JPS5815739B2 - portable current voltage transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a single-phase current to voltage transformer for mobile use.

Conventionally, when a high-voltage distribution line is successfully restarted due to a ground fault, once power transmission is stopped, the insulation at the ground fault point is temporarily restored, making power transmission possible again.

Therefore, ground faults often occur repeatedly,
Exploration of such failures is difficult through external observation and requires a large amount of personnel and exploration time.

Recently, in order to carry out exploration efficiently, a method has been used in which a ground fault direction relay is temporarily installed on a pole to determine the direction of the ground fault point in the event of a recurrence of a fault, and to search while narrowing the fault area. Became.

In this case, due to the operation of the ground fault direction relay installed on the pole,
It is necessary to detect and input the zero-sequence current and zero-sequence voltage of the distribution line that occur at the time of a failure.

Conventionally, the transformers used for this purpose include three split-core single-phase current transformers and three capacitor-divided single-phase voltage transformers.
A total of six machines have been used as one set.

In addition to the above, a transformer that uses an air-core split coil current transformer to extract current output from the secondary coil and extracts voltage output via the capacitance between the primary coil and secondary coil has also been tested. ing.

In this method, current and voltage are simultaneously transformed and input to the ground fault direction relay, but since the distribution line is used as the primary coil, the capacitance between the primary and secondary coils is small. Therefore, the voltage detection ability is also small.

Additionally, if it rains while the transformer is in use, rain water will enter between the split coils of the transformer by climbing up the wires.

Therefore, the inductivity between the primary coil and the secondary coil due to rainwater changes significantly, and the apparent capacitance increases.

Therefore, if the rainwater entering the three transformers does not coincide in time, a problem arises in which the composite vector of the three-phase voltages does not always become zero.

This means that an apparent zero-sequence voltage is detected even if no ground fault occurs.

This may affect the ground fault direction relay and make its operation unstable.

In view of the above, the present invention aims to develop a transformer that has two functions in one unit and can provide stable output even when used in rainy weather.

To explain the present invention with reference to drawings, in FIG. 1, a voltage transformation capacitor γ is provided in series within the handle of a split core current transformer, and one end of the voltage transformation capacitor γ connected in series is , by connecting line 5,
It is connected to the core part 3 of the split core type current transformer, and the other end is connected to the connector 9 to take out the voltage output.

Furthermore, in the split core type current transformer, a conductive contact 2 that is in close contact with the core portion 3 is attached to a gripping portion of the distribution line 1 .

In the present invention having the above configuration, the current output is taken out from the secondary coil 4 of the current transformer, connected to the connector 9 together with the voltage output through the lead wire 8, and taken out to the outside.

Next, the case where the present invention is used in an actual power distribution line will be described.

FIG. 2 shows a state in which the present invention is hooked and attached to the power distribution line 1.

Moreover, FIG. 3 is an explanatory diagram showing the entire case of using the present invention.

That is, the present invention is applied to each phase (a.

b, c), and the current transformer of each phase is
The secondary coil outputs are respectively introduced into the primary coil of the three-phase synthetic transformer 110 and combined, the vector sum is made zero, and the secondary output terminal is connected to the current input terminal of the ground fault direction relay.

Further, the voltage transformation output is obtained from the voltage transformation capacitor γ, the secondary side of the output is star-connected, the three-phase voltage vector sum is always zero, and the neutral point is connected to the voltage dividing capacitor 10. In addition, the other end of the capacitor 10 is grounded, and the voltage output across the capacitor 100 is
Connect it to the voltage input terminal of the ground fault direction relay.

If a ground fault occurs in the distribution line 1 in this state, the zero-sequence current output of the secondary coil of the three-phase composite transformer 110 and the zero-sequence voltage output appearing across the voltage dividing capacitor 100 will be applied to the ground fault direction relay 12. In this case, the ground fault direction relay 12 discriminates the direction of the zero-sequence current and determines the direction of the fault location.

As described above, unlike the fixed-installation type zero-phase current transformer normally used in substations, the present invention has a special structure that is used by directly hooking it to the distribution line, and there is no risk of human contact. Since it is installed at a location, there is no need to ground the iron core 3.

Therefore, a part of the iron core part 3 can be used as part of the electric circuit configuration of the voltage conversion capacitor γ.

In addition, since the voltage transformation capacitor γ is directly connected to the distribution line 1 through the contact 2, a capacitor larger than the capacitance between the primary coil (distribution line) and the secondary coil described above is connected. Since it can be installed by molding inside the handle of the current transformer, there is no change in capacitance due to rainwater infiltration.

Therefore, a stable voltage conversion output can always be obtained.

Note that the voltage transformation capacitor can also be installed as an integral part around the outside of the transformer by applying molded insulation or the like.

In this way, the present invention combines the conventional split core current transformer with
It has two functions as a capacitor type voltage transformer.

Therefore, by using the present invention, the number of transformers used for ground fault fault detection can be reduced to 3, which is half of the conventional number, and the voltage transformation function is stable, so that the number of transformers used for ground fault fault detection can be reduced to 3. It is possible to stabilize the operation.

Furthermore, since the number of transformers can be reduced, the installation and removal work on the pole can be reduced to half of the conventional work, which not only saves labor but also increases the safety of working at heights.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway side sectional view of the present invention, FIG. 2 is an external view showing the installation of the present invention, and FIG. 3 is a diagram illustrating the use of the present invention. 1... Distribution line, 2... Contact, 3...
... Iron core, 4 ... Secondary coil of current transformer, 5 ... Connection wire, γ ... Capacitor for voltage transformation, 8 ...・Leader wire, 9... Connector, 10... Voltage dividing capacitor, 11.
...Three-phase current combining transformer, 12...Ground fault direction relay'.

Claims (1)

[Claims] 1. A portable split core current transformer, a voltage transformation capacitor integrated with the split core current transformer,
The wire gripping portion of the split core current transformer is provided with a conductive contact that is in close contact with the core, and when the split core current transformer is used, the conductive contact, the core, and the voltage transformer are connected to the wire gripping portion of the split core current transformer. A voltage transformer is constructed by an electrical circuit that is introduced into the voltage dividing capacitor through the grounding capacitor, and is grounded.
A portable current-voltage transformer, characterized in that a current output is obtained from the secondary winding of the split core type current transformer.