CN210604800U - Power grid voltage detection circuit with zero sequence voltage balance adjustment function - Google Patents
Power grid voltage detection circuit with zero sequence voltage balance adjustment function Download PDFInfo
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- CN210604800U CN210604800U CN201921007636.3U CN201921007636U CN210604800U CN 210604800 U CN210604800 U CN 210604800U CN 201921007636 U CN201921007636 U CN 201921007636U CN 210604800 U CN210604800 U CN 210604800U
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Abstract
The utility model discloses a grid voltage detection circuit with zero sequence voltage balance adjustment function, include: the first phase access point, the second phase access point, the third phase access point, the electric wire netting voltage detection circuit who has zero sequence voltage balance adjustment function still includes: the sampling circuit comprises a first sampling circuit, a second sampling circuit and a third sampling circuit; and a zero sequence detection circuit comprising at least one zero sequence capacitor; the primary coil is connected in parallel with the zero sequence capacitor; the detection coil is used for coupling with the primary coil to detect zero sequence voltage; the first sampling circuit, the second sampling circuit and the third sampling circuit are connected to the zero sequence detection circuit; the first sampling circuit, the second sampling circuit and the third sampling circuit respectively comprise a fixed value capacitor, a plurality of adjusting capacitors and adjusting switches connected with the adjusting capacitors in parallel. The utility model discloses an useful part lies in providing a rational in infrastructure and can realize the electric wire netting voltage detection circuit who has zero sequence voltage balance adjustment function that detects simultaneously.
Description
Technical Field
The utility model relates to a voltage detection circuit, concretely relates to electric wire netting voltage detection circuit with zero sequence voltage balance adjustment function.
Background
A large number of metering, monitoring and protecting devices are used in the construction of an intelligent power grid, the voltage of the power grid needs to be collected, a voltage transformer is a common device for collecting the voltage, and in recent years, a capacitance voltage division type electronic transformer is increasingly used for collecting the voltage of a high-voltage power grid due to the advantages of small size, light weight and energy conservation. When a part of protection devices are used in a power grid, phase voltage and zero sequence voltage need to be collected, two groups of independent sampling capacitors need to be configured according to the traditional design scheme, and the design mode doubles the cost and the volume of devices.
The sum of the instantaneous voltages of the three-phase circuit is the zero-sequence voltage. In normal operation, the phase difference of the three-phase voltages is 120 degrees and the amplitude is 1, so that the zero-sequence voltage is basically 0. Therefore, zero sequence voltage detection in the high-voltage power grid is helpful for monitoring the three-phase imbalance condition of the power grid. However, in the actual zero sequence detection line, the detection line itself is unbalanced due to the quality difference of the devices and the problem of equipment.
In order to overcome these problems, a voltage detection circuit needs to be redesigned.
SUMMERY OF THE UTILITY MODEL
A power grid voltage detection circuit with zero sequence voltage balance adjustment function comprises:
a first phase access point for accessing a first phase of an AC power grid;
the second phase access point is used for accessing a second phase of the alternating current power grid;
a third phase access point for accessing a third phase of the ac power grid;
the power grid voltage detection circuit with the zero sequence voltage balance adjustment function further comprises: the sampling circuit comprises a first sampling circuit, a second sampling circuit and a third sampling circuit; and
a zero sequence detection circuit comprising at least one zero sequence capacitor;
the primary coil is connected in parallel with the zero sequence capacitor;
the detection coil is used for coupling with the primary coil to detect zero sequence voltage;
the first sampling circuit, the second sampling circuit and the third sampling circuit are connected to the zero sequence detection circuit;
the first sampling circuit, the second sampling circuit and the third sampling circuit respectively comprise a fixed value capacitor, a plurality of adjusting capacitors and adjusting switches connected with the adjusting capacitors in parallel.
Further, the number of fixed value capacitors in the first sampling circuit, the second sampling circuit, and the third sampling circuit is the same.
Further, the number of the adjustment capacitances in the first sampling circuit, the second sampling circuit, and the third sampling circuit is the same.
Further, the configuration of the adjustment capacitances in the first sampling circuit, the second sampling circuit, and the third sampling circuit is the same.
Further, the number of the turned-on adjustment switches in the first sampling circuit, the second sampling circuit, and the third sampling circuit is different.
Further, the detection coil is connected to a voltage detection device.
The utility model discloses an useful part lies in:
the utility model provides a rational in infrastructure and can realize the electric wire netting voltage detection circuit who detects that has zero sequence voltage balance adjustment function simultaneously.
Drawings
Fig. 1 is a schematic diagram of a preferred embodiment of the present invention.
Detailed Description
As shown in fig. 1, a grid voltage detection circuit 100 with zero-sequence voltage balance adjustment function includes: the first access point A is used for accessing a first phase of an alternating current power grid; the second phase access point B is used for accessing a second phase of the alternating current power grid; and the third phase access point C is used for accessing a third phase of the alternating current power grid. The zero-sequence voltage balance adjustment circuit 100 further includes: a first sampling circuit 11, a second sampling circuit 12, a third sampling circuit 13 and a zero sequence detection circuit; the first sampling circuit 11, the second sampling circuit 12 and the third sampling circuit 13 each include a fixed-value capacitor C1, C2, C3, a plurality of adjusting capacitors C11, C1n, C21, C2n, C31, C3n, and an adjusting switch SW1, SWn connected in parallel with the adjusting capacitors C11, C1n, C21, C2n, C21, C2 n; the adjusting capacitors C1n, C2n and C3n of the first sampling circuit 11, the second sampling circuit 12 and the third sampling circuit 13 which are farthest from the high voltage end are all connected to a connection point D; a zero sequence detection circuit is arranged between the connection point D and the ground, and the zero sequence detection circuit comprises a zero sequence capacitor C4.
In addition, the power grid voltage detection circuit 100 with the zero sequence voltage balance adjustment function further includes: a primary coil L1 and a detection coil L2, wherein the primary coil L1 is connected in parallel with the zero sequence capacitor C4, the detection coil L2 is coupled with the primary coil L1, and the detection coil L2 is connected to a voltage detection device (not shown in the figure)
Thus, the zero sequence voltage can be detected by the detection coil L2.
In addition, specifically, the first sampling circuit 11, the second sampling circuit 12, and the third sampling circuit 13 may include a plurality of fixed capacitors connected in series.
The number of fixed value capacitors in the first sampling circuit 11, the second sampling circuit 12, and the third sampling circuit 13 is the same. The number of adjusting capacitances in the first sampling circuit 11, the second sampling circuit 12, and the third sampling circuit 13 is the same. The configuration of the adjustment capacitances in the first sampling circuit 11, the second sampling circuit 12, and the third sampling circuit 13 is the same. This facilitates mass production.
Specifically, the adjusting capacitors connected in parallel with the closed adjusting switches of the first sampling circuit 11, the second sampling circuit 12 and the third sampling circuit 13 do not work, and otherwise, the adjusting capacitors change the overall capacitance value of the sampling circuits. Thus, some of the adjustment switches in the first sampling circuit 11, the second sampling circuit 12, or the third sampling circuit 13 are turned on, and the other is turned on. When the final debugging is carried out, the adjustment switch can be selected to be conducted according to the configuration condition so as to adjust the capacitance by the short circuit part, thereby realizing the aim of balancing. And closing or opening the adjusting switches in the first sampling circuit, the second sampling circuit or the third sampling circuit according to actual needs to enable the adjusting capacitors to be connected with the constant value capacitors in series to obtain required capacitance values, and adjusting the capacitance values of the first sampling circuit, the second sampling circuit and the third sampling circuit to be equal.
In general, the number of turned-on adjustment switches in the first sampling circuit 11, the second sampling circuit 12, and the third sampling circuit 13 is different.
In order to achieve the purpose of adjustment, capacitance values of a plurality of adjustment capacitors in the first sampling circuit 11, the second sampling circuit 12, or the third sampling circuit 13 may be different, one capacitance value is selected according to a required minimum adjustment amount for the adjustment capacitors, and capacitance values of the remaining capacitors are generally selected according to a multiple of 2, so that corresponding adjustment switches can be selected according to specific conditions to achieve rapid adjustment.
At present, a large amount of capacitive voltage dividers are adopted for sampling voltage on a power grid, the capacitive voltage dividers are also suitable for zero sequence voltage sampling, but the zero sequence voltage is obtained by adding three-phase voltage, so that the sampling value of each phase voltage before addition is required to be accurate, and the capacitance values of capacitors of three phases are required to be strictly equal corresponding to the capacitive voltage dividers. However, the manufacturing process of the capacitor determines that the high-precision capacitor is difficult to manufacture, the precision of the capacitor manufactured by the general industry is +/-5%, the precision requirement of the capacitive voltage divider is within +/-3%, and the manufacturing process is generally controlled to be about +/-1%, so that a large error is brought.
Therefore, by adopting the scheme, the relative error of the capacitance values of the three-phase capacitor is in a specified range, namely, the capacitance values are balanced.
The foregoing illustrates and describes the principles, general features, and advantages of the present invention. It should be understood by those skilled in the art that the above embodiments do not limit the present invention in any way, and all technical solutions obtained by adopting equivalent replacement or equivalent transformation fall within the protection scope of the present invention.
Claims (6)
1. A power grid voltage detection circuit with zero sequence voltage balance adjustment function comprises:
a first phase access point for accessing a first phase of an AC power grid;
the second phase access point is used for accessing a second phase of the alternating current power grid;
a third phase access point for accessing a third phase of the ac power grid;
the method is characterized in that:
the power grid voltage detection circuit with the zero sequence voltage balance adjustment function further comprises: the sampling circuit comprises a first sampling circuit, a second sampling circuit and a third sampling circuit; and
a zero sequence detection circuit comprising at least one zero sequence capacitor;
the primary side coil is connected with the zero sequence capacitor in parallel;
the detection coil is used for coupling with the primary coil to detect zero sequence voltage;
the first sampling circuit, the second sampling circuit and the third sampling circuit are all connected to the zero sequence detection circuit;
the first sampling circuit, the second sampling circuit and the third sampling circuit respectively comprise a fixed value capacitor, a plurality of adjusting capacitors and adjusting switches connected with the adjusting capacitors in parallel.
2. The grid voltage detection circuit with zero sequence voltage balance adjustment function according to claim 1, wherein:
the number of fixed value capacitors in the first sampling circuit, the second sampling circuit and the third sampling circuit is the same.
3. The grid voltage detection circuit with zero sequence voltage balance adjustment function according to claim 1, wherein:
the number of the adjusting capacitors in the first sampling circuit, the second sampling circuit and the third sampling circuit is the same.
4. The grid voltage detection circuit with zero sequence voltage balance adjustment function according to claim 1, wherein:
the configuration of the adjusting capacitors in the first sampling circuit, the second sampling circuit and the third sampling circuit is the same.
5. The grid voltage detection circuit with zero sequence voltage balance adjustment function according to claim 1, wherein:
the number of conducting adjusting switches in the first sampling circuit, the second sampling circuit and the third sampling circuit is different.
6. The grid voltage detection circuit with zero sequence voltage balance adjustment function according to claim 1, wherein:
the detection coil is connected to a voltage detection device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921007636.3U CN210604800U (en) | 2019-07-01 | 2019-07-01 | Power grid voltage detection circuit with zero sequence voltage balance adjustment function |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201921007636.3U CN210604800U (en) | 2019-07-01 | 2019-07-01 | Power grid voltage detection circuit with zero sequence voltage balance adjustment function |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110146751A (en) * | 2019-07-01 | 2019-08-20 | 浙江华采科技有限公司 | Power grid voltage detection circuit with residual voltage balancing function |
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2019
- 2019-07-01 CN CN201921007636.3U patent/CN210604800U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110146751A (en) * | 2019-07-01 | 2019-08-20 | 浙江华采科技有限公司 | Power grid voltage detection circuit with residual voltage balancing function |
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