JP2641691B2 - Power line verification method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply line verification method capable of searching for a short-circuited portion of a power supply line or a power supply line connected to a specific terminal device.

[0002]

2. Description of the Related Art Conventionally, when searching for a short-circuited portion of a power supply line, a search for a short-circuited portion of the power supply line has been made.
The resistance between the lines is measured. At this time, in order to search for a short-circuit point, an operation of once cutting the resistance measurement point and then measuring the resistance measurement point is sequentially performed at a fixed distance from one end of the power supply line, and such an operation is very troublesome. Therefore, there is a problem that a great deal of labor is required for searching for a short-circuit portion of the power supply line.

On the other hand, when performing indoor wiring work or the like, there are times when it is desired to search for a power supply line connected to a specific terminal device (load) from a plurality of power supply lines. In such a case, the specific terminal device is stopped by sequentially turning off the breakers corresponding to the plurality of power lines, thereby searching for the power line connected to the terminal device. However, shutting off the breaker as described above causes a problem that not only the terminal device concerned, but also other devices connected to the same power supply line are stopped, resulting in a decrease in the operation rate of the terminal device. .

Japanese Patent Application Laid-Open No. 54-85391 discloses that a line current is changed by connecting and disconnecting both ends of a power supply line on a load side through a switch via a test resistor, and the change in the line current is reflected on one side of the power supply line. A method of detecting a line by detecting with a clamp meter clamped to the line is described.

However, according to this configuration, since the load current and the change current appear in the detection clamp meter, the clamp meter needs to have at least a range in which the load current can be detected. Under this condition, if an attempt is made to detect a current change due to the intermittent operation of the switch, the load
_The current change due to the intermittent operation of the switch with respect to ₀ is I _0/10
In 0 the change can not be detected, the change of at least I about _0/10 is required. Therefore, when the load current I ₀ is a large line such as 50 amps or 100 amps, the change current for detection needs to be 5 amps or 10 amps. For example, to obtain a change of 10 amps at 100 volts, There is a disadvantage that a resistor having a large capacity of 1 KW is required.

In some distribution lines, a current close to or exceeding the capacity limit may already be flowing. In this case, if a change current as high as 10% as described above is passed, the breaker may be cut off in some cases. There is. In addition, when the size of the load changes, the magnitude of the change current also needs to be changed.Therefore, it is necessary to replace the inspection resistor with a resistor having an appropriate resistance value according to the load. You need to know if there is, and taking the time to do this can be a tedious task.

Further, since a load current also appears in the clamp meter as described above, it is necessary to prepare a large number of clamp meters having a measurement range corresponding to the size of the load.
This is a very expensive and inefficient operation.

Incidentally, the present invention is disclosed in Japanese Patent Application Laid-Open No. 54-853.
In order to apply the configuration of JP-A-91, a flicker generator, which will be described below, is inserted between one terminal device side and the other breaker side of a pair of lines constituting the same power supply line, and Thus, the pair of lines is clamped by the clamp meter. However, since the present invention seeks to search for a power supply line connected to a specific terminal device in the first place, the line to which the flicker generator should be connected should not be known on the breaker side. is there. If the breaker is blindly connected to any of the lines on the breaker side, there is a high risk of connecting power lines of different systems.

The present invention has been made in view of the above circumstances, and makes it possible to easily search for a short-circuit point of a power supply line, or to cut off a breaker in a power supply line connected to a specific terminal device. It is an object of the present invention to provide a power supply verification method that can search without cost and easily.

[0010]

In order to achieve the above object, the present invention employs the following means . That is, in the power supply line verification method according to the present invention, first, a variable resistor, driving means for driving a movable contact piece of the variable resistor, and a current limiting fixed resistor connected in series to the variable resistor It requires a flicker generator with an instrument .

In searching for a short-circuit point of a power supply line,
Both ends of the flicker generator are interposed in series in one line constituting a power supply line, and by driving a movable contact piece of the variable resistor, the resistance value is periodically increased or decreased,
A flicker current is generated. If this flicker current is detected sequentially from the side of the flicker generator inserted into the line by, for example, a clamp meter toward the load side, the signal will not be detected at the time when the short circuit point is passed, It turns out that the location is a short circuit location.

When searching for a power supply line connected to a specific terminal device, one terminal of the flicker generator is connected to a non-ground line of the power supply line on the terminal device side, and the other terminal is connected to the other terminal. Terminal is grounded. Then, as described above, the movable contact piece is driven to generate a flicker current in the line, and a pair of supply lines are simultaneously clamped by the clamp meter. That is, only the flicker current is canceled by canceling the effect of the load current. and to be able to explore the power line terminal device is connected by detecting at breaker side.

By detecting the flicker current on the breaker side in this way, a power supply line connected to the terminal device is searched.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A power line verification method according to the present invention requires a flicker generator for generating flicker on a power line. FIG. 1 is a diagram showing the principle configuration of the flicker generator.

In FIG. 1, a variable resistor R1 has a movable contact piece 1 driven by a motor M,
The resistance value is configured to be periodically increased and decreased. This variable resistor R1 has a fixed resistor R for limiting current.
2 are connected in series. The value of the fixed resistor R2 is appropriately determined in consideration of the line voltage so that the current flowing through the power supply line to which the flicker generator is connected is about several mA to several A.

A plurality of types of voltages are connected to the power supply line (for example, a voltage of 100 V, 200 V or more).
In some cases, as shown in FIG. 2A, fixed resistors R3, R4, and R5 determined corresponding to respective voltages are connected to a variable resistor R1, and the fixed resistors R, R4, and R5 are connected to each other. Either one may be selected as appropriate by switching the rotary switch SW.

Consider a case where a commercial voltage S1 as shown in FIG. 3A is applied between both terminals T1 and T2 of the flicker generator as shown in FIGS. 1 and 2A. In this case, the resistance value of the fixed resistor R2 (R3, R4, R5) is adjusted, a current is supplied to enable the operation of the clamp meter, and the movable piece 1 of the variable resistor R1 is further driven by the motor M.
Is driven to rotate at most several times per second, the resistance value of the variable resistor R1 periodically increases and decreases as shown in FIG. As a result, the resistances R1 and R2 (R
3, R4, R5) is measured by an AC meter (a clamp meter, which will be described later, is also a type of AC meter). Since the pointer vibrates in response to a change of about / 10 seconds, the indication of the meter appears as a flicker as shown in FIG. 3 (c). This state is called a flicker current in the present invention.

Further, as shown in FIG. 2B, the control voltage of the thyristor SR (or transistor) is obtained from the movable contact of the variable resistor R1 so that the thyristor S
A configuration may be adopted in which a flicker current required for R flows.

FIG. 4 shows a waveform diagram when the configuration shown in FIG. 2B is employed. Considering one cycle of the resistance change (FIG. 4B) of the variable resistor R1 due to the rotation of the motor,
In the initial state where the resistance between the anode and the movable contact piece 1 is zero, even if the voltage shown in FIG. 4A is applied between the anode and the cathode, the voltage between the anode and the gate is zero. The thyristor SR does not conduct. When the resistance between the anode and the movable contact piece 1 is small, a sufficient voltage is not applied between the anode and the gate, so that the anode and the cathode do not conduct. Therefore, as shown in FIG. 4C, when the voltage applied to both ends of the thyristor SR is relatively high, the thyristor SR conducts. When the resistance between the anode and the movable contact piece 1 gradually increases, the voltage between the anode and the gate increases, and the anode and the cathode conduct even if the voltage is low. Therefore, the resistors R1 and R2 (R
When the current flowing through (3, R4, R5) is measured by an AC meter (clamp meter), the indication of the meter becomes flicker-like as shown in FIG. 4 (d), as in the case of FIG. 3 (c).

Next, the case where the above-mentioned flicker generator is used for searching for a short-circuited portion of a power supply line will be described with reference to FIG. As shown in the drawing, one of the lines L1 and L2 constituting the power supply line is removed from the breaker 2, and the above-described flicker generator is inserted in series between them. The fixed resistor R2 (R3, R4, R5) allows a current of about 10 mA to several A to flow through the power supply line with the breaker turned on (the size is set according to the characteristics of a clamp meter described later). Is set. When the movable contact piece 1 of the variable resistor R1 is driven, a flicker current (see FIG. 3C) flows through the lines L1 and L2 as indicated by arrows in FIG. That is, short-circuit point 3
Flicker current flows to the breaker side, but does not flow to the terminal side from the short-circuit point 3.

In this state, if a clamp meter (a type of AC meter) is clamped on the line L1 on the load side of the flicker generator, the flicker current will appear on the clamp meter. The flicker currents are sequentially moved to separated positions, and after passing the short-circuit point 3, the flicker current cannot be detected. As a result, the short-circuit point 3 can be detected.

Next, a case where the above-described flicker generator is used to search for a power supply line connecting to a specific terminal device will be described with reference to FIG. One terminal of the flicker generator is connected to one line L1 of a power supply line with the breaker turned ON on the side of the specific terminal device 4, and the other terminal is grounded. Further, the power supply lines L1 and L2 are simultaneously clamped by a clamp meter. Since the grounding may be performed near the terminal device 4, the setting operation of the flicker generator is extremely easy.

When the movable contact piece 1 of the variable resistor R1 is driven in such a state, the flicker current described with reference to FIG. 3C is generated by using the power supply voltage E as a driving source as shown in FIG. , One end of the power supply → line L1 → resistor R1 → resistor R2
(R3, R4, R5) occurs in a loop returning to the other end of the power supply via the ground. However, since the other end of the flicker generator is grounded as described above, the flicker current does not flow through the other line L2 of the power supply line.

As shown in FIG. 6, one of the low-voltage distribution lines is always grounded on the secondary side of the transformer for security reasons. Here, when the power lines L1 and L2 as shown in FIG. 6 are simultaneously clamped by the clamp meter, the induced currents based on the load current of the commercial frequency are mutually canceled and do not appear in the clamp meter but are superimposed flicker. Since the current flows only through one line L1, a flicker current shown in FIG. 3C appears in the clamp meter.

Therefore, on the breaker side, a specific pair of lines of the plurality of pairs of power lines are simultaneously clamped by the clamp meter, and if a flicker current is detected, the power line is connected to a specific terminal device. It turns out that it is.

Further, in this case, since the flicker current has a very high ground resistance, only a few mA flows, and the variable resistor R1 and the fixed resistor R2 (R3, R3) having a very small capacity.
R4, R5) can be used, and the flicker current range can be adapted to each measurement only by changing the value of the fixed resistance according to the power supply voltage. Therefore, it is not necessary to prepare a clamp meter having a plurality of types of ranges. Absent. Further, since the operation does not significantly affect the load current, the detection operation can be performed without turning off the load (even when the load is on).

[0027]

As described above, according to the present invention, a flicker current is generated in the power supply line by periodically increasing or decreasing the resistance value of the variable resistor connected to the breaker side of the power supply line. Therefore, it is possible to easily search for a short-circuit portion of the power supply line depending on the presence or absence of the flicker current.

Further, according to the present invention, one terminal of the variable resistor is connected to one line on the load side of the power supply line, and the other terminal of the variable resistor is grounded, so that the resistance of the variable resistor is reduced. Since the flicker current is generated in the power supply line by increasing and decreasing periodically, it is sufficient to use a small-capacity resistor regardless of the size of the load, and it is necessary to know the size of the load in advance. Moreover, there is no danger of breaking the circuit breaker since no large current change occurs during the measurement. Therefore, there is an effect that the power supply line can be easily searched at low cost.

[Brief description of the drawings]

FIG. 1 is a principle configuration diagram of a flicker generator used in the present invention.

FIG. 2 is a configuration diagram of another embodiment of the flicker generator used in the present invention.

FIG. 3 is an operation explanatory diagram of the flicker generator shown in FIGS. 1 and 2 (a).

FIG. 4 is a diagram illustrating the operation of the flicker generator shown in FIG. 2 (b).

FIG. 5 is an explanatory diagram in a case of searching for a short-circuit point of a power supply line.

FIG. 6 searches for a power supply line connected to a specific terminal device
FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Movable contact piece 2 Breaker 3 Short-circuit point 4 Terminal equipment M Motor L1, L2 Power supply line R1 Variable resistor R2 (R3, R4, R5) Fixed resistor

Claims (2)

(57) [Claims] 1. A flicker generator comprising a variable resistor, driving means for driving a movable contact piece of the variable resistor, and a current limiting fixed resistor connected in series to the variable resistor. Then, both ends of the flicker generator are interposed in series with one line of a power supply line, and the driving means drives the variable resistor to increase or decrease the resistance value of the variable resistor to generate a flicker current. A power line verification method, wherein a clamp meter clamps a line to which the flicker generator is connected and detects a flicker current to search for a short-circuited portion of the power line. 2. A flicker generator comprising: a variable resistor; driving means for driving a movable contact piece of the variable resistor; and a current limiting fixed resistor connected in series to the variable resistor. One terminal of the flicker generator is connected to a non-ground line of the power supply line on the terminal device side, and the other terminal is grounded, and the variable resistor is driven by the driving means to drive the variable resistor. A flicker current is generated by increasing or decreasing the resistance of the device, a pair of target power lines are clamped simultaneously by a clamp meter, and only the flicker current is detected on the breaker side to search for the power line to which the terminal device is connected. And a power line verification method .