JP2017158341A - Calculation method for operable time count corresponding amount of changeover switch, and calculation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a calculation method for an operable time count corresponding amount of a changeover switch that is more responsive to an actual state, and a calculation system.SOLUTION: The present invention relates to a calculation method for an operable time count corresponding amount of a changeover switch 4 in a load-time tap switching device 3. The calculation method calculates the operable time count corresponding amount by subtracting a number obtained by adding 1 that is the number of times of mechanical deterioration and a number corresponding to the number of times of mechanical deterioration caused by electrical deterioration, each time switching is performed, from a mechanically operable time count that is an operable time count in the case where operation cycle switching is repeated while performing start and stop in every one-tap switching under a non-voltage state.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a calculation method and a calculation system for an amount corresponding to the operable number of times of a switching switch.

In an electric power company, when supplying electricity to a customer, a high voltage is converted into a predetermined voltage by a transformer installed in a substation. In such a state, when the power demand by the customer increases, for example, during the daytime, the voltage falls below the specified value. Conversely, when the customer's power demand decreases, such as at night, the voltage rises above the specified value.
In order to cope with such a case, the transformer is provided with a load tap switching device, the tap is switched by the load tap switching device, and the voltage is adjusted so that the voltage is within a specified range (for example, Patent Document 1).

This on-load tap switching device includes a switching switch that performs a switching operation. However, since the arc contact that opens and closes the load current is worn, the switching switch needs to be replaced after switching a predetermined number of times.
This replacement time directly depends on the wear amount of the arc contact, but it is difficult to confirm the structural wear amount. For this reason, the number of operations of the switching switch is counted, and the switching switch is replaced when the predetermined number of times is reached.
There are two types of possible operation times (lifetime) until replacement of the switching switch, for example, 800,000 times as the number of possible mechanical operations and 200,000 times and 100,000 times as the possible number of electrical operations.

JP 2011-55599 A

  However, the number of times that the electrical operation can be performed is the number of operations that can be performed under the rated step voltage and the rated passing current. Usually, the switching switch is used at a current lower than the rated current. For this reason, the switching switch is often usable even when the number of possible electrical operations exceeds 200 (or 100,000) times, and in fact it can be replaced even though it is still usable. Has been.

  An object of the present invention is to provide a calculation method and a calculation system for an amount corresponding to the operable number of times of the switchgear according to the actual state.

(1) The present invention is a method for calculating the amount corresponding to the operable number of times of the switching switch in the on-load tap switching device, when the operation cycle switching is repeated while starting and stopping at each tap switching in a no-voltage state. By subtracting a number obtained by adding 1 which is the number of times of mechanical deterioration and a number corresponding to the number of times of mechanical deterioration due to electrical deterioration, from the number of times that the mechanical operation is possible. This is a calculation method for calculating the amount corresponding to the operable number of times.

(2) The number corresponding to the number of mechanical deteriorations due to the electrical deterioration may be obtained in consideration of the ratio of the load current at the time of switching to the rated current.

(3) NIm, which is a number corresponding to the number of mechanical degradations due to the electrical degradation, is Im when the load current at the m-th switching is Im and the rated current is In,
The following formula NIm = (Im ² / 200000In ² ) × 600000
Or
NIm = (Im ² / 100,000 In ² ) × 700000
You may obtain | require by either formula of.

(4) NIm, which is a number corresponding to the number of mechanical degradations due to the electrical degradation, is Im when the load current at the m-th switching and Im is the rated current.
The following formula: NIm = (Im / 200000In) × 600000
Or
NIm = (Im / 100,000In) × 700000
You may obtain | require by either formula of.

(5) The present invention is an arithmetic system equivalent to the operable number of times of the switching switch in the on-load tap switching device, and when the operation cycle switching is repeated while starting and stopping at every tap switching in a no-voltage state. By subtracting a number obtained by adding 1 which is the number of times of mechanical deterioration and a number corresponding to the number of times of mechanical deterioration due to electrical deterioration, from the number of times that the mechanical operation is possible. The calculation system includes a calculation unit that calculates an equivalent number of operable times.

(6) You may provide the display part which displays the said operation | movement possible number equivalent amount.

  According to the present invention, it is possible to provide a calculation method and a calculation system for an amount corresponding to the operable number of times of the switchgear according to the actual state.

It is a figure which shows the voltage adjustment system containing the operation frequency equivalent amount calculation system of the switching switch of this embodiment. It is a graph which shows the relationship between the frequency | count of operation | movement of a switching switch and load current in 1st Embodiment. It is a graph which shows the relationship between the frequency | count of operation | movement of a switching switch and load current in 2nd Embodiment.

FIG. 1 is a diagram showing a voltage adjustment system 2 including an operation number equivalent amount calculation system 1 of the switching switch 4 in the on-load tap switching device 3 of the present embodiment.
The voltage regulation system 2 is installed in a distribution substation, and includes a load tap switching device 3 including a switching switch 4, a 90 relay (voltage regulation relay) 5, and an operable number equivalent calculation system. 1.

The on-load tap switching device 3 includes a plurality of taps (not shown) for switching the voltage on the primary side or the secondary side without stopping the supply of electricity. The on-load tap switching device 3 changes the secondary voltage by switching the taps.
That is, the on-load tap switching device 3 has a switching switch 4 so that the output voltage from the secondary side is an appropriate voltage, for example, a standard voltage (101 ± 6 V) stipulated by law or near this standard voltage. The tap is switched under the control of and the output voltage from the secondary side is adjusted.

  The switching switch 4 is provided in the on-load tap switching device 3. The switching switch 4 switches the tap of the on-load tap switching device 3 according to the switching signal sent from the 90 relay 5 and adjusts the secondary-side transmission voltage to be appropriate.

The 90 relay 5 monitors the input voltage on the primary side, and outputs a tap switching command to the switching switch 4 when the voltage is out of a predetermined dead band range.
In the present embodiment, the 90 relay 5 measures not only the input voltage on the primary side but also the current value Im on the primary side. Note that the switching switch 4 operates T seconds after the tap switching operation signal from the 90 relay 5 is generated. For this reason, the 90 relay 5 measures the current value Im flowing from the primary side T seconds after the operation signal transmission.

(Operating frequency equivalent amount calculation system)
The operable number equivalent calculation system 1 includes a calculation unit 11 and a display unit 12.
The calculation unit 11 calculates an amount corresponding to the operable number of times of the switching switch 4 using the current value Im measured by the 90 relay 5.

The operable number equivalent amount is an amount corresponding to the remaining number of switching operations after the calculated time point at which the switching switch 4 can operate. The amount corresponding to the operable number of times is a numerical value larger than the actual number of times that the switching switch 4 can operate, and is the number of times when converted into the number of possible mechanical operations described later.
When the current value Im is constant, the amount corresponding to the operable number can be converted into the actual operable number.

The display unit 12 displays the number of times the switching switch 4 has been switched and the amount of operable times calculated by the calculation unit 11.
The operator periodically observes the display unit 12 and replaces the switching switch 4 when the displayed equivalent amount of possible operations becomes close to zero.

  Next, calculation of the operable number equivalent amount performed by the calculation unit 11 of the operable number equivalent amount calculation system 1 will be described.

  Since the arc contact wears when the load current is switched, the switching switch 4 needs to be replaced when the wear amount exceeds a specified value. However, it is difficult to confirm the amount of wear due to the structure. For this reason, the concept of the number of mechanical operations and the number of electrical operations based on the number of operations is introduced.

The number of times that the mechanical operation is possible is the number of times that the operation can be performed when the operation cycle switching is repeated while starting and stopping each time one tap is switched in a no-voltage state.
The number of electrical operations that can be performed is the number of operations that can be performed when the electrical circuit is opened and closed by the number of times corresponding to a predetermined electrical durability switching under the rated step voltage and the rated passing current.
That is, the number of possible mechanical operations is the number of possible operations when switched without load, and the number of possible electrical operations is the number of possible operations when switched at the rated current.

For example, the switching switch 4 can be mechanically operated 800,000 times, and the electrical operation can be performed 200,000 (or 100,000) times. Therefore, the switchgear 4 is conventionally replaced with 20 (or 100,000) times that can be electrically operated.
However, the number of times that the electrical operation can be performed is an amount corresponding to the number of operations that can be performed when the rated current flows. Actually, since a current value equal to or lower than the rated current is used, the number of times that the switching switch 4 can actually be used is more than 200 (or 100,000) times.

(First embodiment)
The mechanically operable number of times Lm is obtained by the following formula as an approximation.

Lm = Nm + I0 ² × R × t0 × Nm (1)

here,
I0: Switching current of the tap switching device when loaded (0A)
R: Resistance t0: Arc time (arc time 0 seconds)
Nm: Number of mechanical operations (800000)
Therefore, if these are substituted into the equation (1),

Lm = 800000 + 0 ² × R × 0 × 800000

That is,

Lm = 800000 ... (1) '

It becomes.

The electric operation possible frequency Le is obtained by the following formula as an approximation.

Le = Nn + In ² × R × tn × Nn (2)

here,
In: Rated current of tap changer at load R: Resistance tn: Arc time (arc time at rated current)
Nn: Number of electrical operations (200000 or 100,000)
Therefore, if these are substituted into equation (2),

Le = 200000 + In ² × R × tn × 200000 = 200000 + 200000 In ² Rtn
(Or Le = 100000 + In ² × R × tn × 100000 = 100000 In ² Rtn)
It becomes.

Furthermore, since R opens and closes in the insulating oil, it is constant regardless of the current value.
Although tn varies with the current value, the mechanical time for switching opening and closing is constant regardless of the current, so the arc time is also constant. Here, although the resistance R and arc time tn change depending on the load current and operation timing, the change in resistance R and arc time tn due to the load current and operation timing is simplified in order to simplify the calculation of the possible number of operations described later. Without considering it, the resistance and arc time were omitted considering that it was the same as the rated time. In this case, 1 is used as constants of R and tn, but if other than 1, Le is calculated using the values.
Assuming that R and tn are 1 as constants, equation (2) is

Le = 200000 + 200000In ² (2) ′
(Or Le = 100000 + 100000In ² )
It becomes.

If the total amount of energy by switching does not change in the number of possible mechanical operations and the number of possible electrical operations, since Lm = Le, (1) '= (2)'

800000 = 200000 + 200000In ²
(Or 800,000 = 100000 + 100,000 In ² )
That is,

600000 = 200000In ²
(Or 700,000 = 100000 In ² )

Therefore, the number of possible mechanical operations of 600000 (or 700000) is considered to be equal to the amount of energy when the rated current is switched to 200000 (or 100000) times.

Accordingly, if the maximum value of the operable number of times is 800000 times of the mechanically operable number, the operable number equivalent amount X in the switching switch 4 can be expressed by the following equation.

X = 800000− (1 + NI1) − (1 + NI2) − (1 + NIm)
... (3)

Here, NIm is an amount corresponding to the number of possible mechanical operations of damage due to electrical reasons at the time of switching in the m-th switching. If the load current at the time of this switching m is Im,

NIm = (Im ² / 200000In ² ) × 600000 (4)
(Or, NIm = (Im ² / 100,000 In ² ) × 700000)
It is.

Here, for example, if the load current value Im is constant, the operable number of times equivalent amount X is

X = 800000-Σ {1 + 3 (Im / In) ² } (3) ′
(Or X = 800000-Σ {1 + 7 (Im / In) ² })

When the operable number of times of the switching switch (equivalent amount of operable number of new switching switches) is Y,

0 = 800000-Y {1 + 3 (Im / In) ² }
(Or 0 = 800000-Y {1 + 7 (Im / In) ² })

So

Y = 800000 / {(1 + 3 (Im / In) ² } (5)
(Or Y = 800000 / {(1 + 7 (Im / In) ² }))

It becomes.

  In equation (5), the relationship between the operable number of times Y of the switching switch and the load current value Im when the rated current value In = 200 A is shown in Table 1 and FIG.

As shown in the figure, when the load current value Im is 200 A, which is the same as the rated current value In, the operable number of times Y is 200,000 times.
That is, under the above-described rated step voltage and rated passing current, this is equal to the number of electrical operations that can be performed when the electrical circuit is opened and closed by the number of times corresponding to a predetermined electrical durability switching.
However, when the load current value Im is 100 A, the operable number of times Y is about 457,143.
When the load current value Im is 50 A, the operable number of times Y is about 673,684 times.
When the load current value Im is 0 A, the operable number of times Y is 800,000, which is the possible number of mechanical operations.

Table 1 and FIG. 2 show the number of possible operations Y when the load current value Im is constant. However, since the current value Im actually fluctuates, the current value Im at the time of switching is changed for each switching. Then, subtract the operable amount equivalent amount (1 + NIm), which has been reduced by the m-th switching, from the previous equivalent amount of operable number of times.

X _m = X _m−1 − (1 + NIm) (3) ″

Then, the operation number of possible significant amount X _m of the current that computed, to display the operational times equivalent amount with the accumulated number of operation times m.

According to the present embodiment, the number of possible operations increases as the load current value decreases. Accordingly, by calculating the operable number equivalent amount X based on the actual load current, a more accurate operable number equivalent amount X can be obtained. Therefore, it is possible to avoid a situation in which the switching switch is replaced despite the sufficient number of possible operations.
In the present embodiment, the current value Im when the switching switch 4 is opened and closed is measured and recorded, and compared with the rated current of the number of possible electrical operations and the energy amount of the number of operations, the arc contact in the switching switch 4 The amount of wear can be estimated.
Even if the power failure of the transformer or the oil removal of the switch room is not performed, the wear amount of the arc contact in the switching switch 4 can be estimated by the display by the display unit 12. Therefore, it is possible to determine whether or not it can be used beyond the number of electrical operation possible times.
In addition, the amount corresponding to the operable number of times of the switching switch displayed on the display unit 12 is recorded and stored by periodic inspection or the like, and even if the display unit 12 or the like breaks down and data is lost, It is preferable to make it.
If the 90 relay 5 includes the operation system 1 corresponding to the number of operable times, the space can be further reduced.

(Second Embodiment)
The number of times that the mechanical operation can be performed is also obtained by the following equation as an equation equivalent to the above equation (1).

Lm = Nm + Vs × I0 × t0 × Nm (6)

here,
I0: Current (0A) switched by the tap switching device when loaded
Vs: Rated step voltage t0: Arc time (arc time 0 seconds)
Nm: Number of operations that can be performed mechanically (800000)
Therefore, if these are substituted into equation (6),

That is,
Lm = 800000 ... (6) '

The number of times that electrical operation can be performed is calculated by the following equation as an equation equivalent to the above equation (2).

Le = Nn + Vs × In × tn × Nn (7)

here,
In: Rated current of the tap switching device at load Vs: Rated step voltage tn: Arc time (arc time at rated current)
Nn: Since it is the number of operations that can be electrically performed, if these are substituted into equation (7),

Le = 200000 + Vs × In × tn × 200000
Le = 200000 + 200000VsIntn

(Or, Le = 100000 + Vs × In × tn × 100,000
Le = 100000 + 100,000VsIntn)

It becomes.
Furthermore, since the step voltage is a system voltage, it is approximately constant with some fluctuations, and the rated step voltage. The arc time is also constant. Here, although the step voltage Vs and the arc time tn vary depending on the load current and the operation timing, the step voltage Vs and the arc time tn according to the load current and the operation timing are simplified in order to simplify the calculation of the possible number of operations described later. The resistance and arc time were omitted without considering the change and assuming that it was the same as the rating. In this example, Vs and tn are set to 1 as constants. However, when other than 1, Le is calculated using the values.
When Vs and tn are set to 1 as constants, equation (7) is

Le = 200000 + 200000In (7) ′
(Or Le = 100000 + 100,000In)

If the total amount of energy by switching is not affected in the number of possible mechanical operations and the number of possible electrical operations, since Lm = Le, (6) '= (7)'

800000 = 200000 + 200000In
(Or 800,000 = 100000 + 100,000In)

That is,

600000 = 200000In
(Or 700000 = 100000In)

Therefore, the number of possible mechanical operations of 600000 (or 700000) is considered to be equal to the amount of energy obtained by switching the rated current to 200000 (or 100000) times.

Accordingly, if the maximum value of the operable number of times is set to 800000 times of the number of possible mechanical operations, the operable number of times equivalent X in the switching switch 4 can be expressed by the following equation.

X = 800000− (1 + NI1) − (1 + NI2) − (1 + NIm) (8)

Here, NIm is an amount corresponding to the number of possible mechanical operations of damage due to electrical reasons at the time of switching at the m-th switching. If the load current at the time of this switching m is Im,

NIm = (Im / 200000In) × 600000 (9)
(Or, NIm = (Im / 100,000In) × 700000)

It is.

Here, for example, if the load current value Im is constant, the operable number of times equivalent amount X is
X = 800000-Σ {1 + 3 (Im / In)} (8) ′
(Or X = 800000-Σ {1 + 7 (Im / In)})

When the operable number of times of the switching switch (equivalent amount of operable number of new switching switches) is Y,

0 = 800000-Y {1 + 3 (Im / In)}
(Or 0 = 800000-Y {1 + 7 (Im / In)})

So

Y = 800000 / {(1 + 3 (Im / In)} (10)
(Or Y = 800000 / {(1 + 7 (Im / In)}))

It becomes.

  In Expression (10), the relationship between Y and Im when the rated current value In = 200 A is shown in Table 2 and FIG.

図示するように、負荷電流値Ｉｍが定格電流値Ｉｎと同じ２００Ａの場合、動作可能回数Ｙは、２００，０００回である。
すなわち、上述の定格ステップ電圧及び定格通過電流のもとで、所定の電気的耐用切換に相当する回数だけ開閉させたときの動作可能回数である電気的動作可能回数と等しい。
しかし、負荷電流値Ｉｍが１００Ａの場合、動作可能回数Ｙは、約３２０，０００回となる。
負荷電流値Ｉｍが５０Ａの場合、動作可能回数Ｙは、約４５７，１４３回となる。
なお、負荷電流値Ｉｍが０Ａの場合は、動作可能回数Ｙは機械的動作可能回数である８００，０００となる。

As shown in the figure, when the load current value Im is 200 A, which is the same as the rated current value In, the operable number of times Y is 200,000 times.
That is, under the above-described rated step voltage and rated passing current, this is equal to the number of electrical operations that can be performed when the electrical circuit is opened and closed by the number of times corresponding to a predetermined electrical durability switching.
However, when the load current value Im is 100 A, the operable number of times Y is about 320,000 times.
When the load current value Im is 50 A, the operable number of times Y is about 457,143 times.
When the load current value Im is 0 A, the operable number of times Y is 800,000, which is the possible number of mechanical operations.

  That is, also in the second embodiment, the operable number of times increases as the load current value decreases. Accordingly, by calculating the operable number equivalent amount X based on the actual load current, a more accurate operable number equivalent amount X can be obtained. Therefore, it is possible to avoid a situation in which the switching switch is replaced despite the sufficient number of possible operations.

DESCRIPTION OF SYMBOLS 1 Operation | movement possible equivalent amount calculation system 2 Voltage adjustment system 3 Tap switching device at the time of load 4 Switching switch 5 90 Relay 11 Calculation part 12 Display part

Claims (6)

A method for calculating an amount corresponding to the operable number of times of the switching switch in the on-load tap switching device,
From the number of possible mechanical operations when the operation cycle switching is repeated while starting and stopping at each tap switching in the no-voltage state,
A calculation method of calculating an amount corresponding to the operable number of times by subtracting a number obtained by adding 1 which is the number of times of mechanical deterioration and a number corresponding to the number of times of mechanical deterioration due to electrical deterioration every time switching is performed. The calculation method according to claim 1, wherein the number corresponding to the number of times of mechanical deterioration due to the electrical deterioration is obtained in consideration of a ratio of a load current at the time of switching to a rated current. NIm, which is a number corresponding to the number of times of mechanical deterioration due to the electrical deterioration, is the load current at the time of switching m times Im.
When the rated current is In,
The following formula NIm = (Im ² / 200000In ² ) × 600000
Or
NIm = (Im ² / 100,000 In ² ) × 700000
The calculation method according to claim 1, which is obtained by any one of the following expressions. NIm, which is a number corresponding to the number of times of mechanical deterioration due to the electrical deterioration, is the load current at the time of switching m times Im.
When the rated current is In,
The following formula: NIm = (Im / 200000In) × 600000
Or
NIm = (Im / 100,000In) × 700000
The calculation method according to claim 1, which is obtained by any one of the following expressions. An operation system equivalent to the number of operable times of the switching switch in the tap switching device when loaded,
From the number of possible mechanical operations when the operation cycle switching is repeated while starting and stopping at each tap change in the no-voltage state,
Each time switching is performed, a calculation unit is provided that calculates the operable number equivalent amount by subtracting the number obtained by adding 1 which is the number of times of mechanical deterioration and the number corresponding to the number of times of mechanical deterioration due to electrical deterioration. Arithmetic system. A display unit that displays the amount corresponding to the operable number of times;
The arithmetic system according to claim 5.

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