CN115754585A - High-frequency current sensing acquisition unit adopting demagnetization technology - Google Patents
High-frequency current sensing acquisition unit adopting demagnetization technology Download PDFInfo
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- CN115754585A CN115754585A CN202211370302.9A CN202211370302A CN115754585A CN 115754585 A CN115754585 A CN 115754585A CN 202211370302 A CN202211370302 A CN 202211370302A CN 115754585 A CN115754585 A CN 115754585A
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Abstract
The invention discloses a high-frequency current sensing acquisition unit adopting a demagnetization technology, which comprises: a degaussing sensor main body and a data processing part; the degaussing sensor main body comprises a magnetic core, a degaussing winding and a sampling winding; the degaussing winding and the sampling winding are wound on the magnetic core; the data processing part comprises a high-pass filtering loop, a signal conditioning circuit, an analog-to-digital conversion chip, a low-power processor and an optical transceiver module which are sequentially connected; the data processing part also comprises an energy supply module which supplies power to the signal conditioning circuit, the analog-to-digital conversion chip and the low-power consumption processor; the output end of the sampling winding is connected with the input end of the high-pass filtering loop.
Description
Technical Field
The invention belongs to the technical field of high-frequency current sensors, and particularly relates to a high-frequency current sensing and collecting unit adopting a demagnetization technology.
Background
When the facilities such as the transformer, the transmission cable and the like are used for a long time, partial discharge can be caused due to insulation aging, abrasion and the like, the discharge characteristic in the initial stage is usually high-frequency small current, the stage is an important stage for eliminating hidden dangers, and the reliable detection of the small-current discharge signal in the stage has important significance.
The application occasions of the traditional high-frequency current sensor are limited to a certain extent, and the traditional high-frequency current sensor can only be used for a zero sequence line or a transformer grounding line generally. The reason is that the pulse current detected by the high-frequency current transformer is very small and is in mA level, if the high-frequency current sensor is sleeved on the outgoing line side or the transmission line of the transformer, hundreds of thousands of amperes of working current can flow through the transformer, the high-frequency pulse current and the working current can be sampled simultaneously, and the high-frequency pulse current signal is difficult to separate in engineering realization. Secondly, the high-frequency current sensor usually adopts a ferrite core with good high-frequency characteristics, and if the mutual inductor passes hundreds of thousands of working currents, the magnetic core is saturated, so that the mutual inductor cannot work normally. However, discharge usually occurs on the high voltage side, the discharge current may not flow through the zero sequence or ground line, and the discharge current may not be detected by the conventional high frequency current sensor for the zero sequence or ground side.
The Rogowski coil for detecting the current of the power transmission line is generally mainly used for measuring large current, overload current and short-circuit current, can measure high-frequency current under the condition of large power frequency current due to the hollow coil, but has low sensitivity and cannot meet the measurement requirement of milliampere-grade high-frequency current.
A high-frequency current sensor is detected to conventional discharge current for ground connection side can satisfy milliampere level high-frequency current measurement sensitivity requirement, but power frequency operating current can lead to the magnetic core saturation when being used for the high-voltage side, can not normally pass and become under the power frequency heavy current condition.
The high-frequency current sensor adopting the auxiliary winding degaussing technology can realize the detection of a high-frequency discharge signal under low-frequency large current. However, due to factors such as the use environment, the sensor is usually far away from the data acquisition and processing unit, the high-frequency signal sampled by the high-frequency current sensor using the degaussing technique is usually in the order of tens of millivolts, and in the application where the transmission distance is long, the signal is easy to attenuate and is easy to be interfered during signal transmission.
Therefore, a high-frequency current sensor is needed, which can eliminate the influence of power frequency current and detect the high-frequency discharge current of mA level.
Disclosure of Invention
The purpose of the invention is as follows: the invention provides a high-frequency current sensing acquisition unit adopting a demagnetization technology, which is used for fault location, fault diagnosis or relay protection of primary power transmission and transformation equipment such as a power transformer, a high-voltage transmission line and a cable, has the characteristic of effectively transmitting high-frequency small current components under the background of power frequency or low-frequency large current, has a remote transmission function, and simultaneously solves the problems of signal attenuation and easy interference.
The technical scheme is as follows: a high-frequency current sensing acquisition unit adopting a demagnetization technology comprises: a degaussing sensor main body and a data processing part; the degaussing sensor main body comprises a magnetic core, a degaussing winding and a sampling winding; the degaussing winding and the sampling winding are wound on the magnetic core; the data processing part comprises a high-pass filtering loop, a signal conditioning circuit, an analog-to-digital conversion chip, a low-power processor and an optical transceiver module which are sequentially connected; the data processing part also comprises an energy supply module which supplies power to the signal conditioning circuit, the analog-to-digital conversion chip and the low-power consumption processor; and the output end of the sampling winding is connected with the input end of the high-pass filtering loop.
Furthermore, the data processing part also comprises a sampling resistor, the output end of the sampling winding is connected with the sampling resistor, one end of the sampling resistor is grounded, and the other end of the sampling resistor is connected with the input end of the high-pass filtering loop.
Further, the sampling resistor is a non-inductive resistor.
Further, the high-pass filter loop comprises an isolation capacitor and a first resistor; the input end of the isolation capacitor is connected with the output end of the sampling winding, the output end of the isolation capacitor is grounded through the first resistor, and the output end of the isolation capacitor is connected with the input end of the signal conditioning circuit.
Further, the signal conditioning circuit comprises a second resistor, a third resistor, a fourth resistor and an operational amplifier; one end of the second resistor is connected with the output of the high-pass filter loop, the other end of the second resistor is connected with the positive input end of the operational amplifier, the negative input end of the operational amplifier is grounded through a third resistor, the negative input end of the operational amplifier is connected with the output end of the operational amplifier through a fourth resistor, and the output end of the operational amplifier is connected with the input of the analog-to-digital conversion chip.
Furthermore, the signal conditioning circuit comprises a second resistor, a third resistor, a fourth resistor, an operational amplifier and a filter capacitor;
one end of the second resistor is connected with the output of the high-pass filter loop, the other end of the second resistor is connected with the positive input end of the operational amplifier, the negative input end of the operational amplifier is grounded through a third resistor, the negative input end of the operational amplifier is connected with the output end of the operational amplifier through a fourth resistor, the output end of the operational amplifier is grounded through a filter capacitor, and the output end of the operational amplifier is connected with the input of the analog-to-digital conversion chip.
Furthermore, the signal conditioning circuit comprises a second resistor, a third resistor, a fourth resistor, an operational amplifier and a filter capacitor;
one end of the second resistor is connected with the output of the high-pass filter circuit, the other end of the second resistor is connected with the positive input end of the operational amplifier, the negative input end of the operational amplifier is grounded through a third resistor, the negative input end of the operational amplifier is connected with the output end of the operational amplifier through a fourth resistor, and the filter capacitor is connected with the fourth resistor in parallel; the output end of the operational amplifier is connected with the input end of the analog-to-digital conversion chip.
Furthermore, the degaussing sensor main body and the data processing part are both arranged in the same shell.
Further, the energy supply module is a photovoltaic cell module or an AC/DC power supply module.
Further, the isolation capacitor can be replaced by a radio frequency transformer.
Has the advantages that: compared with the prior art, the invention has the following advantages:
(1) The high-frequency current sensing acquisition unit can transmit milliampere high-frequency current signals under the background of hundreds and thousands of amperes of power frequency current, and is specifically embodied as follows: the high-frequency current sensing and collecting unit has an obvious counteraction effect on primary side power frequency current, and can reach 1V/1000A magnitude, namely the induced voltage of 1000A power frequency current is less than 1V; the high-frequency current sensing and collecting unit can detect discharge current signals of hundreds of K to tens of M Hz frequency bands, and the measuring frequency range of the sensor can be adjusted by adjusting the material of the magnetic core; the demagnetization winding of the high-frequency current sensing acquisition unit outputs short circuit or is externally connected with elements such as an inductor, a magnetic bead and the like, the short circuit effect on low-frequency current is obvious, the short circuit effect on the high-frequency current is limited due to the leakage inductance of the demagnetization winding and the impedance of the elements such as the external inductor, the magnetic bead and the like, the sampling coil still has higher high-frequency current sensitivity, the transmission ratio (voltage/current) of the high-frequency current can at least reach 1V/A, namely the induced voltage of a 1mA current signal can reach 1mV;
(2) The high-frequency current sensing acquisition unit adopts the photocell module or the electric energy supply module to supply power, the active circuit is adopted to complete analog-to-digital conversion on site, the converted digital signal is connected with the optical module, and data transmission is carried out through the optical fiber, so that the high-frequency current sensing acquisition unit has strong anti-interference capability, does not attenuate the signal, and can realize long-distance transmission; the high-frequency current sensing acquisition unit can be applied to occasions with serious interference, such as large-scale power transformer bushings and the like, and has particularly obvious effect.
Drawings
FIG. 1 is a block diagram of a system of a high-frequency current sensing and collecting unit using a demagnetization technique;
FIG. 2 is a schematic diagram of a typical implementation circuit of a high-frequency current sensing and collecting unit adopting a demagnetization technique;
fig. 3 is a circuit schematic diagram of another exemplary implementation of a signal conditioning circuit.
Detailed Description
The technical solution of the present invention will be further explained with reference to the accompanying drawings and embodiments.
Example 1:
as shown in fig. 1, the present embodiment provides a high-frequency current sensing and collecting unit adopting a degaussing technique, which mainly includes: a degaussing sensor main body and a data processing part; the degaussing sensor main body comprises a magnetic core, a degaussing winding and a sampling winding; the degaussing winding and the sampling winding are wound on the magnetic core; the data processing part comprises a high-pass filtering loop, a signal conditioning circuit, an analog-to-digital conversion chip, a low-power processor and an optical transceiver module which are sequentially connected; the data processing part also comprises an energy supply module which supplies power to the signal conditioning circuit, the analog-to-digital conversion chip and the low-power-consumption processor; the output end of the sampling winding is connected with the input end of the high-pass filtering loop.
The high-frequency current sensing and collecting unit can be used for fault location, fault diagnosis or relay protection of primary power transmission and transformation equipment such as a power transformer or a high-voltage power transmission line and a cable, and has the characteristic of effectively transmitting high-frequency small current components under the background of power frequency or low-frequency large current and the function of remote transmission.
Example 2:
the embodiment discloses a high-frequency current sensing acquisition unit adopting a demagnetization technology, which mainly comprises a demagnetization sensor main body, a data processing part and a shell; the demagnetization sensor main body comprises a magnetic core, a demagnetization winding N1 and a sampling winding N2; the sampling winding N2 and the degaussing winding N1 of the present embodiment are located at different positions of the magnetic core, and the area occupied by the sampling winding N2 is usually small; the number of turns of the sampling winding N2 and the degaussing winding N1 is determined according to the application. The sampling winding N2 and the degaussing winding N1 are normally wound in a clockwise way and are not overlapped, and in order to reduce parasitic capacitance, the windings can also be wound on the framework and keep a certain distance from the magnetic core. The output of the degaussing winding N1 can be directly short-circuited or be externally connected with elements such as an inductor, a magnetic bead and the like to improve the high-frequency impedance of the degaussing winding. The data processing part comprises a sampling resistor, a high-pass filtering loop, a signal conditioning circuit, an analog-to-digital conversion chip, a low-power-consumption processor, an optical transceiver module and an energy supply module which are sequentially connected; in some embodiments, the energy supply module may be a photovoltaic module or an AC/DC power module.
Fig. 1 shows an architecture diagram of the high-frequency current sensing and collecting unit according to this embodiment, in which a degaussing sensor main body 1, a high-pass filter loop 2, a signal conditioning circuit 3, an analog-to-digital conversion chip 4, a low-power processor 5, and an optical transceiver module 6 are connected in sequence, and an energy supply module is used to provide a power VCC for the signal conditioning circuit 3, the analog-to-digital conversion chip 4, and the low-power processor 5. The sampling winding N2, the degaussing winding N1 and the data processing part are all arranged in the same shell, and the shell can be made of metal (with an opening at the inner layer) or nonmetal. In the embodiment, the data processing part is arranged in the metal shell, so that analog-to-digital conversion is carried out on the sampled data nearby, and the data after the analog-to-digital conversion is transmitted through the optical fiber, so that signal attenuation and interference can be avoided to the maximum extent. According to application occasions, the magnetic core of the embodiment can be a whole ring, can be two semi-rings, can also be a magnetic core in other shapes or formed by splicing a plurality of semi-rings, and the size of the magnetic core is determined according to the application occasions. The core of the present embodiment is usually a core having excellent high-frequency characteristics, for example, ferrite having excellent high-frequency characteristics, and a core made of other material may be used. The sampling resistor of the present embodiment is usually a non-inductive resistor. The output of the sampling winding N2 of the embodiment is normally connected with a non-inductive resistor or directly sent to a high-pass filter circuit without being connected with a resistor. The degaussing winding N1 of this embodiment may be an enameled wire or an insulated wire, and the cross-sectional area of the wire is determined according to the primary side working current and the number of turns, or may be replaced by another type of wire. The high-frequency current sensing acquisition unit of the embodiment only has one sampling winding and one degaussing winding, but the sampling winding and the degaussing winding can be added according to application occasions.
Fig. 2 shows a circuit diagram of an exemplary implementation of the high-frequency current sensing acquisition unit of the present embodiment; as shown in fig. 2, the high-pass filter loop 2 is composed of an isolation capacitor C1 and a first resistor R2; the signal conditioning circuit 3 consists of a second resistor R3, a third resistor R4, a fourth resistor R5 and an operational amplifier U1; the analog-to-digital conversion chip 4 is composed of an ADC chip U2; the low-power processor 5 is composed of an FPGA U3; the optical transceiver module 6 is constituted by the OPT U4. The output of the sampling winding N2 is connected with a sampling resistor R1; one end of the sampling resistor R1 is grounded, the other end of the sampling resistor R1 is connected with the input end of the isolation capacitor C1, the output end of the isolation capacitor C1 is grounded through the first resistor R2, the output end of the isolation capacitor C1 is connected with one end of the second resistor R3, the other end of the second resistor R3 is connected with the positive input end of the operational amplifier U1, the negative input end of the operational amplifier U1 is grounded through the third resistor R4, the negative input end of the operational amplifier U1 is connected with the output end of the operational amplifier U1 through the fourth resistor R5, the output end of the operational amplifier U1 is connected with the input end of the ADC chip U2, the output end of the ADC chip U2 is connected with the input end of the FPGA U3, the output end of the FPGA U3 is connected with the input end of the OPT U4, and the photocell module or the AC/DC power module outputs the working power supply to the U1, U2 and the U3 provides a working power supply.
In the high-pass filtering loop 2 of the present embodiment, in addition to isolation by the isolation capacitor C1 in the typical implementation circuit, a radio frequency transformer may also be used to implement high-pass filtering. For the signal conditioning circuit 3 of this embodiment, a filter capacitor Cn may also be added to the input end and the output end of the operational amplifier U1, and the filter capacitor Cn may also be connected in parallel with the third resistor R4 and the fourth resistor R5 to improve the transmission effect, as shown in fig. 3, the main function of signal conditioning is to amplify the sampling signal. The low power processor 5 of the present embodiment may be implemented by other types of processors besides an FPGA in a typical implementation circuit.
The demagnetization effect and the sampling effect of the high-frequency current sensing and collecting unit of the embodiment are further described through experiments. The degaussing sensor body for testing consists of a magnetic core with the size of 120/85/20 (mm), a 3-turn sampling winding and a 45-turn degaussing winding, and a 100-ohm noninductive resistor is adopted as a sampling resistor.
Table 1 shows the primary side power frequency current demagnetization effect, and table 2 shows the voltage current transmission relationship at high frequency; tests show that the transmission ratio of the power frequency current is less than 0.3V/1000A, the transmission ratio of the high-frequency signal above 200kHz is greater than 1V/1A, the high-frequency transmission ratio of the embodiment is greater than that of the existing high-frequency current sensor, and the high-frequency transmission ratios of different frequency bands are more stable.
TABLE 1 Primary side Power frequency Current demagnetization Effect
TABLE 2 Voltage-Current Transmission relationship at high frequencies
As can be seen from the tables 1 and 2, the sensing acquisition unit is placed in the sensor shell adopting the demagnetization technology, so that the attenuation on the transmission line can be well eliminated, and the anti-interference capability is strong.
All possible combinations of the technical features in the above embodiments may not be described for the sake of brevity, but should be considered as being within the scope of the present disclosure as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, and these are all within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. The utility model provides an adopt high frequency current sensing acquisition unit of demagnetization technique which characterized in that: the method comprises the following steps: a degaussing sensor main body and a data processing part;
the degaussing sensor main body comprises a magnetic core, a degaussing winding and a sampling winding; the degaussing winding and the sampling winding are wound on the magnetic core;
the data processing part comprises a high-pass filtering loop, a signal conditioning circuit, an analog-to-digital conversion chip, a low-power processor and an optical transceiver module which are sequentially connected; the data processing part also comprises an energy supply module which supplies power to the signal conditioning circuit, the analog-to-digital conversion chip and the low-power consumption processor;
and the output end of the sampling winding is connected with the input end of the high-pass filtering loop.
2. The high-frequency current sensing acquisition unit adopting a demagnetization technology according to claim 1, characterized in that: the data processing part also comprises a sampling resistor, the output end of the sampling winding is connected with the sampling resistor, one end of the sampling resistor is grounded, and the other end of the sampling resistor is connected with the input end of the high-pass filtering loop.
3. The high-frequency current sensing acquisition unit adopting a demagnetization technology according to claim 2, characterized in that: the sampling resistor is a non-inductive resistor.
4. The high-frequency current sensing acquisition unit adopting a demagnetization technology according to claim 1, characterized in that: the high-pass filtering loop comprises an isolation capacitor and a first resistor; the input end of the isolation capacitor is connected with the output end of the sampling winding, the output end of the isolation capacitor is grounded through the first resistor, and the output end of the isolation capacitor is connected with the input end of the signal conditioning circuit.
5. The high-frequency current sensing acquisition unit adopting a demagnetization technology according to claim 1, characterized in that: the signal conditioning circuit comprises a second resistor, a third resistor, a fourth resistor and an operational amplifier;
one end of the second resistor is connected with the output of the high-pass filter loop, the other end of the second resistor is connected with the positive input end of the operational amplifier, the negative input end of the operational amplifier is grounded through a third resistor, the negative input end of the operational amplifier is connected with the output end of the operational amplifier through a fourth resistor, and the output end of the operational amplifier is connected with the input of the analog-to-digital conversion chip.
6. The high-frequency current sensing acquisition unit adopting the demagnetization technology according to claim 1, characterized in that: the signal conditioning circuit comprises a second resistor, a third resistor, a fourth resistor, an operational amplifier and a filter capacitor;
one end of the second resistor is connected with the output of the high-pass filter loop, the other end of the second resistor is connected with the positive input end of the operational amplifier, the negative input end of the operational amplifier is grounded through a third resistor, the negative input end of the operational amplifier is connected with the output end of the operational amplifier through a fourth resistor, the output end of the operational amplifier is grounded through a filter capacitor, and the output end of the operational amplifier is connected with the input of the analog-to-digital conversion chip.
7. The high-frequency current sensing acquisition unit adopting the demagnetization technology according to claim 1, characterized in that: the signal conditioning circuit comprises a second resistor, a third resistor, a fourth resistor, an operational amplifier and a filter capacitor;
one end of the second resistor is connected with the output of the high-pass filter circuit, the other end of the second resistor is connected with the positive input end of the operational amplifier, the negative input end of the operational amplifier is grounded through a third resistor, the negative input end of the operational amplifier is connected with the output end of the operational amplifier through a fourth resistor, and the filter capacitor is connected with the fourth resistor in parallel; the output end of the operational amplifier is connected with the input end of the analog-to-digital conversion chip.
8. The high-frequency current sensing acquisition unit adopting the demagnetization technology according to claim 1, characterized in that: the degaussing sensor main body and the data processing part are both arranged in the same shell.
9. The high-frequency current sensing acquisition unit adopting the demagnetization technology according to claim 1, characterized in that: the energy supply module is a photovoltaic cell module or an AC/DC power supply module.
10. The high-frequency current sensing acquisition unit adopting the demagnetization technology according to claim 4, characterized in that: the isolation capacitor can be replaced by a radio frequency transformer.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116666036A (en) * | 2023-05-17 | 2023-08-29 | 珠海多创科技有限公司 | Demagnetizing module and current sensor |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116666036A (en) * | 2023-05-17 | 2023-08-29 | 珠海多创科技有限公司 | Demagnetizing module and current sensor |
| CN116666036B (en) * | 2023-05-17 | 2024-02-13 | 珠海多创科技有限公司 | Demagnetizing module and current sensor |
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