KR101382470B1 - Line isolation monitoring apparatus - Google Patents

Abstract

The present invention relates to a power line insulation monitoring device. The insulation monitoring device for monitoring the insulation of a power line according to the present invention comprises a power supply part to supply DC voltage for monitoring to the power line; a first resistance part with one or more resistances connected between one side of the power line and the power supply part to have a first resistance value; a second resistance part with one or more resistances of which one end is connected to the other side of the power line to have a second resistance value; and a monitoring part to monitor the poor insulation of the power line by measuring a voltage or a current between the second resistance part and a ground. The power line insulation monitoring device according to the present invention can be simply implemented; be conveniently used; and can accurately carry out insulation monitoring. [Reference numerals] (110) Power supply part; (140) Monitoring part

Description

Power line insulation monitoring apparatus

The present invention relates to a power line insulation monitoring device, and more particularly, to a power line insulation monitoring device that can be simply implemented, easy to use, and can accurately perform insulation monitoring.

Electrical insulation of power lines is one of the most essential components for the operation of electrical equipment and plays an important role in determining the reliability of power lines.

In the case of the conventional case for the insulation monitoring of the two-wire power line, in the first case, induction coils (Co1, Co2) are respectively inserted into each of the two power lines (L1, L2) as shown in FIG. Whether the leakage current is generated or whether the insulation current is generated is determined by determining whether the voltages V1 and V2 induced in the induction coils Co1 and Co2 are the same. In the second case, as shown in FIG. It was determined whether the voltage V induced in the induction coil was generated in the state in which both the power lines L1 and L2 were inserted into one induction coil Co.

In the first case, when a leakage current flows due to poor insulation between one of the two-wire power lines (L1 or L2) and ground, the current or voltage measured at each of the two induction coils Co1 and Co2 is reduced. In the second case, if the current value flowing through each of the two power lines L1 and L2 is the same, the directions of the currents are reversed to each other and are obtained through one induction coil Co. The voltage becomes 0V, and when one of the two power lines L1 and L2 has poor insulation, the voltage induced through one induction coil Co due to the leakage current is a constant value other than 0V. Will appear. Therefore, the state of insulation failure has been identified through the generation of voltage induced in the induction coil (Co).

An example of an insulation monitoring apparatus in the case of three-phase three-wire power lines is Korean Patent Publication No. 10-1037729 (2011.05.23.).

However, these conventional insulation monitoring devices have a problem in that the determination of the insulation state is not accurate because of a complicated circuit and weak noise.

Accordingly, it is an object of the present invention to provide a power line insulation monitoring apparatus capable of overcoming the above conventional problems.

Another object of the present invention is to provide a power line insulation monitoring device that can be simply implemented, can increase the accuracy of insulation monitoring, and is strong against noise.

According to an embodiment of the present invention for achieving some of the above technical problems, an insulation monitoring apparatus for insulation monitoring of a power line according to the present invention, the power supply for supplying a monitoring DC voltage to the power line; A first resistor unit having at least one resistor connected between one side of the power line and the power supply unit to have a first resistance value; A second resistor unit having at least one resistor having one end connected to the other side of the power line to have a second resistance value; And a monitoring unit configured to measure the voltage or current between the second resistor unit and the ground to monitor the insulation failure of the power line.

A one-way conduction element coupled to the power line side may be provided between the power supply unit and the first resistor unit.

The monitoring unit connects a monitoring resistor between the second resistor unit and the ground, measures a voltage across the monitoring resistor, or measures a current flowing through the monitoring resistor, and changes a measured voltage or a measured current. It is possible to monitor the insulation failure of the power line through.

According to another embodiment of the present invention for achieving some of the above technical problem, the insulation monitoring device for the insulation monitoring of the AC three-phase three-wire system power line according to the present invention, the DC voltage for monitoring each of the power line A power supply for supplying power; A first resistor unit connecting a plurality of resistors connected between one side of each of the power lines and the power supply unit to have a first resistance value; A second resistor unit having a plurality of resistors connected to the other sides of the power lines, respectively, to have a second resistance value; And a monitoring unit configured to measure a voltage or current between the second resistor unit and the ground to monitor the insulation failure of each of the power lines.

The resistance value of at least one resistor connected to any one of the power lines may be the same as the resistance value of at least one resistor connected to another power line.

A plurality of one-way conducting elements may be provided between the first resistor unit and the power supply unit, each of which may be forward coupled to the power lines.

The monitoring unit connects a plurality of monitoring resistors to correspond to the respective power lines between the second resistor unit and the ground, measures a voltage across each of the monitoring resistors, or flows through each of the monitoring resistors. The current can be measured, and the insulation failure of each of the power lines can be monitored by changing the measured voltage or the measured current.

When the measured voltage or the measured current is out of a predetermined range, the monitoring unit may determine that the insulation is bad and generate a warning sound or a warning signal.

The monitoring unit may calculate and display the insulation resistance of each of the power lines through the measured voltage or the measured current in real time.

According to the present invention, it is convenient to use through a simple circuit implementation, there is an advantage that can perform the insulation monitoring accurately. In addition, it is possible to display the insulation resistance in real time.

1 and 2 are schematic diagrams of an insulation monitoring apparatus of a conventional two-wire power line.
3 is a schematic circuit diagram of a power line insulation monitoring apparatus according to a first embodiment of the present invention.
4 is a schematic circuit diagram of a power line insulation monitoring apparatus according to a second embodiment of the present invention.
FIG. 5 is a schematic view of a configuration related to one power line in FIGS. 3 and 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings without intending to intend to provide a thorough understanding of the present invention to a person having ordinary skill in the art to which the present invention belongs.

3 is a schematic circuit diagram of a power line insulation monitoring apparatus according to a first embodiment of the present invention.

As shown in FIG. 3, the insulation monitoring apparatus 100 according to the first embodiment of the present invention is to be applied to a two-wire power line, and includes a power supply unit 110, a first resistor unit 120, and a first resistor unit 120. 2 resistor unit 130 and the monitoring unit 140 is provided.

The power supply unit 110 is for supplying a monitoring DC voltage (Vi) to each of the two-wire power lines (L1, L2).

The power supply 110 may be configured to supply, for example, a voltage Vi of DC + 12V, and may supply various levels of DC voltage.

The power lines L1 and L2 are two-wire power lines, and two power lines L1 and L2 are provided.

The first resistor unit 120 is connected between one side of each of the power lines L1 and l2 and the power supply unit 110.

The first resistor unit 120 includes at least one resistor connected to each of the power lines L1 and L2. At least one resistor R11, R12, and R13 having a first resistance value R1 may be connected between the first power line L1 and the power supply unit 110 among the power lines L1 and L2. At least one resistor R11, R12, and R13 having a first resistance value R1 may be connected between the second power line L2 and the power supply unit 110 among the power lines L1 and L2.

That is, resistance values of at least one resistor connected to each of the power lines L1 and L2 may be configured to be the same. In addition, at least one resistor connected to each of the power lines L1 and L2 may be configured such that one resistor has a first resistance value R2 and a plurality of resistors having the same resistance value or different resistance values. The resistors R11, R12, and R13 may be connected in series or in parallel to have the first resistance value R1.

Between the power supply unit 110 and the first resistor unit 120 may be provided with a one-way conductive element (D) forward coupled to the power lines (L1, L2). A diode may be used as the one-way conductive element D and may be connected to each of the power lines L1 and L2.

The second resistor unit 130 is connected between the other side of each of the power lines L1 and l2 and the monitoring unit 140.

The second resistor unit 130 includes at least one resistor having one end connected to each of the power lines L1 and L2. At least one resistor (R21, R22, R23) having a second resistance value (R2) may be connected between the first power line (L1) and the monitoring unit 140 of the power lines (L1, L2), At least one resistor R21, R22, and R23 having a second resistance value R1 may be connected between the second power line L2 and the monitoring unit 140 among the power lines L1 and L2.

That is, resistance values of at least one resistor connected to each of the power lines L1 and L2 may be configured to be the same. In addition, at least one resistor connected to each of the power lines L1 and L2 may be configured such that one resistor has a second resistance value R2, and a plurality of resistors having the same resistance value or different resistance values are provided. The resistors R21, R22, and R23 may be connected in series or in parallel to have the second resistance value R2.

The monitoring unit 140 monitors the insulation failure of the power lines L1 and L2 by measuring the voltage or current between the second resistor unit 130 and the ground G.

In this case, as illustrated in FIG. 5, the monitoring unit 140 may include monitoring resistors Rt connected between the second resistor unit 130 and the ground (G). At least two monitoring resistors Rt may be provided, one may be connected for monitoring the first power line L1, and one may be provided for monitoring the second power line L2.

The monitoring unit 140 measures the voltage across the monitoring resistor (Rt), or by measuring the current flowing through the monitoring resistor (Rt) to determine whether there is a poor insulation of the power lines (L1, L2). . That is, it is possible to monitor the insulation failure of the power lines L1 and L2 through the change of the measured voltage Vo or the measured current measured through the monitoring resistor Rt.

A description of the operation of the monitoring unit 140 will be described with reference to FIG. 5.

4 is a schematic circuit diagram of a power line insulation monitoring apparatus 200 according to a second embodiment of the present invention.

As shown in FIG. 4, the insulation monitoring apparatus 200 according to the second embodiment of the present invention is to be applied to a three-phase three-wire power line, and includes a power supply unit 210 and a first resistor unit 220. , A second resistor unit 230, and a monitoring unit 240.

The power supply unit 210 is for supplying a monitoring DC voltage (Vi) to each of the three-phase three-wire power lines (L1, L2, L3).

The power supply 210 may be configured to supply, for example, a voltage Vi of DC + 12V, and may supply various levels of DC voltage.

The power lines L1, L2, and L3 are three-wire power lines, and three power lines L1, L2, and L3 and a ground line G are provided.

The first resistor unit 220 is connected between one side of each of the power lines L1, l2, and L3 and the power supply unit 210.

The first resistor unit 2120 includes at least one resistor connected to each of the power lines L1, L2, and L3. At least one resistor R11, R12, and R13 having a first resistance value R1 may be connected between the first power line L1 and the power supply unit 210 among the power lines L1, L2, and L3. At least one resistor R11, R12, and R13 having a first resistance value R1 may be connected between the second power line L2 and the power supply unit 210 among the power lines L1 and L2. At least one resistor (R11, R12, R13) having a first resistance value (R1) is formed between the third power line (L3) and the power supply unit 210 of the power lines (L1, L2, L3). Can be connected.

That is, resistance values of at least one resistor connected to each of the power lines L1, L2, and L3 may be configured to be the same. In addition, at least one resistor connected to each of the power lines L1, L2, and L3 may be configured such that one resistor has a first resistance value R2, and has the same resistance value or different resistance values. A plurality of resistors R11, R12, and R13 may be connected in series or in parallel to have the first resistance value R1.

Between the power supply unit 210 and the first resistor unit 220 may be provided with a one-way conductive element (D) forward coupled to the power lines (L1, L2, L3). A diode may be used as the one-way conductive element D, and may be connected to each of the power lines L1, L2, and L3.

The second resistor unit 230 is connected between the other side of each of the power lines L1, l2, and L3 and the monitoring unit 240.

The second resistor unit 230 includes at least one resistor having one end connected to each of the power lines L1, L2, and L3. At least one resistor (R21, R22, R23) having a second resistance value (R2) may be connected between the first power line (L1) and the monitoring unit 240 of the power lines (L1, L2, L3). At least one resistor (R21, R22, R23) having a second resistance value (R1) between the second power line (L2) and the monitoring unit 240 of the power lines (L1, L2, L3). At least one resistor (R21, R22, R23) having a second resistance value (R1) between the third power line (L3) and the monitoring unit 240 of the power lines (L1, L2, L3). ) May be connected.

That is, resistance values of at least one resistor connected to each of the power lines L1 and L2 may be configured to be the same. In addition, at least one resistor connected to each of the power lines L1 and L2 may be configured such that one resistor has a second resistance value R2, and a plurality of resistors having the same resistance value or different resistance values are provided. The resistors R21, R22, and R23 may be connected in series or in parallel to have the second resistance value R2.

The monitoring unit 240 measures the voltage or current between the second resistor unit 230 and the ground (G) to monitor the insulation failure of the power line (L1, L2, L3).

In this case, as illustrated in FIG. 5, the monitoring unit 240 may include monitoring resistors Rt connected between the second resistor unit 230 and the ground (G).

The monitoring resistor (Rt) is provided with at least three, one is connected for the monitoring of the first power line (L1), the other is connected for the monitoring of the second power line (L2), the other one May be connected and provided for the third power line L3.

The monitoring unit 240 measures the voltage across the monitoring resistor (Rt) or by measuring the current flowing through the monitoring resistor (Rt) to determine whether the insulation line of the power supply line (L1, L2, L3). Done. In other words, the insulation line of the power supply line (L1, L2, L3) is monitored by changing the measured voltage (Vo) or the measured current measured through the monitoring resistor (Rt).

A description of the operation of the monitoring unit 240 will be described with reference to FIG. 5.

FIG. 5 is a diagram illustrating a configuration of the insulation monitoring apparatuses 100 and 200 of FIGS. 3 and 4 related to any one of the power lines L of FIGS. 3 and 4 for convenience of description.

Hereinafter, the insulation monitoring operation related to the embodiments of the present invention described with reference to FIGS. 3 and 4 will be described with reference to FIG. 5. In addition, a node at a specific point between the second resistor unit 130 and 230 and the monitoring unit 140 or 240 will be referred to as a first node n1.

As shown in FIG. 5, when one power line L has a wiring structure as shown in FIGS. 3 to 5, when a DC voltage Vi is supplied through the power supply units 110 and 210, a current is generated. Is flowed through the first resistor unit 120 and 220 and the power line L to the second resistor unit 130 and 230. If the insulation resistance is excluded while assuming that the power supply line L is not insulated, the combined resistance value Ro becomes “R1 + R2” and the current at this time is “Vi / (R1 + R2)”. do. When the monitoring resistor Rt is connected, the current becomes "Vi / (R1 + R2 + Rt)".

In addition, since the resistances of the first resistor unit 120 and 220 and the second resistor unit 130 and 230 and the monitoring resistor Rt are connected in series, the current is the same at any point and the voltage is different for each point.

However, since a certain degree of insulation resistance exists, the measurement voltage or current measured through the monitoring units 140 and 240 will have a different value from that in which insulation resistance is excluded.

Here, the insulation resistance Rr should be understood as a concept including capacitive and inductive impedance.

If an insulation defect occurs between the power line L1 and the ground, and the insulation resistance Rr is changed (when an insulation failure occurs, the insulation resistance Rr becomes low), and the insulation resistance Rr Since the second resistor parts 130 and 230 and the monitoring resistor Rt have a parallel connection structure, the composite resistor Ro has a smaller value than the case where the insulation failure does not occur.

For example, assuming that there is no monitoring resistance Rt, the composite resistance Ro is

" "

"

.

That is, when the insulation failure occurs, the synthesis resistance (Ro) is smaller than when the insulation failure does not occur, the measurement current measured by the monitoring unit 140, 240 is increased. In addition, the measured voltage Vo measured through the monitoring resistor Rt is also changed.

 Therefore, the voltage across the monitoring resistor Rt or the voltage between the first node n1 and ground is measured or the current flowing through the monitoring resistor Rt or the voltage between the first node n1 and ground ( Vo) is measured to determine whether insulation is poor.

Various methods can be used to determine the insulation failure.

For example, in a state in which a measurement voltage or a measurement current in a case where an insulation failure does not occur is determined in advance, a measurement voltage Vo or a measurement current measured by the monitoring units 140 and 240 may be out of a predetermined range. The case may be regarded as poor insulation.

Alternatively, since two or three power lines are normally low in case of poor insulation, the measured voltage or the measured current corresponding to one power line corresponds to the other power line. If there is a difference in the measured voltage Vo or the measured current out of the error range, it is possible to determine the insulation failure.

The monitoring unit 140 or 240 may generate a warning sound or a warning signal when it is determined that the power line L is insulated poor. The warning signal may be performed by lighting or blinking an LED of a specific color.

The monitoring units 140 and 240 may calculate and display the insulation resistance Rr of each of the power lines through the measured voltage Vo or the measured current in real time.

The measurement of the insulation resistance Rr is a state in which the resistance values of the first resistance value R1, the second resistance value R2, and the monitoring resistance Rt are known, and thus, the measured voltage or the measured current. It can be calculated mathematically by measuring. If necessary, the current and voltage of the first resistor unit 120 and 220 and the second resistor unit 130 and 230 may be measured and used to calculate the insulation resistance Rr.

Accordingly, the monitoring units 140 and 240 may display the insulation resistance Rr in real time by embedding an algorithm for calculating the insulation resistance Rr.

As described above, according to the present invention, it is convenient to use through a simple circuit implementation, there is an advantage that can perform the insulation monitoring accurately.

The foregoing description of the embodiments is merely illustrative of the present invention with reference to the drawings for a more thorough understanding of the present invention, and thus should not be construed as limiting the present invention. It will be apparent to those skilled in the art that various changes and modifications may be made without departing from the basic principles of the present invention.

110: power supply unit 120: first resistor unit
130: second resistance unit 140: monitoring unit

Claims (9)

Insulation monitoring device for insulation monitoring of power line:
A power supply unit for supplying a monitoring DC voltage to the power line;
A first resistor unit having at least one resistor connected between one side of the power line and the power supply unit to have a first resistance value;
A second resistor unit having at least one resistor having one end connected to the other side of the power line to have a second resistance value;
It is provided with a monitoring unit for monitoring the insulation failure of the power line by measuring the voltage or current between the second resistor and ground,
The monitoring unit connects a monitoring resistor between the second resistor unit and the ground, measures a voltage across the monitoring resistor, or measures a current flowing through the monitoring resistor, and changes a measured voltage or a measured current. Insulation monitoring device, characterized in that for monitoring the insulation failure of the power line through. The method according to claim 1,
Insulation monitoring device, characterized in that between the power supply and the first resistor portion is provided with a one-way conducting element coupled forward to the power line side.
delete Insulation monitoring device for insulation monitoring of AC three-phase three-wire power line:
A power supply for supplying a monitoring DC voltage to each of the power lines;
A first resistor unit connecting a plurality of resistors connected between one side of each of the power lines and the power supply unit to have a first resistance value;
A second resistor unit having a plurality of resistors connected to the other sides of the power lines, respectively, to have a second resistance value;
A monitoring unit for monitoring the insulation failure of each of the power lines by measuring the voltage or current between the second resistor unit and the ground,
The monitoring unit connects a plurality of monitoring resistors to correspond to the respective power lines between the second resistor unit and the ground, measures a voltage across each of the monitoring resistors, or flows through each of the monitoring resistors. Insulation monitoring device, characterized in that for measuring the current, and monitoring the insulation failure of each of the power supply line by changing the measured voltage or the measured current.
The method of claim 4,
Insulation monitoring device, characterized in that the resistance value of at least one resistor connected to any one of the power line is the same as the resistance value of at least one resistor connected to the other power line.
The method of claim 4,
Insulation monitoring device, characterized in that between the first resistor portion and the power supply unit is provided with a plurality of one-way conduction elements each forward coupled to the power lines.
delete The method of claim 4,
The monitoring unit, when the measured voltage or the measured current is out of a predetermined range, the insulation monitoring device, characterized in that it determines that the insulation failure and generates a warning sound or a warning signal.
The method of claim 4,
The monitoring unit, the insulation monitoring device, characterized in that for calculating the insulation resistance of each of the power line through the measured voltage or the measured current to display in real time.

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