CN109709374B - Residual voltage detection circuit - Google Patents
Residual voltage detection circuit Download PDFInfo
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- CN109709374B CN109709374B CN201910053783.2A CN201910053783A CN109709374B CN 109709374 B CN109709374 B CN 109709374B CN 201910053783 A CN201910053783 A CN 201910053783A CN 109709374 B CN109709374 B CN 109709374B
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Abstract
The invention discloses a residual voltage detection circuit connected with a power distribution terminal, which comprises an energy storage unit and a magnetic latching relay, wherein the energy storage unit is connected with a power distribution terminal; under the power-off state of the power distribution terminal, the energy storage unit can provide electric energy for the attraction of the closing coil, and the residual voltage signal output module responds to the closing signal of the closing coil, closes a switch in the residual voltage signal output module and outputs a residual voltage detection signal. The residual voltage detection circuit can detect residual voltage signals without the need of electrification of a terminal.
Description
Technical Field
The invention belongs to the field of distribution line residual voltage detection, and particularly relates to a residual voltage detection circuit.
Background
When a permanent fault point occurs in a distribution line, the distribution terminal immediately responds to control the circuit breaker or the pole-mounted switch to protect and trip, and after a certain time, the line reclosing is started, and if the line is reclosed in a fault, the protection device accelerates tripping. The characteristic is that a fault voltage cycle of a plurality of cycles appears and then disappears, which is called residual voltage. And after the distribution terminal is switched off, whether a residual voltage signal exists in the line or not is monitored in real time, and if the residual voltage signal exists, the line is immediately locked, and the switching-off state is kept.
The existing residual voltage detection circuit can only effectively detect the residual voltage in the electrified state of a power distribution terminal, although the circuit is simple, when the power distribution terminal loses the power, the residual voltage detection circuit can not work continuously.
Disclosure of Invention
The invention aims to provide a residual voltage detection circuit which can detect a residual voltage signal without electrifying a terminal.
In order to solve the problems, the technical scheme of the invention is as follows:
a residual voltage detection circuit is connected with a power distribution terminal and comprises an energy storage unit and a magnetic latching relay;
the magnetic latching relay comprises a closing coil and a residual voltage signal output module, and the residual voltage signal output module responds to a closing signal of the closing coil, closes a switch in the residual voltage signal output module and outputs a residual voltage detection signal;
the energy storage unit is connected with the power distribution terminal, the energy storage unit stores electric quantity provided by the power distribution terminal in the working state of the residual voltage detection circuit, and the energy storage unit provides electric energy for closing the closing coil in an attraction mode in the power loss state of the power distribution terminal.
According to the embodiment provided by the invention, the magnetic latching relay further comprises a reset circuit, and the reset circuit detects the interference signal output by the magnetic latching relay and resets and eliminates the interference signal in the state that the residual voltage detection circuit is electrified for working for the first time.
According to the embodiment provided by the invention, the reset circuit comprises a third triode, a photoelectric coupler and a reset coil;
the photoelectric coupler is provided with a light emitting diode and a light receiving unit, the negative electrode of the light emitting diode is electrically connected with the collector electrode of the third triode, and the positive electrode of the light emitting diode is externally connected with a power supply;
the reset coil is electrically connected with the output end of the light receiving unit;
the reset circuit detects the interference signal to enable the third triode to be conducted, the light emitting diode is conducted, the light receiving unit is conducted, the reset coil resets to eliminate the interference signal, and the switch in the residual voltage signal output module is switched off.
According to the embodiment provided by the invention, the residual voltage detection circuit further comprises a switching-on driving circuit, wherein the switching-on driving circuit comprises a first voltage-regulator tube and a second triode;
a collector of the second triode is electrically connected with the closing coil;
the cathode of the first voltage-stabilizing tube is electrically connected with the base level of the second triode, and the anode of the first voltage-stabilizing tube is electrically connected with the emitter level of the second triode;
and in the working state of the residual voltage detection circuit, the residual voltage signal passes through the first voltage-regulator tube, a voltage difference is generated between the base electrode of the second triode and the emitter of the second triode, the second triode is conducted, and the closing coil is conducted.
According to the embodiment provided by the invention, the residual voltage detection circuit further comprises a turn-off circuit, wherein the turn-off circuit comprises a second capacitor, a second voltage regulator tube and a first triode;
the collector electrode of the first triode is electrically connected with the base electrode of the second triode, the base electrode of the first triode is electrically connected with the negative electrode of the second voltage-regulator tube, and the emitter electrode of the first triode is electrically connected with the positive electrode of the second voltage-regulator tube;
the anode of the second capacitor is electrically connected with the cathode of the second voltage-stabilizing tube, and the cathode of the second capacitor is electrically connected with the anode of the second voltage-stabilizing tube;
in the state that the second capacitor is charged, the first triode is cut off, the second triode is conducted, and the residual voltage signal output module outputs the residual voltage detection signal; and the number of the first and second groups,
and under the state that the second capacitor is charged to be saturated, the first triode is conducted, the second triode is cut off, and the switch in the residual voltage signal output module is disconnected.
According to the embodiment of the present invention, the energy storage unit is a first capacitor, a positive electrode of the first capacitor is electrically connected to a positive electrode of a rectifying circuit in the residual voltage detection circuit, and a negative electrode of the first capacitor is electrically connected to a negative electrode of the rectifying circuit.
Due to the adoption of the technical scheme, compared with the prior art, the invention has the following advantages and positive effects:
1) the energy storage unit in one embodiment of the invention is connected with the power distribution terminal, can store electric quantity and also can provide electric quantity for the attraction of the closing coil when the power distribution terminal loses power, and the residual voltage signal output module in the magnetic latching relay responds to the closing signal of the closing coil, closes the switch in the residual voltage signal output module and outputs a residual voltage detection signal. The residual voltage detection circuit can detect residual voltage signals without the need of electrification of a terminal.
2) In an embodiment of the present invention, the reset circuit detects an interference signal output by the magnetic latching relay when the detection circuit is powered on for the first time, and resets and eliminates the interference signal. The detection circuit can be prevented from misinterpreting the interference signal as a residual voltage signal.
3) In an embodiment of the present invention, in a state where the second capacitor is charged, a base voltage of the first triode is close to zero potential during charging of the second capacitor, and is kept in a cut-off state, when the second capacitor is saturated, the base voltage of the first triode rises to a cut-off voltage of the second voltage regulator tube, the first triode is turned on, and the second triode is cut off due to loss of voltage of the base, so as to turn off a switch in the residual voltage signal output module. The closing coil of the magnetic latching relay can be prevented from being in a live working state for a long time.
Drawings
FIG. 1 is a schematic diagram of a residual voltage detection circuit according to the present invention;
fig. 2 is a schematic diagram of a reset circuit according to an embodiment of the invention.
Detailed Description
The following describes a residual voltage detection circuit according to the present invention in detail with reference to the accompanying drawings and specific embodiments. Advantages and features of the present invention will become apparent from the following description and from the claims.
Referring to fig. 1, a residual voltage detection circuit, connected to a power distribution terminal, includes an energy storage unit and a magnetic latching RELAY relax 1; magnetic latching RELAY RELAY1 includes closing coil and residual voltage signal output module, residual voltage signal output module responds to the closed signal of closing coil, the switch among the closed residual voltage signal output module to output residual voltage detected signal, the energy storage unit links to each other with distribution terminal, under the state of residual voltage detected circuit work, the electric quantity that the energy storage unit storage distribution terminal provided, under the state that distribution terminal loses the electricity, the actuation of energy storage unit to closing coil provides the electric energy. Because the time of the circuit outputting the residual voltage is very short, under the condition that the power distribution terminal loses power, the energy provided by the energy storage unit only needs to meet the time of the residual voltage output, and therefore the energy storage unit in the embodiment adopts the first capacitor C1. The positive electrode of the first capacitor C1 is electrically connected with the positive electrode of the diode rectifier bridge BR1 of the residual voltage detection circuit, and the negative electrode of the first capacitor C1 is electrically connected with the negative electrode of the diode rectifier bridge BR 1.
It can be understood that, the energy storage unit in this embodiment is connected to the power distribution terminal, and can store electric quantity, and also can provide electric quantity for the attraction of the closing coil when the power distribution terminal loses power, and the residual voltage signal output module in the magnetic latching RELAY1 responds to the closing signal of the closing coil, closes the switch in the residual voltage signal output module, and outputs a residual voltage detection signal. The residual voltage detection circuit can detect residual voltage signals without the need of electrification of a terminal.
Because the closing coil of the magnetic latching RELAY RELAY1 can also act when the power is normally powered on for the first time, a non-residual voltage signal is generated at the output end of the magnetic latching RELAY RELAY1 and is kept, the non-residual voltage signal is called as an interference signal here, the interference signal needs to be reset and eliminated, and the situation that the interference signal is mistakenly judged as a residual voltage signal by a residual voltage detection circuit is avoided. Therefore, referring to fig. 2, fig. 2 is a schematic diagram of a reset circuit in the present embodiment, the reset circuit includes a third transistor V1, a photo coupler OP1, and a reset coil; the photoelectric coupler is provided with a light emitting diode and a light receiving unit, the negative electrode of the light emitting diode is electrically connected with the collector electrode of the third triode V1, the positive electrode of the light emitting diode is externally connected with a power supply, the reset coil is electrically connected with the output end of the light receiving unit, the reset circuit detects an interference signal to enable the third triode V1 to be conducted, the light emitting diode is conducted, the light receiving unit is conducted, the reset coil resets to eliminate the interference signal, and the switch in the residual voltage signal output module is disconnected. Preferably, the light receiving unit in this embodiment is a photosensitive transistor, and of course, in other embodiments, the light receiving unit is a photosensitive resistor, which also falls within the protection scope of the present invention.
The reset circuit in this embodiment detects an interference signal output by the magnetic latching relay when the detection circuit is powered on for the first time, and resets and eliminates the interference signal. The detection circuit can be prevented from misinterpreting the interference signal as a residual voltage signal.
Further, the residual voltage detection circuit further comprises a switching-on driving circuit and a switching-off circuit, wherein the switching-on driving circuit comprises a second resistor R2, a third resistor R4, a first voltage regulator tube ZD1 and a second triode Q2; the collector of the second triode Q2 is electrically connected with the switching-on coil, the cathode of the first voltage-regulator tube ZD1 is electrically connected with the base of the second triode Q2, the anode of the first voltage-regulator tube ZD1 is electrically connected with the emitter of the second triode Q2, the first end of the second resistor R2 is electrically connected with the switching-on coil, the second end of the second resistor R2 is electrically connected with the base of the second triode Q2, the first end of the third resistor R4 is electrically connected with the base of the second triode Q2, the second end of the third resistor R4 is electrically connected with the anode of the first voltage-regulator tube ZD1, when the residual voltage detection circuit works, a residual voltage signal passes through the first voltage-regulator tube ZD1, a voltage difference is generated between the base of the second triode Q2 and the emitter of the second triode Q2, the second triode Q2 is conducted, and the switching-on coil is conducted.
The first voltage regulator tube ZD1 can clamp the base of the second triode Q2 to prevent the second triode Q2 from being damaged due to overhigh voltage, and the second resistor R2 and the third resistor R4 can properly delay the conduction time of the second triode Q2 to ensure that the first capacitor C1 can fully absorb energy when a residual voltage signal exists in the circuit, so that the first capacitor C1 can conduct a closing coil in the magnetic latching RELAY1 to output the residual voltage signal under the condition that the power distribution terminal is out of power.
The turn-off circuit comprises a first resistor R1, a second capacitor C2, a second voltage regulator tube ZD2 and a first triode Q1; the first end of the first resistor R1 is electrically connected with the anode of the first capacitor C1, the second end of the first resistor R1 is electrically connected with the anode of the second capacitor C2, the collector of the first triode Q1 is electrically connected with the base of the second triode Q2, the base of the first triode Q1 is electrically connected with the cathode of the second voltage regulator ZD2, the emitter of the first triode Q1 is electrically connected with the anode of the second voltage regulator ZD2, the anode of the second capacitor C2 is electrically connected with the cathode of the second voltage regulator ZD2, the cathode of the second capacitor C2 is electrically connected with the anode of the second voltage regulator ZD2, under the state that the first resistor R1 and the second capacitor C2 are charged, the first transistor Q1 is cut off, the second transistor Q2 is conducted, the residual voltage signal output module outputs a residual voltage detection signal, and, under the state that the first resistor R1 and the second capacitor C2 are charged to saturation, the first triode Q1 is turned on, the second triode Q2 is turned off, and the switch in the residual voltage signal output module is turned off.
When the detection circuit is normally powered on, if a turn-off measure is not taken for the second triode Q2, the closing coil is in a charged working state for a long time, and a residual voltage signal is always output, so that the conventional magnetic latching RELAY1 may be damaged due to overheating. In the present embodiment, in the state where the second capacitor C2 is charged, the base voltage of the first triode Q1 approaches zero potential during the charging period of the second capacitor C2, and keeps the off state, when the second capacitor C2 is saturated, the base voltage of the first triode Q1 rises to the off voltage of the second voltage regulator ZD2, the first triode Q1 is turned on, and the second triode Q2 is turned off due to the base voltage loss, so as to turn off the switch in the residual voltage signal output module. The closing coil of the magnetic latching RELAY1 can be prevented from being in a charged working state for a long time.
The residual voltage detection circuit also comprises a linear transformer T1, and the winding transformation ratio of the linear transformer T1 can be flexibly designed according to the actual residual voltage trigger voltage. The power consumption can be calculated according to the resistance values of the second resistor R2 and the third resistor R4 in the circuit,
wherein, UdcThe calculation method comprises the following steps:
wherein, UdcRepresents the input voltage of the residual voltage detection circuit,
the ratio of the numbers of the primary and secondary sides.
Under normal operation, assuming that the winding transformation ratio N2/N1 of the linear transformer T1 is 1/2, U isdcFor 156V, assuming that the second resistor R2 and the third resistor R4 are both 75k Ω, the calculated power consumption P is 1.04mW, whereas the power consumption of the existing residual voltage detection circuit is generally tens mW, and compared with the existing residual voltage detection circuit, the residual voltage detection circuit in this embodiment has low power consumption, and does not cause any adverse effect on the system, and the trigger voltage may be set to any fixed value according to the requirement.
The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, it is still within the scope of the present invention if they fall within the scope of the claims of the present invention and their equivalents.
Claims (2)
1. A residual voltage detection circuit is connected with a power distribution terminal and is characterized by comprising an energy storage unit, a magnetic latching relay and a reset circuit;
the magnetic latching relay comprises a closing coil and a residual voltage signal output module, and the residual voltage signal output module responds to a closing signal of the closing coil, closes a switch in the residual voltage signal output module and outputs a residual voltage detection signal;
the energy storage unit is connected with the power distribution terminal, stores the electric quantity provided by the power distribution terminal in the working state of the residual voltage detection circuit, and provides electric energy for the attraction of the closing coil in the power loss state of the power distribution terminal;
the reset circuit detects the interference signal output by the magnetic latching relay in the state that the residual voltage detection circuit is electrified for working for the first time, and resets and eliminates the interference signal;
the reset circuit comprises a third triode, a photoelectric coupler and a reset coil;
the photoelectric coupler is provided with a light emitting diode and a light receiving unit, the negative electrode of the light emitting diode is electrically connected with the collector electrode of the third triode, and the positive electrode of the light emitting diode is externally connected with a power supply;
the reset coil is electrically connected with the output end of the light receiving unit;
the reset circuit detects the interference signal to enable the third triode to be conducted, the light emitting diode is conducted, so that the light receiving unit is conducted, the reset coil resets to eliminate the interference signal, and a switch in the residual voltage signal output module is switched off; the circuit also comprises a switching-on driving circuit, wherein the switching-on driving circuit comprises a first voltage-stabilizing tube and a second triode;
a collector of the second triode is electrically connected with the closing coil;
the cathode of the first voltage-stabilizing tube is electrically connected with the base level of the second triode, and the anode of the first voltage-stabilizing tube is electrically connected with the emitter level of the second triode;
when the residual voltage detection circuit works, the residual voltage signal passes through the first voltage-regulator tube, a voltage difference is generated between the base electrode of the second triode and the emitter of the second triode, the second triode is conducted, and the closing coil is conducted;
the circuit also comprises a turn-off circuit, wherein the turn-off circuit comprises a second capacitor, a second voltage regulator tube and a first triode;
the collector electrode of the first triode is electrically connected with the base electrode of the second triode, the base electrode of the first triode is electrically connected with the negative electrode of the second voltage-regulator tube, and the emitter electrode of the first triode is electrically connected with the positive electrode of the second voltage-regulator tube;
the anode of the second capacitor is electrically connected with the cathode of the second voltage-stabilizing tube, and the cathode of the second capacitor is electrically connected with the anode of the second voltage-stabilizing tube;
in the state that the second capacitor is charged, the first triode is cut off, the second triode is conducted, and the residual voltage signal output module outputs the residual voltage detection signal; and the number of the first and second groups,
and under the state that the second capacitor is charged to be saturated, the first triode is conducted, the second triode is cut off, and the switch in the residual voltage signal output module is disconnected.
2. The residual voltage detection circuit according to claim 1, wherein said energy storage unit is a first capacitor, an anode of said first capacitor is electrically connected to an anode of a rectifying circuit in said residual voltage detection circuit, and a cathode of said first capacitor is electrically connected to a cathode of said rectifying circuit.
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| CN201910053783.2A CN109709374B (en) | 2019-01-21 | 2019-01-21 | Residual voltage detection circuit |
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| CN201910053783.2A CN109709374B (en) | 2019-01-21 | 2019-01-21 | Residual voltage detection circuit |
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| CN109709374B true CN109709374B (en) | 2021-03-16 |
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| CN111983297B (en) * | 2020-08-21 | 2023-09-08 | 重庆新世杰电气股份有限公司 | Instantaneous residual pressure detection method, device and equipment |
| CN115201548B (en) * | 2022-09-14 | 2022-11-29 | 石家庄科林电气股份有限公司 | Residual voltage detection recording device and method for power distribution terminal |
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| CN207068748U (en) * | 2017-03-15 | 2018-03-02 | 珠海思创电气有限公司 | A kind of drive circuit for reducing power consumption of electromagnetic relay |
| US9947350B1 (en) * | 2016-12-16 | 2018-04-17 | Stmicroelectronics S.R.L. | Method of detecting back electromotive force in electro-mechanical actuators, corresponding device and apparatus |
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| CN206481046U (en) * | 2016-12-08 | 2017-09-08 | 南昌工程学院 | High-voltage circuit breaker coil protective device and protection system |
| US9947350B1 (en) * | 2016-12-16 | 2018-04-17 | Stmicroelectronics S.R.L. | Method of detecting back electromotive force in electro-mechanical actuators, corresponding device and apparatus |
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