JPH0261791B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a device for detecting and displaying deterioration of lightning protection means such as lightning arresters installed for the purpose of protecting power distribution lines, power distribution equipment, etc. To be more specific, it remains inoperable against shock discharge currents caused by lightning, etc., but when the ground leakage current value of a lightning arrester, etc. continuously reaches a predetermined level, this leakage current is detected. The present invention relates to a deterioration display device that provides a simple display that is clearly and reliably visible on inspection.

Prior Art As power distribution networks become larger and more complex,
For the purpose of protecting lines and equipment from lightning surges, etc.
Alternatively, a huge number of lightning arresters are installed for insulation coordination. After an excessive discharge current flows due to a lightning surge or the like, or when moisture intrudes into the interior of the arrester, the arrester deteriorates, and a considerable amount of leakage current to the ground occurs in the deteriorated arrester. If such a deteriorated lightning arrester is left unattended, it may lead to accidents such as ground faults, and the ground fault relays at substations may detect faults in response to this leakage current, leading to power outages.

Therefore, in order to solve the above-mentioned problem, a deterioration indicator that is connected in series between an electric protection means such as a lightning arrester and the earth and gives a simple deterioration indication in response to only the continuously flowing earth leakage current. Although such devices have been proposed, their shear cutting ability has been limited. Therefore, when this deterioration display device is connected in series between the lightning arrester elements arranged for each phase and the ground, the lightning arrester elements for two phases deteriorate simultaneously, and also on the load side of the power line. When a multiple ground fault occurs, and if for some reason a phase shift short circuit occurs through this deteriorated arrester element, the large fault current that flows will no longer be able to be cut off, and the substation will be connected by arc until it trips. be done. As a result, there was a risk that the lightning arrester elements would be thermally destroyed, resulting in a public disaster.

Purpose The purpose of the present invention is to connect a current limiting fuse with a current limiting effect in series to a deterioration indicator, and further provide a discharge gap in parallel to the current limiting fuse, thereby reducing the number of failures that occur in rare cases such as those mentioned above. It is an object of the present invention to provide a deterioration display device with a function of interrupting lightning protection means for interrupting current.

Embodiment Hereinafter, an embodiment embodying the present invention will be described in the first to
This will be explained according to Figure 3.

Reference numeral 1 denotes a lightning arrester element connected in series with this deterioration display device, which is illustrated as a general lightning arresting means. 2 is a transparent synthetic resin insulating outer cylinder of the deterioration indicator; 3 is a synthetic resin cap fitted onto one end of the insulating outer cylinder 2; the cap is fixed with adhesive; The end is a diameter-reduced insertion part 3a
is formed with an opening. Reference numeral 4 denotes a rod-shaped counter electrode that is inserted through the insertion portion 3a of the cap 3 into one end of the insulating outer cylinder 2 along the axis.
A synthetic resin retaining pin 5 whose both ends are locked and fixed to the cat 3 in the radial direction is passed through the pin 5 at a position corresponding to the cap 3, and its outer end is connected to a ground wire (not shown).

The retaining pin 5 is designed to lock the counter electrode 4 to the cap 3 and prevent it from coming out from the insulating outer cylinder 2 during normal handling.
When a predetermined or more outward force is applied to the inner end of the electrode, the counter electrode is formed so as to protrude outward from the insulating outer cylinder 2 and the cap 3 and be separated from the electrode.
The diameter of the pin 5 may be reduced as appropriate to facilitate precipitation at the boundary between the counter electrode 4 and the cap 3. Reference numeral 6 denotes a mounting bolt for mounting a deterioration display device provided at the outer end of the counter electrode 4.

Note that a seal is applied between the counter electrode 4 and the insertion portion 3a of the cap 3 using a sealant 7 for waterproofing (for example, manufactured by Shin-Etsu Chemical Co., Ltd., trade name "Silicon Sealant").

Reference numeral 8 denotes a sealing plug fixed to close the other end of the insulating outer cylinder, and 9 connects the insulating outer cylinder 2 through the sealing plug 8.
A counter electrode inserted along the axial direction of the
A metal retaining pin 10 whose both ends are inserted into and locked in the sealing plug 8 in the radial direction of the central portion is fixed to the sealing plug 8 by passing through it, and the lightning arrester element 1 is connected to the outer end. ing. 11 is insulating tube 2
The outer end of the counter electrode 9 is inserted through the insertion portion 11a, which is a cap fitted onto the other end and fixed with adhesive, and has a reduced diameter at the outer end. It stands out. A protective cover 12 is detachably attached to the outer end of the cap 11 so as to cover the outer end of the counter electrode 9. Note that the same sealant 7 as described above is applied to the portion where the counter electrode 9 and the cap are inserted.

Reference numeral 13 denotes an insulating spacer that is slidably fitted over the entire inner end of the counter electrode 4 on the ground side, and is formed into a cylindrical shape, and on its outer periphery there is a cylindrical discharge spacer with one end closed. An electrode 14 is fitted onto the outside. The outer peripheral surface of the discharge electrode 14 is colored in a color that indicates the normal state of the lightning arrester element 1, for example, yellow. Reference numeral 15 denotes a discharge gap provided between the opposing electrode 4 and the distal end of the discharge electrode 14, and is arranged in parallel with a resistor 16, which will be described later.

16 is a heat generating resistor connected between the inner end of the counter electrode 4 and the closed part 14a of the discharge electrode 14,
The connecting portions 16a and 16b are attached so that when the counter electrode 4 receives a force outward from the axis, one of the connecting portions 16a and 16b is separated. In addition to ordinary electrical resistance like this heating resistor, P.
A TC (positive polarity thermistor) may also be used.

Reference numeral 17 is an ignition agent filled in a space surrounded by the inner end of the counter electrode 4, the spacer 13, and the closed portion 14a of the discharge electrode 14 so as to cover the resistor 16, and the ignition agent The counter electrode 4
is pressed to break the retaining pin 5 and release the lock, and the counter electrode 4 is moved to project outward from the axis and separated from the insulating outer cylinder 2.
The ignition agent 17 is selected to have a property of exhibiting a different color, for example black, from the outer surface of the discharge electrode 14 and the outer surface of the discharge electrode 24 of the current limiting fuse 18, which will be described later, when ignited. Furthermore, this igniter 17
The ignition temperature of resistor 16 and the heat generation characteristics of resistor 16 are
6 is selected so that ignition occurs when a continuous current of a certain level (for example, about 100 mA), that is, alternating current or direct current, flows through the capacitor 6.

The counter electrode 4, the discharge electrode 14, the discharge gap 15, the resistor 16, and the pyrotechnic agent 17 form the display circuit A.
is configured.

18 is the outer end of the closed part of the discharge electrode 14 and the counter electrode 9
It is a current limiting fuse to which a cap-shaped intermediate electrode 19 and a lightning arrester side electrode 20 are respectively connected and fixed to the inner end, and both electrodes 19 are contained in an insulating tube 21 having both electrodes 19 and 20 externally fitted and fixed at both ends. , 20 are disposed and filled with arc-extinguishing sand 23. 24 is a discharge electrode whose one end is connected to the intermediate electrode 19,
It is formed into a cylindrical shape so as to almost cover the current limiting fuse 18, and its outer peripheral surface is colored to indicate the normal state of the arrester element 1, for example, yellow, and the other end is connected to the arrester side electrode 20 and the absorber gear. They extend to face each other with a discharge gap 25 in between. That is, the discharge gap 25 is provided in parallel to the current limiting fuse 18. Note that 26 is a cylindrical insulating spacer interposed between the discharge electrode 24 and the insulating cylinder 21 of the current limiting fuse 18.

This current limiting fuse 18 is such that when a continuous fault current (e.g. 4KV, 4000A) flows through the deterioration display device, the fuse element 22 melts in advance of the discharge gap 25 before the substation trips. chosen to be cut off. Furthermore, when a large impulse current enters the deterioration display device, the fuse does not blow and the current is discharged to the ground via the discharge gap 15 and the discharge gap 25.

Now, the operation of the deterioration display device having the above configuration will be explained.

When the lightning arrester 1 has not deteriorated and its ground leakage current is below a predetermined level, the discharge electrodes 14 and 24 turn yellow through the insulating outer cylinder 2, and the arrester element 1
Displays the normal status of.

When a shock wave due to lightning or the like enters the arrester element 1 in this state, the terminal voltage of the discharge gaps 15 and 25 rises rapidly, causing a flashover between the discharge gaps 15 and 25 and discharging current from the arrester element 1 and the discharge gap 1.
It flows to the earth via 5 and 25. At this time, since the resistor 16 and the pyrotechnic agent 17 are configured to act thermally as described above, the discharge gap 1
For a short time until the sparks collide at points 5 and 25, the ignition agent 17 remains unignited. In addition, since the terminal voltage of the resistor 16 is kept low after the flashover, the ignition agent 1
7 remains unfired as well. In this way, when the surge arrester element 1 does not deteriorate, the deterioration display device having the above structure continues to display the normal state of the surge arrester element 1 both when the surge arrester 1 is in operation and when it is not in operation.

Then, due to several discharges of the arrester element 1,
Alternatively, when the continuous ground leakage current of the lightning arrester element 1 reaches a predetermined level due to aged deterioration or the like, the ignition agent 17 is ignited by the Joule heat generated in the resistor 16. The counter electrode 4 is pressed due to the sudden pressure increase caused by the ignition of the pyrotechnic agent 17, and as a result, the retaining pin 5 is broken and the locking with the cap 3 is released, and the counter electrode 4 is moved from the insulating outer cylinder 2
are separated by a protruding operation, and the separated state can be visually recognized from the outside. Furthermore, when the pyrotechnic agent 17 is ignited, the pressure inside the discharge electrode 14 increases, which flows through the opening into the insulating outer cylinder 2 as a black jet stream, and the fine combustion products flow into the inner surface of the insulating outer cylinder 2 and the discharge. It adheres to the outer surfaces of the electrodes 14,24. As a result, the external appearance of the insulating outer cylinder 2 appears black, indicating the deterioration state of the arrester element 1.

In this way, the display device can confirm the deterioration of the arrester element 1 by double displaying the state in which one counter electrode 4 is separated from the insulating outer cylinder 2 and the appearance of the insulating outer cylinder 2 being black. The visibility effect will be high.

Note that if PTC is used as the resistor 16, the resistance value of the display device during normal state display can be kept low.

In addition, the surge arrester elements 1 for two phases deteriorate at the same time, causing a multiple ground fault on the load side of the power line, and furthermore, if a phase shift short circuit occurs via this arrester element 1, the faulty large current that flows will flow through the substation. Before the current-limiting fuse 18 trips, the fuse element 22 of the current-limiting fuse 18 is blown out before the discharge gap 25.
Therefore, the deteriorated lightning arrester element 1 and the ground wire will not be connected by an arc, and the lightning arrester element 1, the deterioration display device, etc., will not be thermally destroyed by the arc and cause a public disaster.

Furthermore, since a discharge gap 25 is provided in parallel with the current-limiting fuse 18 so that the impulse current is bypassed through the same discharge gap 25, there is no need to use a large-sized current-limiting fuse. It is possible to make it compact in practical use as an attached deterioration indicator.

Effects As detailed above, the present invention provides an indicator circuit that is connected in series to a surge arrester element and grounded, and operates to separate when a continuous leakage current of a predetermined level flows from the surge arrester element to display deterioration. However, by configuring current limiting fuses with parallel discharge gaps connected in series, the arrester elements for two phases deteriorate at the same time, and multiple ground faults occur on the load side, resulting in the deterioration of the deteriorated arrester. Even if a phase shift short circuit occurs through the substation, the faulty large current is cut off before the substation trips, so there is no power outage.
In addition, it prevents thermal destruction of lightning arrester elements and the like from arcing, and has excellent effects without causing a public disaster, making it an excellent invention for industrial use.

[Brief explanation of drawings]

FIG. 1 is a basic circuit configuration diagram of a deterioration display device of the present invention, FIG. 2 is a longitudinal sectional view of the deterioration display device, and FIG. 3 is a sectional view of essential parts showing the operating state after deterioration display. DESCRIPTION OF SYMBOLS 1... Lightning arrester element, 2... Insulating outer cylinder, 4... Counter electrode, 5... Retaining pin, 9... Counter electrode, 14... Discharge electrode, 15... Discharge gap,
16...Resistor, 17...Ignition agent, 18...Current limiting fuse, 19...Intermediate electrode, 20...Surge arrester side electrode, 24...Discharge electrode, 25...Discharge gap.

Claims (1)

[Claims] 1. A current limiting system in which a discharge gap is installed in parallel to a display circuit that is connected in series to the arrester element and grounded, and operates to separate and indicate deterioration when a continuous leakage current of a predetermined level flows from the arrester element. 1. A deterioration indicating device with a lightning break function for a lightning protection means, characterized in that it is configured by connecting fuses in series.