CN211263671U - Electric power direct current screen direct current bus insulation detection circuit - Google Patents
Electric power direct current screen direct current bus insulation detection circuit Download PDFInfo
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- CN211263671U CN211263671U CN201920065168.9U CN201920065168U CN211263671U CN 211263671 U CN211263671 U CN 211263671U CN 201920065168 U CN201920065168 U CN 201920065168U CN 211263671 U CN211263671 U CN 211263671U
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Abstract
The utility model discloses an electric power direct current screen direct current bus insulation detection circuit, the circuit includes the balanced bridge circuit that is formed by connecting in series positive pole line switching relay, negative pole line switching relay, four 15k omega/2W metal film power resistors, the unbalanced bridge circuit that is formed by connecting in series positive pole switching relay, negative pole switching relay, four 68k omega/2W metal film power resistors, measure two voltage measurement circuits of positive bus to ground, negative bus to ground; when the CPU of the controller controls the input/output of the balance bridge and the unbalance bridge, the two voltage measuring circuits detect the ground insulation condition of the direct current bus. The utility model discloses can detect the single-ended ground connection of direct current bus, the insulating reduction situation of balanced ground connection more accurately.
Description
Technical Field
The utility model relates to an electric power direct current screen direct current bus insulation detection circuitry, single-ended ground connection detection and the balanced ground connection detection of bi-polar including direct current bus.
Background
The electric power direct current screen outputs 220V/110V direct current voltage, and provides uninterrupted constant direct current power supply for loads such as electric control, signals, measurement and relay protection, an automatic device, an operating mechanism direct current motor, a breaker electromagnetic operated closing mechanism, an alternating current uninterrupted power supply system, a telecontrol device power supply, emergency lighting and the like.
In a 220V/110V electric power direct current screen, a direct current bus is used for converging, and a charging module, a storage battery pack and a multi-path feeder line branch are connected to the direct current bus in parallel. The current output of the charging module and the storage battery pack flows into each feeder line branch after converging through a direct current bus, and supplies power to a load after passing through an air switch of the miniature circuit breaker.
Because the rear end of each feeder line branch is complicated in wiring and connected with various load devices, the condition of grounding due to insulation reduction is easy to occur, and a common fault is one-point grounding. In general, a point ground does not affect the operation of the dc system. However, if the earth fault point cannot be found and repaired quickly and another earth fault point occurs, the false operation of the signal circuit, the control circuit, the relay protection device and other devices may be caused, thereby damaging the safe operation of the power system and even causing a large-scale power failure accident. Therefore, it is necessary to add a dc bus insulation detection device to detect a single-ended ground fault or a double-ended balanced ground fault of the dc bus.
The existing direct current bus insulation detection equipment cannot accurately detect the abnormalities of single-ended direct grounding, single-ended resistance grounding, double-ended grounding and the like of a direct current bus.
SUMMERY OF THE UTILITY MODEL
The utility model aims to solve the technical problem that an electric power direct current screen direct current bus insulation detection circuitry is provided, its single-ended direct ground connection, single-ended resistance ground connection, double-ended ground connection etc. that can detect out electric power direct current screen direct current bus more accurately are unusual.
Solve above-mentioned technical problem, the utility model discloses the technical scheme who adopts as follows:
a circuit for detecting insulation of a direct current bus is characterized by comprising:
a controller CPU (U6);
the balance bridge circuit is composed of a positive line (KM +110) switching relay (K3), a negative line (KM-110) switching relay (K4) and first to fourth balance resistors (R100, R101, R102 and R103), wherein one end of each of the first to fourth balance resistors is connected with a normally closed contact of the switching relay (K3) after being sequentially connected in series, and the other end of each of the first to fourth balance resistors is connected with a normally closed contact of the switching relay (K4); the connection point of the second and third balance resistors (R101 and R102) is connected with the Earth (Earth), and the two switching relays (K3 and K4) are connected and controlled by a controller CPU (U6): when the device normally operates, the two switching relays (K3 and K4) do not act, and the contacts are normally closed;
the unbalanced bridge circuit is composed of a positive-end switching relay (K2), a negative-end switching relay (K5) and first to fourth unbalanced resistors (R110, R111, R112 and R113), wherein the first to fourth unbalanced resistors are sequentially connected in series, one end of each unbalanced resistor is connected with a normally open contact of the switching relay (K2), the other end of each unbalanced resistor is connected with a normally open contact of the switching relay (K5), a connecting point of the second unbalanced resistor (R111) and the third unbalanced resistor (R112) is connected with the Earth (Earth), and the two switching relays (K2 and K5) are controlled by a CPU (U6); when the device normally operates, the two switching relays (K2 and K5) do not act, and the contacts are normally opened; when a positive bus unbalanced bridge is put into, a switching relay (K2) acts, and a contact of the switching relay is closed; when a negative bus unbalanced bridge is put into, a switching relay (K5) acts, and a contact of the switching relay is attracted;
a positive bus-to-ground voltage acquisition loop which is connected in parallel to the positive line KM +110 and the ground;
a negative bus voltage-to-ground voltage acquisition loop which is connected in parallel with the negative line KM-110 and the ground;
a status signal input circuit: two output ends 1 and 2 of the connecting terminal (CN3) are respectively connected with the cathode of an anti-reflection diode (D2) and a current-limiting resistor (R37) in series after being connected with a transient suppression diode (TVS10) in parallel, and finally connected with an isolation optocoupler (U30); one port of the isolation optocoupler (U30) is grounded, and the other port of the isolation optocoupler (U30) is connected with P3.3V voltage; and the X0 is connected to a controller CPU (U6), and when a state input signal exists, the controller CPU (U6) controls two switching relays of the balance bridge circuit to act simultaneously (K3 and K4), and the contacts are separated.
The structure that the positive bus-to-ground voltage acquisition loop is connected in parallel to the positive line KM +110 and the ground is as follows: the positive electrode line KM +110 and the ground are respectively connected to a first positive electrode line operational amplifier, and the first operational amplifier is connected to the controller after passing through a linear optical coupler and a second positive electrode line operational amplifier;
the structure that the negative bus voltage-to-ground voltage acquisition loop is connected in parallel to the negative line KM +110 and the ground is as follows: the negative electrode line KM +110 and the ground are respectively connected into a first negative electrode line operational amplifier, and the first operational amplifier is connected into the controller after passing through a linear optical coupler and a second negative electrode line operational amplifier.
The first to fourth balanced resistors (R100, R101, R102, R103) are four power resistors of 15k omega/2W metal film, and the first to fourth unbalanced resistors R110, R111, R112, R113 are four power resistors of 68k omega/2W metal film.
The controller CPU is a 32-bit ARM series STM32F103 chip, the voltage sampling loop is isolated by a linear optocoupler HCNR201 chip, the state signal input loop is isolated by a TLP521 optocoupler, and the switching relay is HF 41F/24-ZS.
The principle of the utility model is that: firstly, a controller CPU program controls a positive line (KM +110) switching relay (K3) and a negative line (KM-110) switching relay (K4) to be put into operation. At the moment, a balance bridge circuit formed by connecting four 15k omega/2W metal film power resistors (R100, R101, R102 and R103) in series is connected into the direct current bus, the positive voltage to ground and the negative voltage to ground of the direct current bus are detected by two voltage measuring circuits, and the single-end ground insulation condition of the direct current bus is calculated. And then, a controller CPU (U6) controls a positive end switching relay (K2) to be switched in, at the moment, two 68K omega/2W metal film power resistors (R110, R111) are connected to the direct current bus, and two voltage measuring circuits detect the positive voltage-to-ground voltage U1 and the negative voltage-to-ground voltage U2 of the direct current bus. And then, the relay (K2) and the power resistors (R110 and R111) are disconnected, a negative terminal switching relay (K5) and two 68K omega/2W metal film power resistors (R112 and R113) are put in, the positive earth voltage U3 and the negative earth voltage U4 of the direct current bus are detected by two voltage measuring circuits, and the double-end grounding condition of the direct current bus is calculated through four voltage values of U1, U2, U3 and U4.
Compared with the prior art, the utility model discloses following beneficial effect has:
1. the utility model discloses constitute balanced bridge circuit by two relays and four 15k omega 2W metal film power resistance, constitute unbalanced bridge circuit by two relays and four 68k omega 2W metal film power resistance, balanced bridge and the input/withdraw of unbalanced bridge circuit are controlled by controller CPU 6; the technical specification requirement of the direct current screen of the power system is met.
2. The sampling circuit of the positive and negative buses to the ground voltage is isolated by the linear optocoupler, so that the complete isolation of the primary power supply and the secondary power supply is realized, and the device is more stable.
Drawings
Fig. 1 is a circuit diagram of a balanced bridge and an unbalanced bridge of the present invention;
fig. 2 is a circuit diagram of the status signal input circuit of the present invention;
fig. 3 is a schematic diagram of a positive and negative bus voltage to ground voltage acquisition circuit according to an embodiment of the present invention;
fig. 4 is a positive and negative bus voltage to ground voltage acquisition loop according to an embodiment of the present invention.
Detailed Description
The present invention will be further described with reference to the following examples.
Referring to fig. 1 to 4, the circuit embodiment of the dc bus insulation detection of the present invention includes:
a controller CPUU 6;
the balance bridge circuit is composed of a positive electrode line KM +110 switching relay K3, a negative electrode line KM-110 switching relay K4 and first to fourth balance resistors R100, R101, R102 and R103, wherein the first to fourth balance resistors are sequentially connected in series, and then one end of each balance resistor is connected with a normally closed contact of the switching relay K3, and the other end of each balance resistor is connected with a normally closed contact of the switching relay K4; the connection point of the second and third balance resistors R101 and R102 is connected with Earth, and the two switching relays K3 and K4 are connected and controlled by a controller CPU U6: when the device normally operates, the two switching relays K3 and K4 do not act, and the contacts are normally closed;
the unbalanced bridge circuit is composed of a positive end switching relay K2, a negative end switching relay K5, first to fourth unbalanced resistors R110, R111, R112 and R113, wherein the first to fourth unbalanced resistors are sequentially connected in series, one end of each unbalanced resistor is connected with a normally open contact of the switching relay K2, the other end of each unbalanced resistor is connected with a normally open contact of the switching relay K5, a connecting point of the second unbalanced resistor R111 and the third unbalanced resistor R112 is connected with the Earth, and the two switching relays K2 and K5 are controlled by a controller CPU U6; when the device normally operates, the two switching relays K2 and K5 do not act, and the contacts are normally opened; when a positive bus unbalanced bridge is put into, the switching relay K2 acts, and the contact of the switching relay K2 is closed; when a negative bus unbalanced bridge is put into, the switching relay K5 acts, and the contact of the switching relay K5 is closed;
a positive bus-to-ground voltage acquisition loop which is connected in parallel to the positive line KM +110 and the ground;
a negative bus voltage-to-ground voltage acquisition loop which is connected in parallel with the negative line KM-110 and the ground;
a status signal input circuit: after the two output ends 1 and 2 of the connection terminal CN3 are connected in parallel with the transient suppression diode TVS10, the two output ends are respectively connected in series with the cathode of the anti-reverse diode D2 and the current limiting resistor R37, and finally connected to the isolation optocoupler U30; one port of the isolation optocoupler U30 is grounded, and the other port of the isolation optocoupler U30 is connected with P3.3V voltage; and the X0 is connected to the controller CPUU6, and when a state input signal exists, the controller CPUU6 controls two switching relays of the balanced bridge circuit to simultaneously act on K3 and K4, and the contacts are separated.
The structure that the positive bus-to-ground voltage acquisition loop is connected in parallel to the positive line KM +110 and the ground is as follows: the positive electrode line KM +110 and the ground are respectively connected to a first positive electrode line operational amplifier, and the first operational amplifier is connected to the controller after passing through a linear optical coupler and a second positive electrode line operational amplifier;
the structure that the negative bus voltage-to-ground voltage acquisition loop is connected in parallel to the negative line KM +110 and the ground is as follows: the negative electrode line KM +110 and the ground are respectively connected into a first negative electrode line operational amplifier, and the first operational amplifier is connected into the controller after passing through a linear optical coupler and a second negative electrode line operational amplifier.
The first to fourth balanced resistors R100, R101, R102 and R103 are four power resistors of 15k omega/2W metal film, and the first to fourth unbalanced resistors R110, R111, R112 and R113 are four power resistors of 68k omega/2W metal film.
The controller CPU is a 32-bit ARM series STM32F103 chip, the voltage sampling loop is isolated by a linear optocoupler HCNR201 chip, the state signal input loop is isolated by a TLP521 optocoupler, and the switching relay is HF 41F/24-ZS.
The working process is as follows:
1. when the device normally operates, the two switching relays K3 and K4 do not act, the contacts of the two switching relays are normally closed, the four 15K omega/2W metal film power resistors R100, R101, R102 and R103 form a balance bridge circuit to be switched into a direct current bus, and the voltage acquisition circuit acquires the voltage value of the positive bus to the ground and the voltage value of the negative bus to the ground in real time. Therefore, the single-end grounding condition of the bus can be calculated.
2. When a controller CPU controls a pull-in relay K2, two 68K omega/2W metal film power resistors R110 and R111 are connected to a direct current bus, two voltage measuring circuits detect a positive ground voltage U1 and a negative ground voltage U2 of the direct current bus, then the relay K2 and the power resistors R110 and R111 are disconnected, the pull-in negative terminal switching relay K5 is controlled, two 68K omega/2W metal film power resistors R112 and R113 are put in, two voltage measuring circuits detect a positive ground voltage U3 and a negative ground voltage U4 of the direct current bus, and the double-end grounding condition of the direct current bus is calculated through four voltage values of U1, U2, U3 and U4.
3. When a state signal input circuit formed by connecting a wiring terminal CN3, a transient suppression diode TVS10, a current limiting resistor R42, an anti-reverse diode D2, an isolation optocoupler U30 and a current limiting resistor R37 detects that a signal is input, the control relays K2, K3, K4 and K5 withdraw from four power resistors R100, R101, R102 and R103 of a 15K omega/2W metal film to form a balance bridge and four power resistors R110, R111, R112 and R113 of a 68K omega/2W metal film to form an unbalanced bridge.
Claims (4)
1. A circuit for detecting insulation of a direct current bus is characterized by comprising:
a controller CPU (U6);
the balance bridge circuit is composed of a positive line switching relay (K3), a negative line switching relay (K4) and first to fourth balance resistors (R100, R101, R102 and R103); the first to fourth balance resistors are sequentially connected in series, and then one end of each balance resistor is connected with a normally closed contact of a positive line switching relay (K3), and the other end of each balance resistor is connected with a normally closed contact of a negative line switching relay (K4); the connection point of the second and third balance resistors (R101 and R102) is connected with the Earth (Earth), and the positive line switching relay and the negative line switching relay (K3 and K4) are connected and controlled by a controller CPU (U6): when the device normally operates, the positive line switching relay and the negative line switching relay (K3 and K4) do not act, and the contacts are normally closed;
the unbalanced bridge circuit consists of a positive end switching relay (K2), a negative end switching relay (K5) and first to fourth unbalanced resistors (R110, R111, R112 and R113); after the first unbalanced resistor, the second unbalanced resistor, the third unbalanced resistor and the fourth unbalanced resistor are sequentially connected in series, one end of the first unbalanced resistor, the second unbalanced resistor and the fourth unbalanced resistor is connected with a normally open contact of a positive end switching relay (K2), the negative end of the first unbalanced resistor, the second unbalanced resistor and the third unbalanced resistor (R111 and R112) are connected with the ground, and the positive end switching relay and the negative end switching relay (K2 and K5) are controlled by a CPU (U6); when the device normally operates, the positive end switching relay and the negative end switching relay (K2 and K5) do not act, and the contacts are normally open; when a positive bus unbalanced bridge is put into, the positive side switching relay (K2) acts, and the contact of the relay is closed; when a negative bus unbalanced bridge is put into, the negative end switches on and off a relay (K5) to act, and the contact of the relay is attracted;
a positive bus-to-ground voltage acquisition loop which is connected in parallel to the positive line (KM +110) and the ground;
a negative bus voltage-to-ground voltage acquisition loop which is connected in parallel to the negative line (KM-110) and the ground;
a status signal input circuit: two output ends 1 and 2 of the connecting terminal (CN3) are respectively connected with the cathode of an anti-reflection diode (D2) and a current-limiting resistor (R37) in series after being connected with a transient suppression diode (TVS10) in parallel, and finally connected with an isolation optocoupler (U30); one port of the isolation optocoupler (U30) is grounded, and the other port of the isolation optocoupler (U30) is connected with P3.3V voltage; and the X0 is connected to a controller CPU (U6), and when a state input signal exists, the controller CPU (U6) controls a positive line switching relay and a negative line switching relay (K3 and K4) of the balance bridge circuit to act simultaneously, and contacts of the relays are separated.
2. The circuit for detecting insulation of a direct current bus according to claim 1, wherein:
the structure that the positive bus-to-ground voltage acquisition loop is connected in parallel to the positive line (KM +110) and the ground is as follows: the positive line (KM +110) and the ground are respectively connected to a first positive line operational amplifier, and the first operational amplifier is connected to the controller after passing through the linear optocoupler and the second positive line operational amplifier;
the structure that the negative bus voltage-to-ground voltage acquisition loop is connected into the negative line (KM +110) and the ground in parallel is as follows: the negative electrode line (KM +110) and the ground are respectively connected into a first negative electrode line operational amplifier, and the first operational amplifier is connected into the controller after passing through a linear optical coupler and a second negative electrode line operational amplifier.
3. The circuit for detecting insulation of the direct current bus according to claim 1 or 2, wherein: the first to fourth balanced resistors (R100, R101, R102, R103) are four power resistors of 15k omega/2W metal film, and the first to fourth unbalanced resistors (R110, R111, R112, R113) are four power resistors of 68k omega/2W metal film.
4. The circuit for detecting insulation of a direct current bus according to claim 3, wherein:
the controller CPU is a 32-bit ARM series STM32F103 chip, the positive and negative bus voltage to ground voltage sampling loops are isolated by a linear optocoupler HCNR201 chip, the state signal input loop is isolated by a TLP521 optocoupler, and the switching relay is HF 41F/24-ZS.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920065168.9U CN211263671U (en) | 2019-01-15 | 2019-01-15 | Electric power direct current screen direct current bus insulation detection circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920065168.9U CN211263671U (en) | 2019-01-15 | 2019-01-15 | Electric power direct current screen direct current bus insulation detection circuit |
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| CN211263671U true CN211263671U (en) | 2020-08-14 |
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| CN201920065168.9U Active CN211263671U (en) | 2019-01-15 | 2019-01-15 | Electric power direct current screen direct current bus insulation detection circuit |
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Effective date of registration: 20231025 Address after: 541000 No.28 Huangtong Road, Tieshan Industrial Park, Qixing District, Guilin City, Guangxi Zhuang Autonomous Region Patentee after: Guilin Zhiyuan Power Electronics Co.,Ltd. Address before: Room 02, 17 / F, Baiyun electric science and technology building, Guangzhou private science and Technology Park, 1633 Beitai Road, Baiyun District, Guangzhou City, Guangdong Province, 510540 Patentee before: GUANGZHOU YANGXIN TECHNOLOGY RESEARCH Co.,Ltd. |