CN209748192U - Alternating current prevention grid connection device for direct current power supply system - Google Patents
Alternating current prevention grid connection device for direct current power supply system Download PDFInfo
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- CN209748192U CN209748192U CN201920295323.6U CN201920295323U CN209748192U CN 209748192 U CN209748192 U CN 209748192U CN 201920295323 U CN201920295323 U CN 201920295323U CN 209748192 U CN209748192 U CN 209748192U
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Abstract
The utility model provides a prevent alternating current grid-connected device for direct current supply system, wherein direct current supply system has diode D including diode D1 and the filter electrolytic capacitor C1 of establishing ties, and its characterized in that includes filter electrolytic capacitor C1 both ends parallel connection, and diode D's negative pole and diode D1's negative pole electricity connection, diode D's both ends parallel connection have inductance L and electric capacity C of establishing ties each other. The utility model aims at providing a prevent alternating current grid-connected device for direct current power supply system to the defect of prior art, effectively avoid stealing the anti-power transmission behind the electricity, the opposite phase arouses equipment trouble.
Description
Technical Field
The invention relates to the technical field of power system protection, in particular to an alternating current prevention grid-connected device for a direct current power supply system.
Background
The street lamp is powered by alternating current and direct current in an isolated manner, and does not form a loop with the ground, so that the street lamp is relatively safe. But because the power supply network is distributed throughout the streets of each cell in the city: various electricity stealing phenomena occur in some cases. The phenomenon of alternating current reverse power transmission also occurs in the processes of power charging and electricity stealing: the normal operation of the power grid is seriously damaged by burning out the direct current device.
Disclosure of Invention
The invention aims to overcome the defects of the existing direct-current power supply technology, and provides an alternating-current prevention grid-connected device for a direct-current power supply system, which effectively avoids alternating-current reverse power transmission caused by power mismatching and power stealing.
The invention provides an alternating current prevention grid-connected device for a direct current power supply system, wherein the direct current power supply system comprises a diode D1 and a filter electrolytic capacitor C1 which are connected in series, and the alternating current prevention grid-connected device is characterized by comprising a filter electrolytic capacitor C1, wherein two ends of the filter electrolytic capacitor C1 are connected with the diode D in parallel, the cathode of the diode D is connected with the cathode of a diode D1, two ends of the diode D are connected with an inductor L and a capacitor C which are connected in series, and two ends of the capacitor C are used as the output end of the direct current power supply system.
In the technical scheme, the device further comprises a photoelectric coupler, an MCU and a driving module, wherein the photoelectric coupler is connected in parallel with two ends of the capacitor C, the cathode of a photosensitive diode of the photoelectric coupler is electrically connected with the cathode of the diode D through an inductor L, the anode of the photosensitive diode of the photoelectric coupler is electrically connected with the anode of the diode D, the output end of the photoelectric coupler is electrically connected with the signal input end of the MCU, and the output end of the MCU is electrically connected with the driving module; a switch K is arranged between the capacitor C and the diode, the MCU receives a signal from the photoelectric coupler and then sends a command of disconnecting the switch to the driving module, and the driving module drives the switch K to be disconnected according to the command.
In the technical scheme, the power supply further comprises a current transformer, wherein the input end of the current transformer is connected in parallel to the two ends of the capacitor C through a capacitor C2, the output end of the current transformer is electrically connected to the signal input end of the MCU, the MCU sends a switch-off command to the driving module after receiving a level signal from the current transformer, and the driving module drives the switch K to be switched off according to the command; and the MCU sends a command of recovering the switch to the driving module after not receiving the level signal from the current transformer, and the driving module drives the switch K according to the command.
In the technical scheme, two ends of a capacitor C are connected in parallel with a resistor R1 and a voltage regulator tube which are connected in series, wherein the cathode of the voltage regulator tube is electrically connected with the cathode of a photosensitive diode of the photoelectric coupler, and the anode of the voltage regulator tube is electrically connected with the anode of the photosensitive diode of the photoelectric coupler.
In the technical scheme, the cathode of the voltage stabilizing tube is electrically connected with the cathode of a photosensitive diode of the photoelectric coupler through the resistor R2, the conduction time of the photoelectric coupler is adjusted by setting the ratio of the resistor R1 to the resistor R2, and the conduction time of the photoelectric coupler is guaranteed to be greatly smaller than one fourth of the reverse phase period of alternating current power supply.
In the technical scheme, the power supply further comprises an external power supply, and the external power supply respectively supplies power to the MCU and the photoelectric coupler.
In the technical scheme, the MCU is further electrically connected with a wireless communication module, and the MCU sends the electricity stealing condition to an external platform through the wireless communication module.
In the technical scheme, the switch K adopts a bipolar transistor, a mos tube, an IGBT tube or other high-speed electronic switches, and a thyristor is not allowed to be used.
According to the technical scheme, the protection resistor is arranged between the output end of the direct current power supply system and the capacitor, two ends of the protection resistor are electrically connected with the input end of the MCU respectively and used for judging current flowing through the protection resistor, if the current flowing through the protection resistor exceeds the set value inside the MCU, the MCU sends a command of disconnecting the switch to the driving module, and the driving module drives the switch K to be disconnected according to the command.
When the positive half cycle of the alternating current power supply is in phase with the alternating current power supply, the direct current power supply and the alternating current power supply are equivalent to two groups of power supplies for a power system, and the system cannot be damaged. According to the invention, the diodes D are connected in parallel at the two ends of the filter capacitor at the terminal of the direct current power supply output system, so that when the reverse voltage is applied, the diodes D are conducted, namely, the diodes D are equivalent to short circuits to the filter electrolytic capacitor C1, and the influence on the filter electrolytic capacitor C1 is avoided. And simultaneously, the inductor L and the capacitor C form a parallel load, so that a power system is protected. When the photoelectric coupler is in a normal phase, the optical coupler is cut off, the reverse optical coupler diode is conducted to send a reverse signal to the MCU, the MCU sends a signal for cutting off the K, and meanwhile, an alarm signal is sent out through the wireless module, so that related workers can know the electricity stealing condition in time. No output is generated when the current transformer is in a direct current state, and an alternating current signal is provided for the MCU if alternating current feedback is not released; when the alternating current reverse power transmission is released, no alternating current signal exists, the automatic reset is realized, namely, the closing of the switch K is recovered, and the normal use of the power system is ensured.
Drawings
FIG. 1 is a schematic view of the present invention.
Detailed Description
The invention will be further described in detail with reference to the following drawings and specific examples, which are not intended to limit the invention, but are for clear understanding.
As shown in fig. 1, the present invention provides an ac grid connection preventing device for a dc power supply system, wherein the dc power supply system includes a diode D1 and a filtering electrolytic capacitor C1 connected in series, and is characterized in that two ends of the filtering electrolytic capacitor C1 are connected in parallel with a diode D, a cathode of the diode D is connected with a cathode of a diode D1, and two ends of the diode D are connected in parallel with an inductor L and a capacitor C connected in series. And the capacitor C is used as the output end of the direct current power supply system. When the positive half cycle of the alternating current power supply is in phase with the alternating current power supply, the direct current power supply and the alternating current power supply are equivalent to two groups of power supplies for a power system, and the system cannot be damaged. According to the invention, the diodes D are connected in parallel at the two ends of the filter capacitor at the terminal of the direct current power supply output system, so that when the reverse voltage is applied, the diodes D are conducted, namely, the diodes D are equivalent to short circuits to the filter electrolytic capacitor C1, and the influence on the filter electrolytic capacitor C1 is avoided. Simultaneously, the inductor L and the capacitor C form a parallel load, and the parallel load plays a role in protecting a power system
In the technical scheme, the device further comprises a photoelectric coupler, an MCU and a driving module, wherein the photoelectric coupler is connected in parallel with two ends of the capacitor C, the cathode of a photosensitive diode of the photoelectric coupler is electrically connected with the cathode of the diode D through an inductor L, the anode of the photosensitive diode of the photoelectric coupler is electrically connected with the anode of the diode D, the output end of the photoelectric coupler is electrically connected with the signal input end of the MCU, and the output end of the MCU is electrically connected with the driving module; a switch K is arranged between the capacitor C and the diode, the switch K comprises other high-speed electronic switches such as a bipolar transistor, a mos tube and an IGBT tube, a thyristor is not allowed to be adopted, and the switch K is guaranteed to be capable of reacting in an instant time. In practical application, electricity stealing personnel often connect external alternating current to two ends of the capacitor C, so that the disconnection of an electricity stealing circuit can be realized through the setting of the switch K. And the MCU sends a command of disconnecting the switch to the driving module after receiving the signal from the photoelectric coupler, and the driving module drives the switch K to be disconnected according to the command. The photoelectric coupler is connected in parallel with two ends of a capacitor C, and the capacitor C can play a role in time delay protection. The two ends of the capacitor C are connected in parallel with a resistor R1 and a voltage regulator tube which are connected in series, wherein the cathode of the voltage regulator tube is electrically connected with the cathode of the photosensitive diode of the photoelectric coupler, and the anode of the voltage regulator tube is electrically connected with the anode of the photosensitive diode of the photoelectric coupler. The safety of the photoelectric coupler is further protected by the voltage stabilizing tube. The cathode of the voltage-stabilizing tube is electrically connected with the cathode of a photosensitive diode of the photoelectric coupler through a resistor R2. According to the invention, the conducting time of the photoelectric coupler can be adjusted by setting the ratio of the resistors R1 and R2, so that the conducting time of the photoelectric coupler is greatly shorter than a quarter period of the period of alternating current power supply, namely the photoelectric coupler is conducted before the alternating current reverse phase power supply reaches the peak value, the switch K is effectively cut off, and a direct current power supply system is protected.
In the technical scheme, the power supply further comprises a current transformer, wherein the input end of the current transformer is connected in parallel to the two ends of the capacitor C through a capacitor C2, the output end of the current transformer is electrically connected to the signal input end of the MCU, the MCU sends a switch-off command to the driving module after receiving a low-level signal from the current transformer, and the driving module drives the switch K to be switched off according to the command; and the MCU sends a command of a recovery switch to the driving module after receiving the high-level signal from the current transformer, and the driving module drives the switch K to be closed according to the command. When the external part of the direct current power supply system is not connected with the alternating current system, the output voltage of the current transformer is 0; when the external part of the direct current power supply system is connected with an alternating current system, the current transformer outputs a high level signal. And the MCU judges whether to drive the switch K to be switched on or switched off according to the output voltage of the current transformer.
In the technical scheme, the power supply further comprises an external power supply, and the external power supply respectively supplies power to the MCU and the photoelectric coupler to ensure the normal operation of the circuit.
In the technical scheme, the MCU is also electrically connected with a wireless communication module, and the MCU sends an alarm signal to the wireless communication module while sending a command for disconnecting the switch K; the wireless communication module transmits the alarm signal to an external receiving platform, and an operator can receive the alarm information through the external platform, know the electricity stealing condition and react.
Among the above-mentioned technical scheme, be provided with protection resistor between DC power supply system's the output and the electric capacity, protection resistor R3's both ends are connected with MCU's input electricity respectively, a current for judging the protection resistor R3 that flows through, if the current that flows through protection resistor R3 exceeds MCU internal set value, can regard DC power supply system output to connect the AC system or the load that are used for stealing the electricity to appear unusually, MCU sends the order of disconnect switch to drive module, drive module drives the disconnection of switch K according to above-mentioned order.
Details not described in this specification are within the skill of the art that are well known to those skilled in the art.
Claims (9)
1. The alternating current preventing grid-connected device for the direct current power supply system is characterized by comprising a diode D1 and a filtering electrolytic capacitor C1 which are connected in series, wherein the diode D is connected in parallel at two ends of the filtering electrolytic capacitor C1, the cathode of the diode D is electrically connected with the cathode of the diode D1, an inductor L and a capacitor C which are connected in series with each other are connected in parallel at two ends of the diode D, and two ends of the capacitor C are used as output ends of the direct current power supply system.
2. The alternating current preventing grid-connected device for the direct current power supply system according to claim 1, further comprising a photoelectric coupler, an MCU and a driving module, wherein the photoelectric coupler is connected in parallel with two ends of the capacitor C, a cathode of a photosensitive diode of the photoelectric coupler is electrically connected with a cathode of the diode D through an inductor L, an anode of the photosensitive diode of the photoelectric coupler is electrically connected with an anode of the diode D, an output end of the photoelectric coupler is electrically connected with a signal input end of the MCU, and an output end of the MCU is electrically connected with the driving module; a switch K is arranged between the capacitor C and the diode, the MCU receives a signal from the photoelectric coupler and then sends a command of disconnecting the switch to the driving module, and the driving module drives the switch K to be disconnected according to the command.
3. The alternating current grid-connection preventing device for the direct current power supply system according to claim 2, characterized by further comprising a current transformer, wherein an input end of the current transformer is connected in parallel to two ends of the capacitor C through a capacitor C2, an output end of the current transformer is electrically connected to a signal input end of the MCU, the MCU receives a level signal from the current transformer and then sends a command of disconnecting the switch to the driving module, and the driving module drives the switch K to be disconnected according to the command; and the MCU sends a command of recovering the switch to the driving module after not receiving the level signal from the current transformer, and the driving module drives the switch K according to the command.
4. The alternating current preventing grid connection device for the direct current power supply system according to claim 2, wherein two ends of the capacitor C are connected in parallel with a resistor R1 and a voltage regulator tube which are connected in series with each other, wherein a cathode of the voltage regulator tube is electrically connected with a cathode of a photodiode of the photoelectric coupler, and an anode of the voltage regulator tube is electrically connected with an anode of the photodiode of the photoelectric coupler.
5. The alternating current prevention grid connection device for the direct current power supply system according to claim 4, wherein a cathode of the voltage regulator tube is electrically connected with a cathode of a photosensitive diode of the photoelectric coupler through a resistor R2, and the conduction time of the photoelectric coupler is adjusted by setting a ratio of a resistor R1 to a resistor R2, so that the conduction time of the photoelectric coupler is greatly less than one fourth of an alternating current supply reverse phase period.
6. The alternating current prevention grid connection device for the direct current power supply system according to claim 4, further comprising an external power supply which supplies power to the MCU and the photocoupler, respectively.
7. The alternating current prevention grid-connected device for the direct current power supply system according to claim 6, wherein the MCU is further electrically connected with a wireless communication module, and the MCU sends the electricity stealing condition to an external platform through the wireless communication module.
8. The alternating current grid connection prevention device for the direct current power supply system according to claim 6, wherein the switch K is a bipolar transistor, a mos transistor, an IGBT (insulated gate bipolar transistor) or other high-speed electronic switches, and a thyristor is not allowed.
9. The alternating current prevention grid connection device for the direct current power supply system according to claim 3, wherein a protection resistor is arranged between the output end of the direct current power supply system and the capacitor, two ends of the protection resistor are respectively electrically connected with the input end of the MCU and used for judging the current flowing through the protection resistor, if the current flowing through the protection resistor exceeds the set value inside the MCU, the MCU sends a command of disconnecting the switch to the driving module, and the driving module drives the switch K to be disconnected according to the command.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201920295323.6U CN209748192U (en) | 2019-03-08 | 2019-03-08 | Alternating current prevention grid connection device for direct current power supply system |
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| CN201920295323.6U CN209748192U (en) | 2019-03-08 | 2019-03-08 | Alternating current prevention grid connection device for direct current power supply system |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109861197A (en) * | 2019-03-08 | 2019-06-07 | 武汉市路灯管理服务中心 | Anti- alternating current grid-connecting apparatus for DC power-supply system |
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- 2019-03-08 CN CN201920295323.6U patent/CN209748192U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109861197A (en) * | 2019-03-08 | 2019-06-07 | 武汉市路灯管理服务中心 | Anti- alternating current grid-connecting apparatus for DC power-supply system |
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