JP2011091967A - Measuring method and measuring device of contact resistance of switching device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a measuring method of contact resistance of a switching device which is capable of easily and accurately measuring a contact resistance between contact points of a switching part housed in a sealed container while a predetermined sealed state is maintained. <P>SOLUTION: The total resistance is measured which covers from a ground switch ES1 on a bus 1 side to a contact point 4a on the bus 1 side, further extending to a contact switch ES2 on a load 2 side through a contact point 4b of the load 2 side. Meanwhile, a pulse-like voltage is applied between the contact switches ES1 and ES2. A first voltage, a second voltage, and a third voltage are detected which are based on the reflection waves of the voltage reflected on the ground switches ES1, the contact point 4a and 4b, and the ground switch ES2 respectively. The total resistance is distributed at the ratio among the first to third voltages to acquire a contact resistance at the contact points 4a and 4b. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method and apparatus for measuring contact resistance of a switchgear, and is particularly useful when applied to the measurement of contact resistance of a gas insulated switchgear.

  The contact resistance between the contacts of the breaker in a circuit breaker, which is a type of switchgear, is regularly measured from the viewpoint of preventing local overheating at the contact part and finding a construction failure part at the contact part. Here, when the shut-off part is not housed in a closed container or the like, the probe of the measuring instrument can be brought into contact with the shut-off part as the measurement target from the outside, so that a predetermined measurement can be easily performed. .

  On the other hand, among this type of switchgear, there is one in which a shut-off portion is housed in a sealed container filled with an insulating gas such as SF6 gas, and is widely used as, for example, a GIS (gas insulated switchgear). In this way, it is necessary to periodically measure the contact resistance between the contacts of the interrupting part in which the interrupting part is housed in the sealed container. Therefore, such contact resistance is measured through a terminal drawn out of the sealed container. In other words, the GIS circuit breaker is provided with a grounding switch for grounding the bus side and the load side, and the grounding part is grounded to ensure the safety of the operator during maintenance and inspection. When measuring the contact resistance of the interrupting part, the grounding state of the ground switch is released, and each ground switch is used as an external terminal, so that between the ground side switch on the bus side and the load side Measuring resistance. Therefore, in this case, the combined resistance in which the contact resistance of the ground-side switch on the busbar side, the contact resistance of the blocking portion, and the contact resistance on the load side is measured in series. That is, the contact resistance itself of the blocking part cannot be measured. As a result, the measurement of the contact resistance between the contacts of the interrupting part has to be inaccurate. Incidentally, since the resistance of the ground switch portion is relatively large compared to the contact resistance between the contacts of the interrupting portion, this also hinders accurate grasping of the contact resistance between the contacts of the interrupting portion. .

  For example, Patent Literature 1 and Patent Literature 2 exist as publicly known literature relating to the measurement of contact resistance of a contact of a switch.

JP 2009-74829 A JP-A-9-266611

  As described above, in the prior art, the contact resistance itself between the contacts accommodated in the hermetic container such as a GIS blocking part cannot be measured. As a result, there is a problem that the contact point roughness of the interrupting portion cannot be managed over time, and that the contact quality cannot be determined accurately.

  In view of the above prior art, the present invention provides a contact resistance of an opening / closing device that can easily and accurately measure a contact resistance between contacts of an opening / closing portion housed in a sealed container, including GIS, while maintaining a predetermined sealed state. An object of the present invention is to provide a measurement method and a measurement apparatus.

  The first aspect of the present invention that achieves the above object has an opening / closing portion that opens and closes an electric circuit by contacting and separating the contact between the bus side and the load side, and the opening / closing portion is housed in an airtight container together with an insulating medium. And a contact resistance measurement method for a switchgear having a measurement terminal portion taken out of the hermetic container at the bus side and the load side, from the bus side terminal portion to the bus side While measuring the total resistance reaching the load side terminal part through the load side contact, while applying a pulsed voltage between the terminal parts, the voltage is one of the terminal parts, A first voltage, a second voltage, and a third voltage based on reflected waves respectively reflected at the other of the contact portion and the terminal portion are detected, and the total voltage is calculated based on a ratio of the first to third voltages. By dividing the resistance, the contact portion There the determination of the contact resistance measuring method of the contact resistance of the switching device, characterized.

  According to a second aspect of the present invention, in the method for measuring contact resistance of a switchgear described in the first aspect, the switchgear includes a ground switch for grounding on each of the bus side and the load side. It is a switch, and the terminal portion is the ground switch on the bus bar side and the load side.

  The third aspect of the present invention has an opening / closing part that opens and closes an electric circuit by contacting and separating the contact between the bus side and the load side, and the opening / closing part is housed in an airtight container together with an insulating medium, A measuring device for contact resistance of a switchgear having a measurement terminal portion taken out of the sealed container on the bus side and the load side, from the terminal side on the bus side to the contact on the bus side, Further, resistance measuring means for detecting and storing all resistances reaching the load side terminal via the load side contact, pulse voltage generating means for applying a pulsed voltage between the terminals, and the voltage Voltage detecting means for detecting and storing a first voltage, a second voltage, and a third voltage based on reflected waves respectively reflected by one of the terminal portions, the contact portion, and the other of the terminal portions; It is characterized by having In apparatus for measuring contact resistance 閉機 device.

  According to a fourth aspect of the present invention, in the contact resistance measuring device for a switchgear described in the third aspect, the total resistance stored in the resistance measuring means and the voltage detecting means stored in the first resistance. And calculating means for obtaining the contact resistance of the contact portion by dividing the total resistance by the ratio of the first to third voltages based on the first to third voltages, and the contact resistance being the calculation result of the calculating means The contact resistance measuring device of the switchgear further comprises display means for displaying the value of.

  According to the present invention, by applying a pulsed voltage between the terminal part on the bus side and the load side provided outside the sealed container in which the opening / closing part is accommodated, the terminal part on the bus side, the switching part The voltage due to the reflected wave reflected at the contact portion and the load-side terminal portion is detected, and the total resistance from the bus-side terminal portion to the load-side terminal portion through the contact portion of the switching portion is determined by each reflected wave. Since the voltage is apportioned, the contact resistance between the contacts of the opening / closing part can be measured while being housed in the sealed container.

  As a result, not only can the contact resistance of the switchgear alone be detected, but it is also possible to properly manage the aging of the contact portion, etc., and easily perform pass / fail judgment using the contact resistance as a medium. It is possible to conduct detailed inspections efficiently.

It is a circuit diagram showing a gas insulated switchgear (GIS) to which an embodiment of the present invention is applied. It is a circuit diagram which shows the aspect at the time of the measurement of the contact resistance of the contact of the interruption | blocking part of the gas insulated switchgear (GIS) shown in FIG. It is a wave form diagram which shows the voltage based on the reflected wave reflected in each part by application of the pulse-shaped voltage in FIG. FIG. 3 is an equivalent circuit diagram when a pulse voltage is applied to the circuit shown in FIG. 2. It is a block diagram which shows the measuring apparatus of the contact resistance which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a circuit diagram showing a gas insulated switchgear (GIS) to which an embodiment of the present invention is applied. As shown in the figure, the GIS is arranged between the bus 1 and the load 2, and the bus-side disconnector DS1, the circuit breaker CB, and the load-side disconnector DS2 are sequentially connected in series to the bus 1 To the load 2 is formed. Here, the disconnecting devices DS1 and DS2 and the circuit breaker CB are housed in an airtight container together with an insulating gas. In particular, the circuit breaker CB is housed in an airtight container 3 filled with SF6 gas. The load current is supplied or cut off when the bus contacts 4a and 4b are connected to and separated from each other. In addition, the circuit breaker CB is provided with ground switches ES1 and ES2 for grounding the bus side and the load side, respectively. During maintenance and inspection, the ground switches ES1 and ES2 are turned on to ensure the safety of workers. The live parts are grounded.

  In such a GIS, the disconnecting devices DS1 and DS2 and the circuit breaker CB are all turned on in a normal state, and a predetermined load current is supplied from the bus 1 to the load 2. At this time, both the ground switches ES1 and ES2 are left open.

  On the other hand, at the time of maintenance and inspection, the disconnecting devices DS1 and DS2 and the circuit breaker CB are both opened, and then the grounding switches ES1 and ES2 are turned on to ground the charging unit.

  In this embodiment, the contact resistance between the contacts 4a and 4b of the circuit breaker CB is measured in this state. First, the ground state of the ground switches ES1 and ES2 is released. Specifically, the ground lines 5 and 6 connected to the ground switches ES1 and ES2 are removed, and the ground switches ES1 and ES2 are floated from the ground potential. In this state, as shown in FIG. 2, the measuring device I is connected to the ground switches ES1 and ES2, and the circuit breaker CB is turned on. As a result, since a series circuit is formed from the bus-side ground switch ES1 to the bus-side contact 4a and further to the load-side ground switch ES2 via the load-side contact 4b, the total resistance is measured. Such total resistance is a combination of the contact resistances of the ground switches ES1 and ES2 and the contacts 4a and 4b. 2 that are the same as those in FIG. 1 are assigned the same reference numerals, and redundant descriptions are omitted.

After measuring the total resistance as described above, a pulse voltage is applied from the measuring device I between the ground switches ES1 and ES2. By this pulse voltage, reflected waves are returned from the ground switch ES1, the contacts 4a and 4b, and the ground switch ES2 at a predetermined interval. If the voltages of the first wave, the second wave, and the third wave for the first time due to the reflected wave are v ₁ , v ₂ , and v ₃ in this order, the voltages v _{1 to} v ₃ are the ground switch ES1, the contacts 4a and 4b, and the ground. This is due to the voltage reflected by the switch ES2. That is, as shown in FIG. 3, the voltages v _{1 to} v ₃ are set at predetermined intervals (distance from the measuring device I to the ground switch ES1, distance from the ground switch ES1 to the contacts 4a and 4b, and the contacts 4a and 4b. To a ground switch ES2 at intervals corresponding to the distance from the ground switch ES2.

Therefore, it is possible to determine the contact resistance of the contacts 4a, 4b part by apportioning the total resistance ratio of the voltage v ₁ to v _3.

Such a contact resistance measurement principle will be described in further detail. FIG. 4 is an equivalent circuit diagram when a pulse voltage is applied to the circuit shown in FIG. As shown in the figure, the circuit in the present embodiment is configured in each part of the ground switch ES1, the contacts 4a and 4b, and the ground switch ES2 in order from the positive electrode side of the measuring apparatus I (including the pulse voltage generator and the reflected wave detection unit). Impedances Z _ES1 , Z _CB , Z _ES2 are connected in series.

Consider the case where the circuit has only impedance _ZES1 . When a pulse voltage represented by E / s is applied to such a circuit, the voltage V reflected by the impedance _ZES1 portion is represented by the following equation (1).

V (x, s) = (E / s) · {Z ₀ / (Z _s + Z ₀ )} ·
( ^{E- [tau] s} + [rho] (l) ^.e- ( ^{2T- [ tau]) s} ) / (1- [rho] (0). [ ^Rho] (l) ^{.e <-2> Ts} )
... (1)

Here, Z ₀ : Wave impedance (impedance seen from the power source side, this is measured
Since there is no change in the characteristics of the GIS, it becomes a constant. )
Z _s : Impedance of measuring device I
ρ (0): reflection coefficient at the power transmission end (measuring device I),
ρ (0) = (Z _s −Z ₀ ) / (Z _s + Z ₀ )
ρ (l): reflection coefficient at the receiving end (grounding switch ES1),
ρ (l) = (Z _ES1 −Z ₀ ) / (Z _ES1 + Z ₀ )
T: Reflection period
τ: Delay
x: Distance from the power transmission end

Although the denominator of the three items in the above equation (1) represents attenuation due to repeated reflection, in this embodiment, since the first reflected wave is taken out and measured, e ^−2Ts of the denominator of the three items may be ignored. Therefore, when the formula (1) is subjected to inverse Laplace transform, the following formula (2) is obtained.

v (x, t) = E · {Z ₀ / (Z _s + Z ₀ )} ·
{u (t−τ) + ρ (l) · u (t− (2T−τ))} (2)

E · {Z ₀ / (Z _s + Z ₀ )} · ρ (l) · u (t− (2T−τ)) in the above equation (2) is a voltage returned as a reflected wave, and E · {Z ₀ / (Z _s + Z ₀ )} · u (t−τ) is a passing voltage.

  Therefore, the voltage that passes next is calculated as the initial value of the voltage applied to the circuit breaker CB. In the case of the circuit breaker CB, the voltage returned to the measurement point is a value obtained by transmitting the reflected wave from the circuit breaker CB once again through the ground switch ES1. Similarly, the reflected wave at the ground switch ES2 can be obtained.

As a result, the first wave of the measured voltage is the voltage v ₁ , the second wave is the voltage v ₂ , and the third wave is the voltage v ₃ , which correspond to the impedances Z _ES1 , Z _CB , and Z _ES2 , respectively. Here, since the overall resistance is known, the contact resistances of the contact points 4a and 4b can be known by apportioning them.

  FIG. 5 is a block diagram showing an example of a contact resistance measuring apparatus according to an embodiment of the present invention. The measuring device I is connected to ground switches ES1 and ES2 via terminals 18 and 19, respectively. The resistance measuring unit 11 measures the resistance between the ground switches ES1 and ES2 via the changeover switch 12, and stores the measured value. Here, the resistance between the ground switches ES1 and ES2 is the total resistance of the circuit from the ground switch ES1 to the ground switch ES2 via the contacts 4a and 4b of the circuit breaker CB. The pulse voltage generator 14 applies a predetermined voltage pulse between the ground switches ES1 and ES2 via terminals 18 and 19.

The voltage detection unit 15 obtains voltages v ₁ , v ₂ , and v ₃ based on the first reflected wave reflected by each part of the ground switch ES1, the contacts 4a and 4b, and the ground switch ES2 by the pulse voltage applied from the pulse voltage generator 14. Capture and store via the changeover switch 12. That is, the voltage data shown in FIG. 3 is taken in through the terminals 18 and 19 and subjected to predetermined processing to obtain voltages v ₁ , v ₂ , and v ₃ and store the values. Specifically, for example, each acquired voltage value is sampled at a predetermined sampling period, and when the difference from the previous sampling value exceeds a predetermined value, the sampled values are converted to voltages v ₁ , v ₂ , v ₃ , respectively. It is sufficient to store them sequentially.

The calculation unit 16 is based on the total resistance between the terminals 18 and 19 stored in the resistance measurement unit 11 and the voltages v ₁ , v ₂ , and v ₃ stored in the voltage detection unit 15, and the voltages v ₁ , v ₂ , v contacts 4a pro rata the total resistance in a ratio of ₃ to obtain the contact resistance 4b portion, to display the value of the contact resistance on the display unit 17.

Here, control of each part is performed via the control part 13. That is, when measuring the total resistance, the change-over switch 12 connects only between the resistance measuring unit 11 and the terminals 18 and 19, and when applying a pulse voltage, the terminals 18 and 19, the resistance measuring unit 11 and the voltage detecting unit 15 And when the reflected voltages v ₁ , v ₂ , and v ₃ are taken in, control is performed so that only the terminals 18 and 19 and the voltage detector 15 are connected.

According to the present embodiment, it is possible to determine the contact resistance of the contacts 4a, 4b part by apportioning the total resistance between the ground switch ES1, ES2 a ratio of voltages _{v 1, v 2, v 3} . That is, it is possible to detect the contact resistance of the blocking portion in a state where the contacts 4a and 4b are stored in the sealed container 3.

In the embodiment shown in FIG. 5, the calculation unit 16 and the display unit are provided, but these are not necessarily required. When the total resistance is measured, the operator records this, and when the voltages v ₁ , v ₂ , v ₃ are detected by the voltage detection unit 15, the operator records these, and both By associating the information, the operator may obtain a desired contact resistance obtained by dividing the total resistance by the voltages v ₁ , v ₂ , and v ₃ .

  Moreover, although demonstrated using the circuit breaker CB as a switch, it is not restricted to this. The present invention can be similarly applied if the contact portion is a switch accommodated in a sealed container. For example, a disconnector may be used. Moreover, it is not necessary to limit to the apparatus of gas insulation. Even a device filled with insulating oil can be applied in principle.

  INDUSTRIAL APPLICABILITY The present invention can be used in an industrial field where maintenance inspection of a closed type switchgear such as a gas insulated circuit breaker is performed.

I Measuring device 1 Bus 2 Load 3 Sealed container 4a, 4b Contact 5, 6 Ground wire CB Breaker
ES1, ES2 Ground switch 11 Resistance measurement unit 14 Pulse voltage generator 15 Voltage detection unit 16 Calculation unit 17 Display unit

Claims (4)

It has an opening / closing part that opens and closes the electric circuit by contacting and separating the contact between the bus side and the load side, and the opening / closing part is housed in an airtight container together with an insulating medium, and the bus side and the load side A method for measuring the contact resistance of an opening / closing device having a measurement terminal portion taken out of the sealed container,
While measuring the total resistance from the terminal part on the bus side to the contact point on the bus side, and further to the terminal part on the load side through the contact on the load side,
A pulsed voltage is applied between the terminal portions, and the first voltage, the second voltage, and the second voltage based on the reflected waves reflected at one of the terminal portions, the contact portion, and the other of the terminal portions, respectively. Detecting each of the third voltages,
A method for measuring contact resistance of a switchgear, wherein the contact resistance of the contact portion is determined by dividing the total resistance by a ratio of the first to third voltages. In the measuring method of the contact resistance of the switchgear according to claim 1,
The switchgear is a gas insulated switch having a grounding switch for grounding on the bus side and the load side,
The method of measuring contact resistance of a switchgear, wherein the terminal portion is the ground switch on the bus side and the load side. It has an opening / closing part that opens and closes the electric circuit by contacting and separating the contact between the bus side and the load side, and the opening / closing part is housed in an airtight container together with an insulating medium, and the bus side and the load side A device for measuring contact resistance of an opening / closing device having a terminal portion for measurement taken out of the sealed container,
Resistance measuring means for detecting and storing all the resistance from the bus-side terminal portion to the bus-side contact, and further to the load-side terminal portion via the load-side contact;
Pulse voltage generating means for applying a pulsed voltage between the terminal portions;
Voltage detection for detecting and storing the first voltage, the second voltage, and the third voltage based on the reflected waves respectively reflected by the one of the terminal portions, the contact portion, and the other of the terminal portions. And a contact resistance measuring device of the switchgear. In the measuring device of the contact resistance of the switchgear according to claim 3,
Based on the total resistance stored in the resistance measuring means and the first to third voltages stored in the voltage detecting means, the total resistance is divided by the ratio of the first to third voltages. And a display means for displaying the value of the contact resistance, which is a calculation result of the calculation means, and a contact resistance measuring device for a switchgear.

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