technology Shanghai Co ltd
Priority date: 2020-06-29
Filing date: 2020-06-29
Publication date: 2021-02-12
Anticipated expiration: 2030-06-29

Abstract

The utility model discloses a current sensor based on roche coil is applicable to the measurement and protection of circuit breaker, including roche coil module, integrator module, blocking amplification module and voltage lifting module, the current of real time monitoring circuit breaker measuring line provides two way current output, gives the electric energy chip measurement output all the way, obtains accurate current value; and the other path is sent to a single chip microcomputer for protection output, protection and wave recording are implemented, and the fault current waveform is observed. The utility model has the advantages that can improve current measurement accuracy greatly, also improve the precision of protection current simultaneously.

Description

Current sensor based on Rogowski coil and suitable for measurement and protection of circuit breaker

Technical Field

The utility model relates to a current sensor, in particular to current sensor based on roche coil is applicable to the measurement and the protection of circuit breaker.

Background

The circuit breaker has multiple protection functions, such as overload, short circuit and under-voltage protection, and also has the advantages of adjustable action value, high breaking capacity, convenient operation and safety, and is widely applied. The electronic circuit breaker has more complete functions and more accurate action, and is very easy to realize distributed current control. The current needs to be monitored in many occasions to obtain real-time current value and obtain more analysis data, the maximum current to be monitored is more than 10 times of rated current, the volume of the current sensor is very large, and the cost and the system integration difficulty are increased. If monitoring and protection can be achieved in the circuit breaker, the economic benefits brought are obvious.

The Rogowski coil is characterized in that a wire is uniformly wound on a non-ferromagnetic structure with uniform size, electromotive force is induced through a winding coil, an output signal of the Rogowski coil is a differential voltage signal of a current to be measured, the differential voltage signal can be restored into a signal to be measured through an integrator, the Rogowski coil has the advantages of small size and difficulty in saturation, and the measurement of an ultra-large current value can be realized under the condition that a very small space is occupied.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the technical problem that a measurement accuracy is high is applicable to the current sensor of measurement and protection of circuit breaker based on the rogowski coil will be provided.

In order to solve the technical problem, the utility model provides a current sensor based on roche coil is applicable to measurement and protection of circuit breaker, include

The Rogowski coil module: the output signal is a differential voltage signal of the measured current;

an integrator module: converting the differential voltage signal into a voltage signal of the measured current;

a blocking amplification module: filtering the voltage signal of the integrator module to remove direct current, and amplifying;

a voltage boost module: after the negative voltage signal is lifted, the negative voltage signal enters a single chip microcomputer ADC for collection;

monitoring the current of a circuit breaker measuring line in real time, providing two paths of current outputs, and sending one path of current to an electric energy chip for measuring and outputting to obtain an accurate current value; and the other path is sent to a single chip microcomputer for protection output, protection and wave recording are implemented, and the fault current waveform is observed.

And two groups of blocking amplification modules are arranged and respectively correspond to the measurement output and the protection output. The blocking amplifying module is provided with a blocking circuit consisting of capacitance resistors, a signal output by the integrator module passes through the blocking circuit to the in-phase end of the in-phase amplifier to form a following amplifier, and an output signal is adjusted by the adjustable resistor to calibrate output precision.

The voltage lifting module is applied to the tail end of the protection output and is a differential amplification circuit.

The integrator modules are provided with two groups, the two groups correspond to measurement output and protection output respectively, different output variable ratio values are obtained by applying different integration time coefficients, and the different output variable ratio values enter an electric energy chip and a single chip microcomputer to be collected respectively.

The integrator module is arranged between the Rogowski coil and the blocking and amplifying module, one end of each of two output ends of the Rogowski coil is grounded, the other end of each output end of the Rogowski coil is connected with the inverting input end of the operational amplifier of the integrator module through an integrating resistor, the integrating capacitor is connected with the inverting input end and the output end of the operational amplifier, and the integrating resistors and the integrating capacitor form an integration time coefficient to obtain different output variable ratios.

The Rogowski coil module is a precise Rogowski coil, the position error of the Rogowski coil module is less than 1%, and large errors caused by different conductor positions are prevented.

The utility model has the advantages that:

1) the utility model discloses implant measuring circuit in the circuit breaker, will need the function that traditional current sensor accomplished originally to integrate into the circuit breaker, cooperate the electric energy chip, obtain parameters such as electric energy, power factor, improved the integrated level, richened the function of circuit breaker;

2) the utility model discloses correspond a set of luo shi coil module with two sets of integrator modules, it is the innovation of the utility model, because contained an air core coil in the original circuit breaker, only carry out simple amplification comparison, only be used for the protection, the precision is very poor, after having introduced integrator module and electric energy chip, can improve the current measurement precision greatly, has also improved the precision of protection current simultaneously;

3) the utility model discloses have the oscillography function, provide detailed waveform reference when taking place unusually, further expanded the function of circuit breaker, provide the condition for careful control line current.

Drawings

The accompanying drawings, which form a part of the present application, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:

fig. 1 is a schematic circuit block diagram of the present invention;

FIG. 2 is a circuit diagram of the present invention;

description of the figures

P1 — integrator module 1; p2-dc blocking amplification module 1;

p3 — integrator module 2; p4-dc blocking amplification module 2;

p5 — voltage raising module.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Fig. 1 shows a schematic block circuit diagram of an embodiment of the present invention, and fig. 2 shows a circuit diagram of an embodiment of the present invention. As shown in fig. 1 and 2, the utility model provides a current sensor based on the measurement and protection that rogowski coil is applicable to the circuit breaker, a set of rogowski coil module output connects two sets of integrator modules, and the output signal of rogowski coil module is the differential voltage signal of the measured current, and the integrator module converts the differential voltage signal into the voltage signal of the measured current, sends to blocking the direct current of the module filtering of amplification, enlargies again; as shown in fig. 2, the upper and lower outputs correspond to the measurement output and the protection output, respectively, and the upper output is sent to the electric energy chip for measurement output to obtain accurate parameters of electric energy, power factor and the like; the lower circuit protection output is lifted by 1.25V through the voltage lifting module P5, and then directly enters the single chip microcomputer ADC for collection, protection and wave recording are implemented, detailed waveform reference is provided when abnormality occurs, and the waveform of fault current is observed.

The utility model discloses a rogowski coil module, integrator module P1 and P3, block DC and enlarge module P2 and P4, and voltage lifting module P5.

The integrator modules P1 and P3 convert the differential voltage signal used by the rogowski coil module into a voltage signal reflecting the primary current, and are disposed between the rogowski coil module and the dc blocking amplification module. As shown in fig. 2, one end of each of two output terminals of the rogowski coil module is grounded, the other end of each of the two output terminals is connected to the inverting input terminals of the operational amplifiers U1A and U3A through integrating resistors R1 and R6, C1 and C3 are integrating capacitors, and are connected to the inverting input terminals and the output terminals of the operational amplifiers, respectively, the integrating resistors and the integrating capacitors jointly determine the integration time of each group, so as to obtain different transformation ratio coefficients, and R2 and R7 are dc gain limiting resistors, so as to limit the dc gain caused by the offset voltage of the operational amplifiers.

The DC blocking amplification modules P2 and P4 are used for filtering a voltage signal obtained by the integrator module to remove direct current, amplifying the voltage signal, and calibrating the output precision by adjusting the adjustable resistor; which is located after the integrator module. The output signal of the integrator module passes through a DC blocking circuit formed by a capacitor and a resistor and reaches the in-phase end of the in-phase amplifier to form a following amplifier. The dc blocking process is required because the output signal of the integrating circuit in the previous stage is not located at the center point due to the dc gain caused by the offset voltage of the integrating circuit in the previous stage. The output signal is adjusted through adjustable resistors RX1 and RX2, and the output accuracy is calibrated. Wherein: the C2 and the R3 form a measurement output channel blocking, the C4 and the R9 form a protection channel blocking, and the RX1 and the RX2 are respectively responsible for the amplification factor adjustment of two-path output.

The voltage raising module P5 is located at the end of the protection output, and R10, R11, R12 and R13 form a differential amplifier circuit, wherein R10= R12 and R11= R13.

The operational amplifier shown in fig. 2 is supplied with plus and minus 5V voltage.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A current sensor based on Rogowski coil is applicable to measurement and protection of circuit breaker, its characterized in that: comprises that

the circuit breaker is monitored in real time to measure the current of a line, two paths of current outputs are provided, one path of current is sent to an electric energy chip to be measured and output, and the other path of current is sent to a single chip microcomputer to be protected and output.

2. The current sensor based on rogowski coils suitable for measurement and protection of circuit breakers according to claim 1, wherein: and two groups of blocking amplification modules are arranged and respectively correspond to the measurement output and the protection output.

3. The current sensor suitable for measurement and protection of circuit breakers based on rogowski coils, as claimed in claim 2, wherein: the blocking amplifying module is provided with a blocking circuit consisting of capacitance resistors, a signal output by the integrator module passes through the blocking circuit to the in-phase end of the in-phase amplifier to form a following amplifier, and an output signal is adjusted by the adjustable resistor to calibrate output precision.

4. The current sensor based on rogowski coils suitable for measurement and protection of circuit breakers according to claim 1, wherein: the voltage lifting module is applied to the tail end of the protection output and is a differential amplification circuit.

5. The current sensor based on rogowski coils suitable for measurement and protection of circuit breakers according to claim 1, wherein: the integrator modules are provided with two groups, the two groups correspond to measurement output and protection output respectively, different output variable ratio values are obtained by applying different integration time coefficients, and the different output variable ratio values enter an electric energy chip and a single chip microcomputer to be collected respectively.

6. The current sensor suitable for measurement and protection of circuit breakers based on rogowski coils, as claimed in claim 5, wherein: the integrator module is arranged between the Rogowski coil and the blocking and amplifying module, one end of each of two output ends of the Rogowski coil is grounded, the other end of each output end of the Rogowski coil is connected with the inverting input end of the operational amplifier of the integrator module through an integrating resistor, the integrating capacitor is connected with the inverting input end and the output end of the operational amplifier, and the integrating resistors and the integrating capacitor form an integration time coefficient to obtain different output variable ratios.

7. The current sensor based on rogowski coils suitable for measurement and protection of circuit breakers according to claim 1, wherein: the Rogowski coil module is a precise Rogowski coil, and the position error of the Rogowski coil module is less than 1%.