CN210142899U - Selective leakage protection circuit with low-loss signal conditioning - Google Patents
Selective leakage protection circuit with low-loss signal conditioning Download PDFInfo
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- CN210142899U CN210142899U CN201921158587.3U CN201921158587U CN210142899U CN 210142899 U CN210142899 U CN 210142899U CN 201921158587 U CN201921158587 U CN 201921158587U CN 210142899 U CN210142899 U CN 210142899U
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Abstract
The utility model relates to a selective leakage protection circuit that signal low loss was taked care of, including the low modulate circuit that decreases of signal that connects gradually, single-phase electric energy measurement circuit, core processing circuit and execution circuit, zero sequence voltage and zero sequence current obtain differential signal through the low modulate circuit that decreases of signal, single-phase electric energy measurement circuit calculates voltage virtual value, electric current virtual value, power factor, fundamental wave reactive power, core processing circuit obtains zero sequence voltage virtual value, zero sequence current virtual value, power factor, fundamental wave reactive power, judge whether surpass the setting value. The utility model discloses the original analog signal of accurate transmission of the low-loss conditioning circuit of signal, signal information remains intact; the single-phase electric energy metering circuit has high AD sampling precision, improves the resolution ratio of zero-sequence current and zero-sequence voltage signals, and has more sensitive fault identification; the anti-interference capability is stronger, and the device is suitable for being used in a severe environment on site.
Description
The technical field is as follows:
the utility model relates to a coal mine safety technical field especially relates to a selectivity earth leakage protection circuit that is used for low regulation of losing of signal of colliery safety coefficient.
Background art:
the existing selective leakage protection is mainly based on the signal characteristics of zero-sequence voltage and zero-sequence current. The signal characteristics are (1) weak steady-state fault signal, smaller compensated signal, (2) greatly influenced by grounding arc, (3) greatly influenced by arc suppression coil compensation degree, (4) large field interference, small signal-to-noise ratio, and (5) wide signal amplitude range. Due to the complex signal characteristics, the signal conditioning of the existing selective leakage protection circuit often has the following problems: the filtering depth is too deep, useful transient signals are filtered, the filtering depth is too shallow, and the signal-to-noise ratio is small; the linear range of the acquisition circuit is narrow, and the signal is incomplete; the peak overvoltage burns out the sampling port; low AD precision and poor signal resolution.
The utility model has the following contents:
the utility model aims at providing a signal that disturbs for a short time, the signal is strong, the precision is high, signal resolution is strong is hanged down the selectivity earth leakage protection circuit of taking care of.
In order to achieve the above object, the present invention provides a selective leakage protection circuit with low signal loss conditioning, which comprises a low signal loss conditioning circuit, a single-phase electric energy metering circuit, a core processing circuit and an execution circuit;
the signal low-loss conditioning circuit is used for inhibiting high-frequency interference signals of the zero-sequence voltage and zero-sequence current signal input ports;
the single-phase electric energy metering circuit is electrically connected with the signal low-loss conditioning circuit and is used for processing the differential signals in real time, calculating a voltage effective value, a current effective value, a power factor and fundamental wave reactive power and storing the voltage effective value, the current effective value, the power factor and the fundamental wave reactive power into corresponding registers;
the core processing circuit is electrically connected with the single-phase electric energy metering circuit to realize data interaction and is used for filtering and isolating high-frequency interference of the rear-side data bus, isolating high-frequency interference of the front-side data bus, isolating filtering and decoupling of the rear-side power supply and isolating filtering and decoupling of the front-side power supply;
the execution circuit is electrically connected with the core processing circuit and used for outputting signals.
Preferably, the signal low-loss conditioning circuit comprises a current signal low-loss conditioning circuit and a voltage signal low-loss conditioning circuit, and the current signal low-loss conditioning circuit or the voltage signal low-loss conditioning circuit comprises a high-voltage capacitor, a magnetic bead, a bidirectional transient diode, a current transformer, an RC low-pass filter and a filter capacitor which are electrically connected in sequence.
Preferably, the single-phase electric energy metering circuit comprises a single-phase electric energy metering chip, a crystal oscillator starting-up capacitor, a metering chip analog power supply filter capacitor, a metering chip digital power supply filter capacitor and a metering chip in-chip reference filter capacitor, wherein the crystal oscillator starting-up capacitor, the metering chip analog power supply filter capacitor, the metering chip digital power supply filter capacitor and the metering chip in-chip reference filter capacitor are respectively and electrically connected with the single-phase electric energy metering chip.
The single-phase electric energy metering chip adopts CS 5463.
Preferably, the core processing circuit comprises a CPU, an RC filter circuit, a digital isolator and a filtering decoupling capacitor, the CPU is electrically connected to the digital isolator, and an incoming line end and an outgoing line end of the digital isolator are electrically connected to the RC filter circuit and the filtering decoupling capacitor, respectively.
Wherein, the CPU adopts LPC 1768.
Preferably, the execution circuit comprises a CPU, a driving chip, an optocoupler, a relay driving chip, an RC filter circuit and a relay contact arc extinguishing unit, the CPU is electrically connected with the driving chip through the RC filter circuit, the driving chip is electrically connected with the relay driving chip through the optocoupler, and the relay driving chip is electrically connected with the relay contact arc extinguishing unit.
Wherein, the CPU adopts LPC 1768.
The leakage protection method of the selective leakage protection circuit for low-loss signal conditioning comprises the following steps:
firstly, obtaining differential signals by the zero-sequence voltage and the zero-sequence current through a signal low-loss conditioning circuit respectively, and accessing the differential signals into corresponding interfaces of a single-phase electric energy metering circuit respectively;
secondly, the single-phase electric energy metering circuit processes the differential signals in real time, calculates a voltage effective value, a current effective value, a power factor and fundamental wave reactive power respectively, and stores the voltage effective value, the current effective value, the power factor and the fundamental wave reactive power into corresponding registers;
reading a voltage effective value register, a current effective value register, a power factor register and a fundamental wave reactive power register of the single-phase electric energy metering circuit by the core processing circuit through a data bus to obtain a zero sequence voltage effective value, a zero sequence current effective value, a power factor and fundamental wave reactive power, and judging whether the zero sequence voltage effective value, the zero sequence current effective value, the power factor and the fundamental wave reactive power exceed a set value;
and fourthly, the execution circuit outputs an execution signal.
The third step specifically comprises the following steps:
(1) initializing a system;
(2) the CPU reads a zero sequence voltage effective value, a zero sequence current effective value, a power factor and fundamental wave reactive power of the single-phase electric energy metering circuit through a data bus, and calculates a process phase difference;
(3) calculating the phase difference between zero sequence voltage and zero sequence current according to the process phase difference and the fundamental wave reactive power;
(4) judging whether the zero sequence voltage effective value and the zero sequence current effective value exceed set values or not, if not, returning to the step (2), and if so, entering the next step;
(5) and (3) judging whether the zero sequence active power meets the grounding protection principle, if not, returning to the step (2), and if so, outputting an execution signal.
The utility model discloses following positive effect has:
(1) the signal low-loss conditioning circuit accurately transmits the original analog signal, and the signal information is completely reserved;
(2) the single-phase electric energy metering circuit has high AD sampling precision, improves the resolution ratio of zero-sequence current and zero-sequence voltage signals, and has more sensitive fault identification;
(3) the anti-interference capability is stronger, and the device is suitable for being used in a severe environment on site;
(4) the leakage protection method considers the condition that the power grid is compensated by the arc suppression coil, and has wider application range.
Description of the drawings:
fig. 1 is a schematic diagram of a selective leakage protection circuit for low loss conditioning of signals in accordance with the present invention;
fig. 2 is a schematic circuit diagram of a low-loss signal conditioning circuit according to the present invention;
fig. 3 is a schematic circuit diagram of a single-phase electric energy metering circuit of the present invention;
fig. 4 is a circuit schematic diagram of the core processing circuit of the present invention;
FIG. 5 is a schematic diagram of a processing method of the core processing circuit of the present invention;
fig. 6 is a schematic circuit diagram of an execution circuit according to the present invention.
The specific implementation mode is as follows:
the following detailed description of the preferred embodiments of the present invention will be provided in conjunction with the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, and the protection scope of the present invention can be clearly and clearly defined.
As shown in fig. 1, a selective leakage protection circuit for low-loss signal conditioning includes a low-loss signal conditioning circuit, a single-phase power metering circuit, a core processing circuit, and an execution circuit.
The signal low-loss conditioning circuit is used for inhibiting high-frequency interference signals of a zero-sequence voltage and zero-sequence current signal input port, as shown in fig. 2, a zero-sequence voltage signal U0 and a zero-sequence current signal I0 are respectively connected to corresponding channels of the signal low-loss conditioning circuit, a common point of the two signals is connected to an OCOM, the signal low-loss conditioning circuit comprises a current signal low-loss conditioning circuit and a voltage signal low-loss conditioning circuit, and the current signal low-loss conditioning circuit or the voltage signal low-loss conditioning circuit comprises a high-voltage capacitor, a magnetic bead, a bidirectional transient diode, a current transformer, an RC low-pass filter and a filter.
High-voltage capacitors C29, C69 and C12 filter high-voltage interference signals, bidirectional transient diodes D25 and D53 protect zero-sequence voltage and zero-sequence current signal input ports to prevent strong interference signals from damaging internal components, CT1, CT2 are high-precision, low-phase-shift current transformers to isolate external original signals from internal sampling circuits, magnetic beads FB3, FB4, FB1, FB2 inhibit high-frequency interference signals on signal lines, resistors R59, R64, R92, R103 respectively form RC low-pass filters with capacitors C23, C25, C11, C96 to filter high-frequency signals, C60, C97 eliminate differential mode interference in the signals, D27, D28, D9, D11 prevent high voltage from burning chip voltage and current ports, R16, R51, R58, R101 convert original voltage type signals into current type signals to be connected to the input side of the current transformers, r38, R60, R40, R57, R56, and R61 convert the current-type signals output from the current transformers CT1 and CT2 into voltage-type signals, respectively, and output the signals in a differential input mode. The zero sequence voltage and the zero sequence current are respectively processed by a signal low-loss conditioning circuit to obtain differential signals VIN +, VIN-, IIN + and IIN-. VIN +, VIN-, IIN + and IIN-are respectively connected to corresponding interfaces of the single-phase electric energy metering circuit.
The ratio of UO to VIN being constant
The ratio of Io to IIN is constant
The single-phase electric energy metering circuit is electrically connected with the signal low-loss conditioning circuit and used for processing the differential signals in real time, calculating a voltage effective value, a current effective value, a power factor and fundamental wave reactive power and storing the voltage effective value, the current effective value, the power factor and the fundamental wave reactive power into corresponding registers. As shown in fig. 3, the single-phase electric energy metering circuit includes a single-phase electric energy metering chip, a crystal oscillator starting-up capacitor, a metering chip analog power supply filter capacitor, a metering chip digital power supply filter capacitor, and a metering chip in-chip reference filter capacitor, where the crystal oscillator starting-up capacitor, the metering chip analog power supply filter capacitor, the metering chip digital power supply filter capacitor, and the metering chip in-chip reference filter capacitor are respectively electrically connected to the single-phase electric energy metering chip.
C83 and C85 are crystal oscillator starting capacitors, C76 and C77 are metering chip analog power supply filter capacitors, C82 is a metering chip digital power supply filter capacitor, C89 is a metering chip on-chip reference filter capacitor, and the metering chip is grounded in a digital grounding mode, is grounded in a short circuit mode and is grounded in a common mode.
CS5463 processes the differential signals VIN +, VIN-, IIN + and IIN-in real time, respectively calculates the voltage effective value, the current effective value, the power factor and the fundamental wave reactive power, and stores the voltage effective value, the current effective value, the power factor and the fundamental wave reactive power into corresponding registers.
The core processing circuit is electrically connected with the single-phase electric energy metering circuit to realize data interaction and is used for filtering and isolating high-frequency interference of the rear-side data bus, isolating high-frequency interference of the front-side data bus, isolating filtering and decoupling of the rear-side power supply and isolating filtering and decoupling of the front-side power supply. As shown in fig. 4, the core processing circuit includes a CPU, an RC filter circuit, a digital isolator, and a filtering decoupling capacitor, the CPU is electrically connected to the digital isolator, and an incoming line end and an outgoing line end of the digital isolator are electrically connected to the RC filter circuit and the filtering decoupling capacitor, respectively.
An RC filter circuit formed by R15 and C59 is responsible for filtering and isolating high-frequency interference of a rear-side data bus, capacitors C87 and C21 are digital isolators U17 and isolate rear-side power supply filtering and decoupling, R88 is data bus data line pull-up and pull-down resistors, an RC filter circuit formed by R31 and C91 is responsible for filtering and isolating high-frequency interference of a front-side data bus, and capacitors C88 and C95 are digital isolators U17 and isolate rear-side power supply filtering and decoupling.
As shown in fig. 5, the CPU reads the voltage effective value register, the current effective value register, the power factor register, and the fundamental wave reactive power register of CS5463 through the SPI data bus to obtain the zero sequence voltage effective value UrmsZero sequence current effective value IrmsPower factor lambda, fundamental reactive power Q. The zero sequence voltage U is calculated by the following formula0Value of UrZero sequence current IoValue of (A)rAnd a phase difference between the two
UrmsRatio to VIN and IrmsThe ratio to IIN was a constant value of 0.25.
Zero sequence voltage UrIs calculated by the formula
Zero sequence current IrIs calculated by the formula
The CPU reads the power factor register and the fundamental wave reactive power register to obtain the power factor lambda and the fundamental wave reactive power Q, and the phase difference in the process is set as
Phase difference between zero sequence voltage and zero sequence current
Is calculated by the formula
When λ >0
When λ <0
When Q >0
When Q <0
Judging whether the zero sequence voltage effective value and the zero sequence current effective value exceed set values or not, if not, reading the zero sequence voltage effective value, the zero sequence current effective value, the power factor and the fundamental wave reactive power again, if so, judging whether the zero sequence active power meets the grounding protection principle or not, if not, reading the zero sequence voltage effective value, the zero sequence current effective value, the power factor and the fundamental wave reactive power again, and if so, executing circuit action.
The execution circuit is electrically connected with the core processing circuit and used for outputting signals. As shown in fig. 6, the execution circuit includes a CPU, a driving chip, an optocoupler, a relay driving chip, an RC filter circuit, and a relay contact arc extinguishing unit, the CPU is electrically connected to the driving chip through the RC filter circuit, the driving chip is electrically connected to the relay driving chip through the optocoupler, and the relay driving chip is electrically connected to the relay contact arc extinguishing unit.
Q8, R1, D1, R4, C2 prevent that power-on in-process chip U1 from exporting by mistake, R5 prevents high frequency interference with 26 component RC filter circuit, and opto-coupler U18 is signal output isolation, and U23 is relay drive chip, and R7, C7 relay contact arc extinguishing.
The leakage protection method of the selective leakage protection circuit for low-loss signal conditioning comprises the following steps:
firstly, obtaining differential signals by the zero-sequence voltage and the zero-sequence current through a signal low-loss conditioning circuit respectively, and accessing the differential signals into corresponding interfaces of a single-phase electric energy metering circuit respectively;
secondly, the single-phase electric energy metering circuit processes the differential signals in real time, calculates a voltage effective value, a current effective value, a power factor and fundamental wave reactive power respectively, and stores the voltage effective value, the current effective value, the power factor and the fundamental wave reactive power into corresponding registers;
reading a voltage effective value register, a current effective value register, a power factor register and a fundamental wave reactive power register of the single-phase electric energy metering circuit by the core processing circuit through a data bus to obtain a zero sequence voltage effective value, a zero sequence current effective value, a power factor and fundamental wave reactive power, and judging whether the zero sequence voltage effective value, the zero sequence current effective value, the power factor and the fundamental wave reactive power exceed a set value;
and fourthly, the execution circuit outputs an execution signal.
The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention.
Claims (8)
1. A selective leakage protection circuit with low-loss signal conditioning is characterized in that: the system comprises a signal low-loss conditioning circuit, a single-phase electric energy metering circuit, a core processing circuit and an execution circuit;
the signal low-loss conditioning circuit is used for inhibiting high-frequency interference signals of the zero-sequence voltage and zero-sequence current signal input ports;
the single-phase electric energy metering circuit is electrically connected with the signal low-loss conditioning circuit and is used for processing the differential signals in real time, calculating a voltage effective value, a current effective value, a power factor and fundamental wave reactive power and storing the voltage effective value, the current effective value, the power factor and the fundamental wave reactive power into corresponding registers;
the core processing circuit is electrically connected with the single-phase electric energy metering circuit to realize data interaction and is used for filtering and isolating high-frequency interference of the rear-side data bus, isolating high-frequency interference of the front-side data bus, isolating filtering and decoupling of the rear-side power supply and isolating filtering and decoupling of the front-side power supply;
the execution circuit is electrically connected with the core processing circuit and used for outputting signals.
2. The selective leakage protection circuit with low signal loss conditioning according to claim 1, wherein: the signal low-loss conditioning circuit comprises a current signal low-loss conditioning circuit and a voltage signal low-loss conditioning circuit, wherein the current signal low-loss conditioning circuit or the voltage signal low-loss conditioning circuit comprises a high-voltage capacitor, a magnetic bead, a bidirectional transient diode, a current transformer, an RC low-pass filter and a filter capacitor which are sequentially and electrically connected.
3. The selective leakage protection circuit with low signal loss conditioning according to claim 1, wherein: the single-phase electric energy metering circuit comprises a single-phase electric energy metering chip, a crystal oscillator starting-up capacitor, a metering chip analog power supply filter capacitor, a metering chip digital power supply filter capacitor and a metering chip in-chip reference filter capacitor, wherein the crystal oscillator starting-up capacitor, the metering chip analog power supply filter capacitor, the metering chip digital power supply filter capacitor and the metering chip in-chip reference filter capacitor are respectively and electrically connected with the single-phase electric energy metering chip.
4. The selective leakage protection circuit with low signal loss conditioning according to claim 3, wherein: the single-phase electric energy metering chip adopts CS 5463.
5. The selective leakage protection circuit with low signal loss conditioning according to claim 1, wherein: the core processing circuit comprises a CPU, an RC filter circuit, a digital isolator and a filter decoupling capacitor, wherein the CPU is electrically connected with the digital isolator, and the inlet wire end and the outlet wire end of the digital isolator are respectively and electrically connected with the RC filter circuit and the filter decoupling capacitor.
6. The selective leakage protection circuit with low signal loss conditioning according to claim 5, wherein: the CPU adopts LPC 1768.
7. The selective leakage protection circuit with low signal loss conditioning according to claim 1, wherein: the execution circuit comprises a CPU, a driving chip, an optical coupler, a relay driving chip, an RC filter circuit and a relay contact arc extinguishing unit, the CPU is electrically connected with the driving chip through the RC filter circuit, the driving chip is electrically connected with the relay driving chip through the optical coupler, and the relay driving chip is electrically connected with the relay contact arc extinguishing unit.
8. The selective leakage protection circuit with low signal loss conditioning according to claim 7, wherein: the CPU adopts LPC 1768.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110350476A (en) * | 2019-07-23 | 2019-10-18 | 天地（常州）自动化股份有限公司 | The selective earth leakage protection circuit and earth leakage protecting method of the low damage conditioning of signal |
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2019
- 2019-07-23 CN CN201921158587.3U patent/CN210142899U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110350476A (en) * | 2019-07-23 | 2019-10-18 | 天地（常州）自动化股份有限公司 | The selective earth leakage protection circuit and earth leakage protecting method of the low damage conditioning of signal |
| CN110350476B (en) * | 2019-07-23 | 2024-02-09 | 天地（常州）自动化股份有限公司 | Selective leakage protection circuit and leakage protection method for low-loss signal conditioning |
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