JP5361552B2 - Distance relay device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a distance relay device adapted to speed up in operating time. <P>SOLUTION: The distance relay device includes: a distance computation unit 1 that computes impedance using a voltage and a current input from a power system and computes a distance to an accident point based on the impedance; a direction computation unit 2 that computes the direction of the accident point based on a voltage displacement indicating a difference between a voltage before an accident and a voltage after the accident and a current displacement indicating a difference between a current before an accident and a current after the accident; and a determination unit that determines whether an accident has occurred in a predetermined protective section based on the computed distance and direction. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a distance relay device that detects a short-circuit accident and a ground fault that occur in a power transmission line and removes the accident from the system to protect the power transmission system.

  The conventional distance relay device includes a directional relay that determines the direction of the accident point viewed from the installation point of the distance relay device using the voltage and current input from the power system, and a distance relay that determines the distance to the accident point. It is configured to determine whether or not the accident is in the protection zone by the combination, and to operate the protection device in the case of an accident in the protection zone (see, for example, Patent Document 1). Non-Patent Document 1 proposes algorithms such as phase shift calculation and phase difference calculation that can be used to determine the operating range of the direction relay.

  In such a distance relay device, it is necessary to reinforce the digital filter and increase the number of operation confirmations in order to operate normally even with a distorted waveform at the time of an accident, and the operation time tends to increase. On the other hand, there is a strong demand for removing accidents at high speed.

JP 2004-48855 A

Electric Cooperative Research Volume 50 No.1 "Second Generation Digital Relay"

  However, according to the above-described conventional technology, the direction relay sometimes becomes a bottleneck for operating at high speed against an accident in the protection section. For example, the power receiving end exists in a region behind the distance relay device, and the direction relay does not always operate. Therefore, when an accident occurs, the direction of current and voltage changes from the rear to the front. For this reason, the operation time may be delayed compared to the power transmission end due to a transient change in the filter and direction calculation results.

  This invention is made | formed in view of the above, Comprising: It aims at obtaining the distance relay apparatus which can speed up operating time.

  In order to solve the above-described problems and achieve the object, the present invention calculates a distance using a voltage and a current input from a power system, and calculates a distance to an accident point based on the impedance. And a voltage displacement representing a difference between the voltage before the occurrence of the accident and the voltage after the occurrence of the accident, and a current displacement representing a difference between the current before the occurrence of the accident and the current after the occurrence of the accident, A first direction calculation unit that calculates the direction of the accident point; and a first determination unit that determines whether or not the accident is within a predetermined protection section based on the distance and the direction. It is characterized by.

  According to the present invention, there is an effect that the operation time of the distance relay device can be increased.

FIG. 1 is a characteristic diagram of a directional relay. FIG. 2 is a diagram illustrating a relationship between the power flow and the operating range of the direction relay. FIG. 3 is a diagram illustrating an example of a configuration of the distance relay device according to the first embodiment. FIG. 4 is a diagram illustrating a relationship between voltage data and current data input from the power system, and voltage displacement data and current displacement data. FIG. 5 is a diagram illustrating an example of a configuration of the distance relay device according to the second embodiment. It is a figure which shows an example of the circuit structure of an output time adjustment part. FIG. 7 is a time chart of the operation of the distance relay device of the second embodiment.

  Embodiments of a distance relay device according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
First, the detail of the said subject is demonstrated. FIG. 1 is a characteristic diagram of a directional relay. The shaded portion in FIG. 1 indicates the operating range of the direction relay. The characteristics of the directional relay as shown in FIG. 1 can be realized by typical phase shift calculation and phase difference calculation algorithms as described in Non-Patent Document 1, page 24, Table 1-1-2.

First, assuming that the current voltage at time t is V (t), the current is I (t), and the value of I (t) shifted by θ ° is I (t) （θ, then I (t) Ｉθ and V The range in which the phase difference φ of (t) is ± 90 ° is defined as the operating range of the direction relay. That is, when the following equation (1) is satisfied, it is determined that the accident is within the protection section, and the protection device is operated.
V (t) · I (t) ∠θ cos φ ≧ 0
= V (t) · I (t) ∠θ + V (t−90 °) · I (t−90 °) ∠θ ≧ 0
... (1)

  From the above equation (1), the voltage uses data at time t and data 90 ° before time t. In addition, when the phase shift calculation of θ is executed using the data at time t and the data 90 ° before time t, the current uses data 180 ° before time t.

  For example, when data from time t to data 180 ° before time t is used for the digital filter, the direction relay requires data 360 ° before time t for the direction determination at the time of the accident. For this reason, a maximum of one cycle is expected as the operation delay of the direction relay, which may become a bottleneck for operating the distance relay device at high speed.

  FIG. 2 is a diagram illustrating a relationship between the power flow and the operating range of the direction relay. The shaded area in FIG. 2 indicates the impedance seen by the distance relay device in a state where the current is flowing. When the load power flow is flowing, the direction relay is always operating (existing in the front area) at the power transmission end, and therefore continues to operate even when a forward accident occurs. Conversely, at the power receiving end, the direction relay is always inoperative (existing in the rear region), so the direction of current and voltage changes from the rear to the front when an accident occurs. For this reason, operation time may become slow compared with a power transmission end because of a transient change of a filter and a direction calculation result.

  The first embodiment of the present invention that solves the above problems will be described below. FIG. 3 is a diagram illustrating an example of a configuration of the distance relay device according to the first embodiment.

  As shown in FIG. 3, the distance relay device according to the first embodiment includes a distance calculation unit 1, a direction calculation unit 2, an accident detection determination unit 3, an AND unit 4A, and an AND unit 4B. Yes.

  The distance calculation unit 1 calculates the distance (impedance) to the installation point of the distance relay device using the voltage and current input from the power system. The direction calculation unit 2 uses the voltage displacement data representing the difference between the voltage before the integer cycle and the current voltage and the current displacement data representing the difference between the current before the integer cycle and the current current to determine the direction of the accident point. calculate.

  The accident detection determination unit 3 determines whether the voltage displacement data is equal to or greater than a predetermined threshold (first threshold) and the current displacement data is equal to or greater than a predetermined threshold (second threshold). Whether or not an accident has occurred is determined. Specifically, it is determined that an accident has occurred when the voltage displacement data is greater than or equal to the first threshold and the current displacement data is greater than or equal to the second threshold.

  The AND unit 4A calculates a logical product of the output of the direction calculation unit 2 and the output of the accident detection determination unit 3. The AND unit 4B calculates the logical product of the output of the AND unit 4A and the output of the distance calculation unit 1.

  The distance relay device uses the direction element output output from the AND unit 4A and the distance relay output output from the AND unit 4B in this way to determine whether or not there is an accident within the protection section. Part (not shown).

  Next, the operation of the distance relay device of the present embodiment will be described. As described above, the direction calculation unit 2 calculates the accident point direction using the voltage displacement data and the current displacement data representing the difference with respect to the voltage and current before the integer cycle. For this reason, the voltage displacement data and the current displacement data are usually zero before the accident.

  That is, normally, the direction calculation unit 2 does not output an ON signal. The direction calculation unit 2 latches (stores) data for one cycle before the integer cycle before the accident using the operation output of the accident detection determination unit 3 as a trigger. Then, during the accident, the direction calculation unit 2 repeatedly uses the stored data for one cycle as pre-accident data, and obtains voltage displacement data and current displacement data that are differences from the current data. After the accident is removed, the stored pre-accident data is reset (deleted).

  FIG. 4 is a diagram illustrating a relationship between voltage data and current data input from the power system, and voltage displacement data and current displacement data. In the example of FIG. 4, when an accident occurs, the voltage before the accident appears as voltage displacement data, and the current at the time of the accident appears as current displacement data.

  As described above, according to the present embodiment, since the data representing the voltage and current displacement before and after the accident is used, the voltage displacement data and the current displacement data before the accident are zero. That is, since the output of the direction calculation unit 2 after the occurrence of an accident changes from a zero state, a transient change in the filter and calculation output can be reduced as compared with the conventional method. For this reason, the response time of the direction calculation unit 2 can be increased. That is, it is possible to obtain a distance relay device that increases the operating time.

  From the viewpoint of the accident form, the displacement of voltage and current is the largest in the near-end accident that requires high-speed operation. For this reason, in the present embodiment using the displacement data of voltage and current, it is difficult to receive an operation delay due to the influence of a digital filter or the like, and this can also speed up the calculation of the direction element.

Embodiment 2. FIG.
FIG. 5 is a diagram illustrating an example of a configuration of the distance relay device according to the second embodiment. As shown in FIG. 5, the distance relay device of the second embodiment includes a distance calculation unit 1, a direction calculation unit 2, an accident detection determination unit 3, an AND unit 4C, an AND unit 4D, and an output time adjustment. A unit 5, a direction calculation unit 6, and an OR unit 7 are provided.

  In FIG. 5, the functions of the distance calculation unit 1, the direction calculation unit 2, and the accident detection determination unit 3 are the same as those in the first embodiment, and thus the same reference numerals are given and description thereof is omitted.

  The direction calculation unit 6 determines the accident point direction by using the voltage and current input from the power system in the same manner as in the past.

  The output time adjustment unit 5 limits the time during which the direction calculation unit 2 outputs the output value to a certain period. FIG. 6 is a diagram illustrating an example of a circuit configuration of the output time adjustment unit 5. As shown in FIG. 6, the output time adjustment unit 5 includes return timers 8A, 8B, and 8C, an operation timer 9, and an AND unit 4E. In the circuit shown in FIG. 6, the operation of the direction calculation unit 2 can be locked for the time set by the return timer 8C after the time set by the operation timer 9 elapses after the direction calculation unit 2 operates.

  Returning to FIG. 5, the AND unit 4 </ b> C calculates a logical product of the output of the direction calculation unit 2 and the output of the output time adjustment unit 5. The OR unit 7 calculates a logical sum of the output of the AND unit 4C and the output of the direction calculation unit 6. The AND unit 4D calculates a logical product of the output of the OR unit 7 and the output of the distance calculation unit 1.

  Next, the operation of the distance relay device of the present embodiment will be described. As described above, the direction calculation unit 2 uses the displacement data of the voltage and current after the accident with respect to the voltage and current before the accident to increase the speed. Then, in order to calculate the displacement data, the direction calculating unit 2 needs to use the voltage data and current data before the accident and before the accident from the voltage data and current data after the accident. Further, it is desirable that the direction calculation unit 2 can accurately acquire the data before the integer cycle even when a frequency shift before and after the accident occurs.

  However, frequency fluctuations may occur during an accident, and the sampling interval may deviate from the electrical angle of the desired system frequency. And, as in Embodiment 1, when continuing to use the voltage data and current data before the accident latched by the trigger by the operation output of the accident detection determination unit 3, due to the frequency fluctuation after the accident, the cycle of the data before the accident, The time difference from the post-accident data cycle may increase over time. For this reason, the problem that the direction calculation error using the displacement data which is the difference between the pre-accident data and the post-accident data gradually increases with time after the accident.

  Therefore, in the present embodiment, the output time adjustment unit 5 limits the operation output time of the direction calculation unit 2 to a certain time after the accident (for example, one cycle). As a result, it is possible to reduce the influence of errors due to frequency fluctuations before and after the accident. In addition, by limiting the operation output time of the direction calculation unit 2, there is an advantage that the process of latching (storing) the pre-accident data by detecting the accident is unnecessary.

  Further, in the present embodiment, high-speed and stable operation is possible by taking a logical sum with the conventional direction calculation unit 6 that is less affected by frequency fluctuations. As a result, it is possible to obtain a distance relay device that increases the operating time even when a transient frequency fluctuation occurs during an accident.

  Further, the displacement data used by the direction calculation unit 2 appears at the time of accident and at the time of accident removal. If the direction calculation unit 2 operates during accident removal, the distance relay device may malfunction, but the output time adjustment unit 5 limits the operation output time of the direction calculation unit 2 to a certain time after the accident. Such a malfunction can be avoided.

  By configuring as described above, the influence of the frequency fluctuation is small during a certain time (for example, one cycle) after the occurrence of the accident. Therefore, the calculation of the direction calculation unit 2 is executed at high speed while minimizing the influence of the frequency fluctuation. It becomes possible. Since the output of the direction calculation unit 2 is turned off after a predetermined time, the addition of the direction calculation unit 6 can ensure high speed operation and stability against frequency fluctuation. As described above, according to the present embodiment, it is possible to obtain a distance relay device with an increased operation time even when a transient frequency fluctuation occurs at the time of an accident.

  Next, a time chart of the operation of the distance relay device according to the second embodiment will be described. FIG. 7 is a time chart of the operation of the distance relay device of the second embodiment. A to E in FIG. 7 indicate output values (ON or OFF) at points A to E shown in FIG. 5, respectively.

  After the accident occurs, the logic output A of the direction calculation unit 2 is turned on after t1 time, and the output is held for t2 time according to the set time of the output time adjustment unit 5. The logic output B of the direction calculation unit 6 is turned on after (t1 + t3) time from the occurrence of the accident and turned off after t4 time from the accident removal. Therefore, the direction element output C is turned on after t1 time after the occurrence of the accident, and turned off after t4 time after the accident is removed.

  Further, the logic output D of the distance calculation unit 1 is turned on (t1 + t5) time after the occurrence of the accident and turned off (t4 + t7) time after the accident is removed. Therefore, the distance relay output E is turned on (t1 + t5) time after the occurrence of the accident, and turned off t4 hours after the accident is removed.

  As described above, according to the present embodiment, compared with the conventional case where the logical product of the output A of the distance calculation unit 1 and the output B of the direction calculation unit 6 is used as the distance relay output, the speed is increased by t6 hours. Can be realized.

DESCRIPTION OF SYMBOLS 1 Distance calculation part 2 Direction calculation part 3 Accident detection determination part 4A, 4B, 4C, 4D, 4E AND part 5 Output time adjustment part 6 Direction calculation part 7 OR part 8A, 8B, 8C Return timer 9 Operation timer

Claims (4)

A distance calculation unit that calculates the impedance using the voltage and current input from the power system, and calculates the distance to the accident point based on the impedance;
Based on the voltage displacement that represents the difference between the voltage before the occurrence of the accident and the voltage after the occurrence of the accident, and the current displacement that represents the difference between the current before the occurrence of the accident and the current after the occurrence of the accident, the accident A first direction calculation unit for calculating the direction of the point;
Based on the distance and the direction, a first determination unit that determines whether the accident is within a predetermined protection section;
A second direction calculation unit for calculating the direction of the accident point based on the voltage and current input from the power system after the occurrence of the accident;
With
Based on the distance, the direction calculated by the first direction calculation unit, and the direction calculated by the second direction calculation unit, the first determination unit is an accident within the protection section. distance relay apparatus characterized that you determine whether. A distance calculation unit that calculates the impedance using the voltage and current input from the power system, and calculates the distance to the accident point based on the impedance;
Based on the voltage displacement that represents the difference between the voltage before the occurrence of the accident and the voltage after the occurrence of the accident, and the current displacement that represents the difference between the current before the occurrence of the accident and the current after the occurrence of the accident, the accident A first direction calculation unit for calculating the direction of the point;
Based on the distance and the direction, a first determination unit that determines whether the accident is within a predetermined protection section;
A second direction calculation unit for calculating the direction of the accident point based on the voltage and current input from the power system after the occurrence of the accident ;
An output time adjustment unit that limits a time during which the direction calculated by the first direction calculation unit is output to a predetermined period;
With
Based on the distance, the direction calculated by the first direction calculation unit, and the direction calculated by the second direction calculation unit, the first determination unit is an accident within the protection section. Determining whether or not
Distance HanareTsugi collector said. A distance calculation unit that calculates the impedance using the voltage and current input from the power system, and calculates the distance to the accident point based on the impedance;
Based on the voltage displacement that represents the difference between the voltage before the occurrence of the accident and the voltage after the occurrence of the accident, and the current displacement that represents the difference between the current before the occurrence of the accident and the current after the occurrence of the accident, the accident A first direction calculation unit for calculating the direction of the point;
Based on the distance and the direction, a first determination unit that determines whether the accident is within a predetermined protection section;
A second determination unit that determines whether the voltage displacement is equal to or greater than a predetermined first threshold and whether the current displacement is equal to or greater than a predetermined second threshold ;
With
When the voltage displacement is equal to or greater than the first threshold value and the current displacement is equal to or greater than the second threshold value, the first determination unit determines whether the first displacement is within the protection interval based on the distance and the direction. To determine whether the accident
Distance HanareTsugi collector said. A distance calculation unit that calculates the impedance using the voltage and current input from the power system, and calculates the distance to the accident point based on the impedance;
A voltage displacement representing a difference between the voltage for one cycle before the integer cycle before the accident occurrence and the voltage after the accident occurrence, and the current for one cycle before the integer cycle before the accident occurrence and after the accident occurrence A first direction calculation unit that calculates a direction of the accident point based on a current displacement representing a difference from the current;
Based on the distance and the direction, a first determination unit that determines whether the accident is within a predetermined protection section;
A distance relay device comprising:

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