CN213069056U - Power system and load detection circuit thereof - Google Patents
Power system and load detection circuit thereof Download PDFInfo
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- CN213069056U CN213069056U CN202021511686.8U CN202021511686U CN213069056U CN 213069056 U CN213069056 U CN 213069056U CN 202021511686 U CN202021511686 U CN 202021511686U CN 213069056 U CN213069056 U CN 213069056U
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Abstract
The utility model provides an electric power system and load detection circuit thereof, load detection circuit includes: a first current transformer; a second current transformer; the second sampling processing circuit is connected with the second current transformer, sequentially performs high-pass filtering, amplification and analog-to-digital conversion on the second working characteristic and outputs a second sampling processing signal; a control circuit storing an authorized load working threshold, said control circuit receiving a first working sampling processing signal output by said first sampling processing circuit and a second sampling processing signal output by said second sampling processing circuit, respectively; and the actuator is connected to the control circuit, wherein the control circuit compares the first sampling processing signal and the second sampling processing signal with the authorized load operating characteristic parameter respectively. The utility model discloses whether can the accurate load of judging in the circuit be the mandate load to circuit security and stability have been improved.
Description
Technical Field
The utility model relates to an electric power system field especially relates to electric power system and load detection circuit thereof.
Background
Low voltage power distribution systems in the power domain have a number of protective functions, such as monitoring for instantaneous high currents to prevent short circuits, detecting for long delay overcurrents to avoid overloads, sampling for residual currents to avoid human electrocution, and arc fault detection functions for detecting arc faults. Most of these protection functions are possible failures of the low-voltage system and keep operators and installations out of danger.
An illegal appliance, in particular an electromagnetic emission exceeding a threshold value, is often caused by a fault in the EMC related function of the product or a fault in the quality of the product being low. These types of products may cause other normal equipment to malfunction or cause other protective functions to fail, such as an arc fault.
The prior art has no technical scheme which can solve the problems.
SUMMERY OF THE UTILITY MODEL
The utility model discloses a first aspect provides a load detection circuit of electric power system, a serial communication port, load detection circuit includes: the first current transformer is connected to a zero line of a line and samples a first working characteristic when the load is powered on the basis of a first frequency; a second current transformer connected to a zero line of the line and sampling a second operating characteristic of the load when the load is powered based on a second frequency, wherein the second frequency is higher than the first frequency; the first sampling processing circuit is connected with the first current transformer, sequentially performs low-pass filtering, amplification and analog-to-digital conversion processing on the first working characteristic and outputs a first sampling processing signal; the second sampling processing circuit is connected with the second current transformer, sequentially performs high-pass filtering, amplification and analog-to-digital conversion on the second working characteristic and outputs a second sampling processing signal; a control circuit storing an authorized load working threshold, said control circuit receiving a first working sampling processing signal output by said first sampling processing circuit and a second sampling processing signal output by said second sampling processing circuit, respectively; and the control circuit compares the first working sampling processing signal and the second sampling processing signal with authorized load working characteristic parameters respectively, and controls the first actuator to execute disconnection operation of a load on a line and reporting operation to an upper-level system when the first working sampling processing signal and the second sampling processing signal do not accord with the authorized load working characteristic parameters.
Further, the first operating characteristic is a first current, and the second operating characteristic is a second current, wherein a frequency of the second current is higher than a frequency of the first current.
Further, the first sampling processing circuit includes a low-pass filter, an operational amplifier and an analog-to-digital converter, which are connected in series in sequence, wherein the low-pass filter performs low-pass filtering on the first current, the operational amplifier amplifies the first current after the low-pass filtering, and the analog-to-digital converter converts the amplified current signal from an analog signal to a digital signal.
Further, the second sampling processing circuit includes a high-pass filter, a logarithmic amplifier, an operational amplifier, and a comparator, which are connected in series in this order, wherein the high-pass filter performs high-pass filtering on the second current, the logarithmic amplifier amplifies the high-pass filtered second current, the operational amplifier adjusts the power amplitude of the second current, and the comparator performs analog-to-digital conversion on the second current based on a threshold.
Further, the actuator includes: a trip which drives a switch in the line to perform a disconnection operation of a load on the line; and the LED display lamp prompts whether the line has irregular load or not based on different colors and executes the report operation of the superior system.
Further, the actuator comprises an LED display screen.
Further, the value range of the second frequency is 500KHz to 30MHz, and the value range of the second frequency is less than 500 KHz.
Further, the control circuit comprises an MCU or a CPU.
Further, the load detection circuit is suitable for a low-voltage line.
The utility model discloses the second aspect provides an electric power system, a serial communication port, electric power system includes the utility model discloses the first aspect electric power system's load detection circuit.
The utility model provides an electric power system and load detection circuit thereof, whether it can be to the load of the low voltage circuit connection that has protect function to authorize the load and judge and carry out relevant operation to ensure the security and the stability of circuit. The utility model provides an electric power system and load detection circuit thereof can increase irregular load detection function for traditional protection circuit, also can be for extra irregular load detection function of low pressure protection product extension.
Drawings
FIG. 1 is a circuit connection diagram of a power system;
fig. 2 is a circuit diagram of a load detection circuit of a low voltage protection circuit according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of the high frequency sampling circuit and the low frequency sampling circuit of the circuit connection diagram of the load detection circuit of the low voltage protection circuit according to an embodiment of the present invention.
Detailed Description
The following describes embodiments of the present invention with reference to the drawings.
The utility model provides an electric power system and load detection circuit thereof, whether it can be to the load of the low voltage circuit connection that has protect function to authorize the load and judge and carry out relevant operation to ensure the security and the stability of circuit.
The utility model discloses the first aspect provides electric power system's load detection circuit.
Figure 1 is a circuit connection diagram of a power system,which is in particular a direct current power system. Wherein, the AC power supply S2Is two power supply branches B connected in parallel1And B2Power supply, the power branch B1And B2Each having an alternating current to direct current converter (AC/DC converter). Detailed power branch B1And B2And also respectively connected in series with a protection circuit PD1And PD2Wherein in the protection circuit PD1And PD2A first parallel branch, a second parallel branch, a third parallel branch and a fourth parallel branch are arranged below the filter. Wherein the first parallel branch has a protection circuit PD11The second parallel path has a protection circuit PD12The third parallel branch has a protection circuit PD21The fourth parallel path has a protection circuit PD22. The DC power system also comprises a battery source B3And a photovoltaic power supply B4Wherein the battery source B3And a photovoltaic power supply B4And are respectively connected in series with a protection circuit PD3And PD4. In the protection circuit PD3And PD4And a fifth parallel branch, a sixth parallel branch and a seventh parallel branch are arranged below the filter. Wherein, the fifth parallel branch is connected in series with a protection circuit PD31The sixth parallel branch is connected in series with a protection circuit PD32The seventh parallel branch is connected in series with a protection circuit PD41. Wherein the protection circuit PD11、PD12、PD21、PD22、PD31、 PD32、PD41Hereinafter, at least one load is connected in series or a plurality of loads are connected in parallel, respectively.
Optionally, the utility model provides a load detection circuit 100 connect in the protection circuit of electric power system. Optionally, the load detection circuit 100 is connected between a protection circuit of the power system and a plurality of parallel loads.
For example, as shown in fig. 1, the load detection circuit 100 provided by the present invention may be embedded in or coupled to the protection circuit PD1、PD2、PD3、PD4、PD11、PD12、PD21、PD22、 PD31、PD32、PD41Any one of them. Alternatively, the utility model provides a load detection circuit 100 can connect in protection circuit PD11、PD12、PD21、PD22、PD31、PD32、PD41Downstream of (c).
Fig. 2 is a circuit diagram of a load detection circuit of a low voltage protection circuit according to an embodiment of the present invention. As shown in fig. 2, the load detection circuit 100 includes a first current transformer CT1And a second current transformer CT2A second sampling processing circuit 110, a first sampling processing circuit 120, a control circuit 130 and an actuator 140. N is the zero line and L is the live line.
Specifically, a first current transformer CT1The circuit is connected to a zero line N of the line and samples a first operating characteristic of the load when the load is powered on the basis of a first frequency. Second current transformer CT2And the second working characteristic is sampled based on a second frequency when the load is powered, wherein the second frequency is higher than the first frequency. Wherein the first current transformer CT1Is a low-voltage current transformer, a second current transformer CT2Is a high-voltage current transformer. Wherein, the first current transformer CT1And a second current transformer CT2Acting as a circuit converter. First current transformer CT1The low-voltage sampling circuit belongs to low voltage, samples low-frequency current and is used for instantaneous overcurrent protection, long-delay overcurrent protection and the like. Second current transformer CT2Is responsible for detecting and sampling high frequency current and for detecting electromagnetic emission non-uniform loads (electromagnetic emission) loads.
Wherein the first sampling processing circuit 120 is connected to the first current transformer CT1And sequentially performing low-pass filtering, amplification and analog-to-digital conversion processing on the first working characteristic, and outputting a first sampling processing signal. The second sampling processing circuit 110 is connected to the second current transformer CT2And sequentially performing high-pass filtering, amplification and analog-to-digital conversion processing on the second working characteristic, and outputting a second sampling processing signal.The first sample processing circuit 120 also performs protection functions such as instantaneous overcurrent protection and long-delay overcurrent protection.
The control circuit 130 stores an authorized load working threshold, and the control circuit 130 receives the first working sampling processing signal output by the first sampling processing circuit 120 and the second sampling processing signal output by the second sampling processing circuit 110, respectively. The actuator 140 is connected to the control circuit 130, wherein the control circuit 130 compares the first sampling processing signal and the second sampling processing signal with an authorized load operating characteristic parameter, and when the first sampling processing signal and the second sampling processing signal do not conform to the authorized load operating characteristic parameter, the control circuit controls the first actuator 140 to perform an operation of disconnecting a load on a line and an operation of reporting to an upper-level system. For example, the authorized load operating characteristic parameter may be a current/voltage range, and once the first sampled and processed signal and the second sampled and processed signal exceed a first range, it is determined that the first sampled and processed signal and the second sampled and processed signal do not conform to the authorized load operating characteristic parameter.
Further, the first operating characteristic is a first current, and the second operating characteristic is a second current, wherein a frequency of the second current is higher than a frequency of the first current.
Fig. 3 is a schematic structural diagram of the high frequency sampling circuit and the low frequency sampling circuit of the circuit connection diagram of the load detection circuit of the low voltage protection circuit according to an embodiment of the present invention. As shown in fig. 3, the first sampling processing circuit 120 includes a low-pass filter 121, a first operational amplifier 122 and an analog-to-digital converter 123, which are connected in series in sequence, wherein the low-pass filter 121 performs low-pass filtering on the first current, the first operational amplifier 122 amplifies the first current after the low-pass filtering, and the analog-to-digital converter 123 converts the amplified current signal from an analog signal to a digital signal. The second sampling processing circuit 110 includes a high-pass filter 111, a logarithmic amplifier 112, a second operational amplifier 113, and a comparator 114, which are connected in series in sequence, wherein the high-pass filter 111 performs high-pass filtering on the second current, the logarithmic amplifier 112 amplifies the high-pass filtered second current, the second operational amplifier 113 adjusts the power amplitude of the second current, and the comparator 114 performs analog-to-digital conversion on the second current based on a threshold. The low frequency first sampling processing circuit 120 obtains a detailed current curve of the load operation, and the high frequency second sampling processing circuit 110 compares the currents based on a current threshold to complete the analog-digital conversion of the signal.
Specifically, the second sampling processing circuit 110 is responsible for EMC irregularity detection. As shown in fig. 3, the second sample processing circuit 110 includes a high-pass filter 111, a logarithmic amplifier 112, a second operational amplifier 113, and a comparator 114. The second sample processing circuit 110 is used to suppress low frequency signals, particularly power frequencies around 50/60Hz, and the high pass filter 111 is typically around 100 KHz. The second operational amplifier 113 is used to detect the high frequency and the second operational amplifier 113 is used to adjust the high frequency power amplitude. The comparator 114 is responsible for comparing the high frequency signal with a threshold, which can be implemented by an analog comparator or a digital comparator. When comparator 114 is a digital comparator, the signal needs to be digitized with an analog-to-digital converter and then compared at control circuit 130. The logarithmic amplifier 112 amplifies signals with particularly weak data, has a wide frequency band and a high amplification factor, and meets the requirement of dynamic amplification. The second operational amplifier 113 further amplifies the signal within a certain range and then fine-tunes the signal using a logarithmic amplifier. The comparator 114 is responsible for comparing the high frequency signal with a threshold, which can be implemented by an analog comparator or a digital comparator. When comparator 114 is a digital comparator, the signal needs to be digitized with an analog-to-digital converter and then compared at control circuit 130. For example, a threshold 2A is set, and when the current range is from 0.1A to 3A, greater than 2A is converted into a digital signal 1, and less than 2A is converted into a digital signal 0.
Further, the actuator 140 includes a release and an LED display. Wherein the trip drives a switch in the line to perform a disconnection operation of the load on the line. The LED display lamp prompts whether the line has irregular load or not based on different colors, and executes the report operation of the superior system. Optionally, the actuator 140 may further include an LED display screen. Specifically, the actuator 140 is responsible for performing reporting, disconnection, and alarm operations. For example, when there is an irregular load in the power system, the actuator 140 reports this to the customer. Actuator 140 may optionally include an LED display or LED screen, for example, a red LED display may indicate an irregular load in the line. Configuration circuitry in the actuator 140 is used to configure the actuator to perform an action, such as triggering a switch or reporting a result, when an irregular load is detected in the line.
Further, the value range of the second frequency is 500KHz to 30MHz, and the value range of the second frequency is less than 500 KHz.
Further, the control circuit 130 includes an MCU or a CPU.
In particular, the load detection circuit 100 is suitable for low voltage lines.
The utility model discloses the second aspect provides an electric power system, electric power system includes the utility model discloses the first aspect electric power system's load detection circuit 100.
The utility model provides an electric power system and load detection circuit thereof, whether it can be to the load of the low voltage circuit connection that has protect function to authorize the load and judge and carry out relevant operation to ensure the security and the stability of circuit. The utility model provides an electric power system and load detection circuit thereof can increase irregular load detection function for traditional protection circuit, also can be for extra irregular load detection function of low pressure protection product extension.
While the present invention has been described in detail with reference to the preferred embodiments thereof, it should be understood that the above description should not be taken as limiting the present invention. Numerous modifications and alterations to the present invention will become apparent to those skilled in the art upon reading the foregoing description. Accordingly, the scope of the invention should be limited only by the attached claims. Furthermore, any reference signs in the claims shall not be construed as limiting the claim concerned; the word "comprising" does not exclude the presence of other devices or steps than those listed in a claim or the specification; the terms "first," "second," and the like are used merely to denote names, and do not denote any particular order.
Claims (10)
1. A load detection circuit for an electrical power system, the load detection circuit comprising:
a first Current Transformer (CT)1) Connected to the neutral line (N) of the line, which samples a first operating characteristic of the load when it is powered on, on the basis of a first frequency;
a second Current Transformer (CT)2) -connected to the neutral line (N) of the line, which samples a second operating characteristic of the load when it is powered on, based on a second frequency, wherein the second frequency is higher than the first frequency;
a first sampling processing circuit (120) connected to said first Current Transformer (CT)1) Low-pass filtering, amplifying and analog-to-digital conversion processing are sequentially performed on the first working characteristic, and a first sampling processing signal is output;
a second sampling processing circuit (110) connected to said second Current Transformer (CT)2) High-pass filtering, amplifying and analog-to-digital conversion processing are sequentially performed on the second working characteristic, and a second sampling processing signal is output;
a control circuit (130) storing an authorized load operation threshold, said control circuit (130) receiving a first operational sample processing signal output by said first sample processing circuit (120) and a second sample processing signal output by said second sample processing circuit (110), respectively;
an actuator (140) connected to the control circuit (130),
the control circuit (130) compares the first working sampling processing signal and the second sampling processing signal with an authorized load working characteristic parameter respectively, and when the first working sampling processing signal and the second sampling processing signal do not accord with the authorized load working characteristic parameter, the control circuit controls the first actuator (140) to execute disconnection operation of a load on a line and report operation to an upper-level system.
2. The load detection circuit of claim 1, wherein the first operating characteristic is a first current and the second operating characteristic is a second current, wherein a frequency of the second current is higher than a frequency of the first current.
3. The load detection circuit of the power system according to claim 2, wherein the first sampling processing circuit (120) comprises a low pass filter (121), a first operational amplifier (122) and an analog-to-digital converter (123) connected in series in sequence, wherein the low pass filter (121) performs low pass filtering on the first current, the first operational amplifier (122) amplifies the first current after the low pass filtering, and the analog-to-digital converter (123) converts the amplified current signal from an analog signal to a digital signal.
4. The load detection circuit of the power system according to claim 2, wherein the second sampling processing circuit (110) comprises a high-pass filter (111), a logarithmic amplifier (112), a second operational amplifier (113) and a comparator (114) connected in series in this order, wherein the high-pass filter (111) performs high-pass filtering on the second current, the logarithmic amplifier (112) amplifies the high-pass filtered second current, the second operational amplifier (113) adjusts the power amplitude of the second current, and the comparator (114) performs analog-to-digital conversion on the second current based on a threshold.
5. The load detection circuit of an electric power system according to claim 2, wherein the actuator (140) comprises:
a trip which drives a switch in the line to perform a disconnection operation of a load on the line;
and the LED display lamp prompts whether the line has irregular load or not based on different colors and executes the report operation of the superior system.
6. The power system load detection circuit of claim 2, wherein the actuator (140) comprises an LED display.
7. The load detection circuit of claim 1, wherein the second frequency ranges from 500KHz to 30MHz, and the first frequency ranges from less than 500 KHz.
8. The load detection circuit of the power system according to claim 1, wherein the control circuit (130) comprises an MCU or a CPU.
9. The load detection circuit of an electric power system according to claim 1, characterized in that the load detection circuit (100) is adapted for low voltage lines.
10. Electrical power system, characterized in that it comprises a load detection circuit (100) of an electrical power system according to any of claims 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021511686.8U CN213069056U (en) | 2020-07-27 | 2020-07-27 | Power system and load detection circuit thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021511686.8U CN213069056U (en) | 2020-07-27 | 2020-07-27 | Power system and load detection circuit thereof |
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| Publication Number | Publication Date |
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| CN213069056U true CN213069056U (en) | 2021-04-27 |
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| CN202021511686.8U Active CN213069056U (en) | 2020-07-27 | 2020-07-27 | Power system and load detection circuit thereof |
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| CN (1) | CN213069056U (en) |
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