JP2734305B2 - Route disconnection accident detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a route disconnection accident detecting device for detecting a route disconnection accident of a transmission line of an electric power system.

[0002]

2. Description of the Related Art Conventionally, a route disconnection accident detecting device for detecting a route disconnection accident of a transmission line of a power system and protecting the power system has been used. When the contact information of the circuit breaker in the transmission line is available when detecting the route disconnection accident, this contact information can be used for the detection logic. On the other hand, when the contact information is not available, it is necessary to make a determination using analog values of voltage and current.

FIG. 4 is a block circuit diagram showing a conventional route disconnection accident detecting device, which is used when contact information of a circuit breaker is not available. In the figure, 1B, 2B
Is a bus, 1L and 2L are transmission lines, CB is a circuit breaker connecting the buses 1B and 2B and the transmission lines 1L and 2L, and CT is a transmission line 1
PT is a current transformer for transforming a current (I dot) flowing through L to a predetermined size, and PT is a voltage transformer for transforming a voltage (V dot) applied to the transmission line 1L to a predetermined size. In this example, two lines of the transmission lines 1L and 2L are defined as one route, and both lines are cut off by the circuit breaker CB.

In FIG. 1, reference numerals 1 and 2 denote input converters for converting I dots and V dots in a current transformer CT and a voltage transformer PT into input values, 3 and 4 denote filter units, and 5 and 6. Denotes a sample and hold circuit, 7 denotes a multiplexer circuit (switching circuit), and 8 denotes an analog / digital conversion circuit. The analog / digital conversion circuit 8 converts an input value (analog value) obtained through the multiplexer circuit 7 into a digital value and sends the digital value to the processing circuit 20.

[0005] The processing circuit 20 is provided with an active power P of the transmission line 1L.
Calculating means 9 for calculating the absolute value | P of the active power P
First determining means 10 for determining whether or not | is equal to or greater than a set value K _PH (| P | ≧ K _PH ); and the absolute value | P of active power P
A second determination unit 11 for determining whether or not | is equal to or less than a set value K _PL (| P | ≦ K _PL ); and a current change rate Δ of the I dot.
A second calculation means 12 for calculating the I dot, the absolute value of [Delta] I dot | [Delta] I dot | is K? _I above (| [Delta] I dot | ≧
KΔ _I )
And the judgment output of the first judgment means 10 is set to a predetermined time T (normally,
Off-delay timer DT that performs off-delay for only several seconds)
1, an off-delay timer DT2 for off-delaying the judgment output of the third judgment means 13 for a predetermined time T (generally about several seconds), and an off-delay timer DT of the first judgment means 10
A third calculating means for calculating a logical product of the judgment output via the first judgment means, the judgment output from the second judgment means and the judgment output from the third judgment means via the off-delay timer.

In the above description, K _PH , K _PL , KΔ _I
Is a predetermined set value, and has a relationship of K _PH > K _PL . In the above description, the processing circuit 20 is realized by software processing using a microprocessor.

FIG. 5 is a diagram showing an operation range of the active power P at the time of a route disconnection accident. The active power P before the route disconnection accident is in the region (| P | ≧ K _PH ). On the other hand, the active power P after the route disconnection accident is located in the region (| P | ≦ K _PL ). That is, when a disconnection accident occurs, the active power P moves from the area, from the middle to the area as indicated by AB in the figure.

FIG. 6 shows an I dot (I ₁₎ immediately before a route disconnection accident.
Dot: before the change) and I dot immediately after the route break accident (I ₂
Dot: difference from the dot after change ΔI dot (ΔI dot = I ₂
Shows the operation area of the dot -I ₁ dot), after the route disconnection accident, | [Delta] I dot | is higher K? _I (| located in shown hatched area becomes ≧ K? _I) | [Delta] I dot.

[0009] From Figures 5 and 6, if the root sectional accident, | P | is shifted from the above K _PH to the following K _PL, and | [Delta] I dot | is seen to be a more K? _I.

In other words, according to this route disconnection accident detecting device, when | P | becomes equal to or less than K _PH (| P | <K _PH ), the judgment output from the first judgment means 10 to the third calculation means 14 is output. , The off-delay time T in the off-delay timer DT1
, The level is inverted from “H” level to “L” level.
When | P | is equal to or less than K _PL (| P | ≦ K _PL ),
The judgment output from the second judging means 11 to the third calculating means 14 immediately becomes "H" level. Moreover, | [Delta] I dot | is K? _I above (| [Delta] I dot | ≧ K? _I) and becomes, third
The judgment output from the judgment means 13 to the third calculation means 14 is
After the elapse of the off-delay time T in the off-delay timer DT2, the level is inverted from the “H” level to the “L” level.

Thus, when a route disconnection accident occurs, all of the judgment outputs to the third calculating means 14 are at "H" level for a short time, and the calculated outputs are at "H" level, and It is possible to detect a disconnection accident.

[0012]

However, according to such a conventional route disconnection accident detecting device, even when the active power P changes from not less than K _PH to not more than K _PL not caused by the route disconnection accident, | ΔI dot | may K? _I or more changes in the results and thus easily occurs erroneous detection of the route disconnection accident was low reliability.

The present invention has been made to solve such a problem, and an object of the present invention is to eliminate erroneous detection of a route disconnection accident and improve reliability.

[0014]

In order to achieve such an object, the present invention provides an absolute value | P of the active power P of a transmission line.
First determining means for determining whether or not | is equal to or greater than a set value K _PH , and the absolute value | P | of the active power P is equal to or greater than a set value K _PL (K _PH >
K _PL ) or less, and third determining means for determining whether the absolute value | Idot | of the current vector flowing through the transmission line is equal to or greater than a set value K _IH. , The absolute value of the current vector | I dot | is the set value K _IL (K _IH >
K _IL) provided with a fourth judging means for judging whether or not the following, the determination in the first determination means | becomes <K _PH | P
Thereafter, the result of determination by the second determination means is | P | ≦ K _PL ,
The determination result of the third judging means | a <K _{the IH} | I dot
After that, the judgment result by the fourth judgment means is | Idot | < _KIL
The case where a is obtained so as to detect a route disconnection accident of the transmission line.

[0015]

Therefore, according to the present invention, the active power P is cut off.
The value | P | shifts from K _PH or more to K _PL or less, and the current
The absolute value of the vector | I dot | following K _IL from above K _{the IH}
When it shifts to, it is detected as a transmission line route disconnection accident .

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A route disconnection accident detecting device according to the present invention will be described below in detail.

FIG. 1 is a block circuit diagram showing an embodiment of the route disconnection accident detecting apparatus. 4, the same reference numerals as those in FIG. 4 indicate the same or equivalent components.

The present embodiment differs from the route disconnection accident detecting apparatus shown in FIG. 4 in the configuration of the processing circuit 20 '.

The processing circuit 20 'comprises a first calculating means 9 for calculating the active power P of the transmission line 1L, and an absolute value |
First determining means 10 for determining whether P | is equal to or greater than set value K _PH (| P | ≧ K _PH ), and absolute value of active power P |
P | and second determination means 11 for determining whether or not a _{(≦ K PL | | P)} , the absolute value of the current vector | is less than the set value K _PL and second calculating means 120 for calculating the | I dot , | I dot | is _{equal to} or greater than K _IH (| I dot | ≧ K _IH ), and | I dot |
_A fourth determining means 140 for determining whether or not the value is equal to or less than _IL (| I dot | ≤K _IL ); and an OFF for delaying the determination output of the first determining means 10 for a predetermined time T (generally, about several seconds). A delay timer DT1, an off-delay timer DT3 for off-delaying the judgment output of the third judgment means 130 for a predetermined time T1 (normally, several cycles), and a third judgment means 1
A third AND that calculates the logical product of the determination output via the 30th off-delay timer DT3 and the determination output of the fourth determination means 140
An operation means 150, an off-delay timer DT2 for off-delaying the operation output of the third operation means 150 for a predetermined time T (generally about several seconds), a judgment output via the off-delay timer DT1 of the first judgment means 10 and a second The judgment output of the judgment means 11 and the off-delay timer D of the third calculation means 150
And a fourth calculating means 160 for calculating a logical product with a calculation output via T2.

In the above description, K _PH , K _PL , K _IH ,
K _IL is a predetermined set value, and K _PH > K _PL , K _IH
> K _IL . In the above description, the processing circuit 2
0 'is realized by software processing using a microprocessor. In this embodiment, the off-delay timers DT1 to DT3, the third calculating means 150 and the fourth calculating means 160 constitute a route disconnection accident detecting means. Figure 2 shows the behavior of the I dot during a route break accident.
It is a figure showing a work area. I-dod area before route cut accident
(| I dot | ≧ K _IH ). In contrast,
The I dot after the accident is disconnected in the region (| I dot | ≦
K _IL) located in the.

From FIGS. 5 and 2 shown above, when a route disconnection accident occurs, | P | shifts from K _PH or more to K _PL or less, and | I dot | changes from K _IH or more to K _IL or less. It turns out that it shifts to.

That is, according to this route disconnection accident detecting device, when | P | is equal to or less than K _PH (| P | <K _PH ), the judgment output from the first judging means 10 to the fourth calculating means 160 is output. , The off-delay time T in the off-delay timer DT1
, The level is inverted from “H” level to “L” level.
When | P | is equal to or less than K _PL (| P | ≦ K _PL ),
The judgment output from the second judging means 11 to the fourth calculating means 160 immediately becomes "H" level. When | I dot | becomes less than or equal to K _IH (| I dot | <K _IH ) (FIG. 3A)
(Point t1 shown in FIG. 3), the determination output from the third determination unit 130 to the third calculation unit 150 is inverted from the “H” level to the “L” level after the off-delay time T1 of the off-delay timer DT3 has elapsed. (Point t3 shown in FIG. 3B).
| I dot | is equal to or less than K _IL (| I dot | <
When (K _IL ) is reached (point t2 shown in FIG. 3A), the judgment output from the fourth judging means 140 to the third calculating means 150 immediately becomes the “H” level (t2 shown in FIG. 3C). point).
As a result, during the short period from the point t2 to the point t3 shown in FIG.
Level, and the operation output of the third operation means 150 becomes “H” level.

In this way, when a route disconnection accident occurs, all the outputs to the fourth calculating means 160 become "H" level for a short time, and the calculated outputs become "H" level, and the route disconnection accident occurs. Accidents can be detected.

In the above description, the absolute value | Idot | of the current vector is calculated by the following equation (1). In this equation, i (t) is the current vector I at time t.
, I (t−3) indicates an instantaneous value three samplings before the time t, that is, 90 ° before the electrical angle. | I dot | ² = [i ² (t) + i ² (t−3)] ^1/2 (1)

Here, the conventional route disconnection accident detecting device shown in FIG. 4 will be compared with this embodiment. In the conventional route disconnection fault detection device, the absolute value of the effective power P | P | is shifted from K _PH to K _PL, and | [Delta] I dot | has detected a case where equal to or more than K? _I as the root cross accident . | [Delta] I Dot | K? _I or changes in, there is also caused during transition from higher K _PH of active power P which is not due to the route cross accident to the following K _PL, in this since the conventional route disconnection fault detection device However, erroneous detection of a route disconnection accident was likely to occur and reliability was low. On the other hand, the transition of the absolute value | Idot | of the current vector from K _IH or more to K _IL or less occurs when the active power P changes from K _PH or more to K _PL or less without being caused by a route disconnection accident. Therefore, according to the present embodiment, erroneous detection of a route disconnection accident can be eliminated, and reliability can be improved.

[0026]

According to apparent the present invention since it has been described above, the absolute value of the effective power P | or not K _PH than | P
To _KPL or less and the absolute value of the current vector |
When the | | shifts from K _IH or more to K _IL or less,
Next thing is detected as the root cross accidents by eliminating false detection of route disconnection accident, it is possible to improve the reliability.

[Brief description of the drawings]

FIG. 1 is a block circuit configuration diagram showing an embodiment of a route disconnection accident detection device according to the present invention.

FIG. 2 is a diagram showing an operation range of an I dot at the time of a route disconnection accident.

FIG. 3 is a time chart for explaining the operation of the route disconnection accident detection device.

FIG. 4 is a block circuit configuration diagram showing a conventional route disconnection accident detection device.

FIG. 5 is a diagram showing an operation range of active power P at the time of a route disconnection accident.

FIG. 6 is a diagram showing an operation area of ΔI dots at the time of a route disconnection accident.

[Explanation of symbols]

 9 first calculating means 10 first determining means 11 second determining means 20 'processing circuit 120 second calculating means 130 third determining means 140 fourth determining means 150 third calculating means 160 fourth calculating means DT1 off-delay timer DT2 off Delay timer DT3 Off delay timer

Claims (1)

(57) [Claims] 1. A first determining means for determining whether an absolute value | P | of an active power P of a transmission line is equal to or greater than a set value K _PH , and an absolute value | P | K _PL (K _PH > K
_PL ) a second determination means for determining whether or not the current value is equal to or less than an absolute value | I dot | of a current vector flowing through the transmission line
Determining means for determining whether or not the current vector is equal to or greater than a set value K _IH;
A fourth determining means for determining whether or not _IL (K _IH> K _IL) less whether the determination result in the first judging means | becomes <K _PH | P
After the second determination means determines the result in the | I and ≦ K _PL | P
Therefore, the result of the judgment by the third judgment means is | Idot | <K
_{After reaching IH} , the result of the judgment by the fourth judgment means becomes | I
Tsu DOO | <route disconnection accident of the power transmission line when a K _IL
Route sectional fault detection apparatus characterized by comprising a root cross fault detection means for detecting as.