JP2845584B2 - Step-out protection relay - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a step-out protection relay device for detecting step-out in a three-terminal transmission line.

(Prior Art) A conventional step-out detection method in a three-terminal transmission line will be described with reference to FIG.

In a three-terminal transmission line consisting of A terminal, B terminal, and C terminal, 17C and 17L are circuit breakers and disconnectors installed at A end, respectively, and 18C and 18L are circuit breakers and disconnectors installed at B end, respectively. 19C and 19L indicate circuit breakers and disconnectors installed at the C terminal. A step-out detecting relay 23 ', 24', 25 'is installed at each terminal. The step-out detecting relays 23 ', 24', and 25 'introduce the secondary circuits of the instrument transformers 20, 21, and 22 at each terminal, and transmit the phase information of the voltage or the instantaneous value of the voltage to the communication devices 26 and 27. , 28 and the transmission path 29 to each other end. At each terminal, out-of-step between all opposing terminals is determined from the secondary voltage information of the self-end instrument and the reception information of the other end. The step-out determination method for the step-out detection relay devices 23 ', 24', and 25 'in FIG. 4 includes an all-terminal AND method and an all-terminal OR method. Hereinafter, each detection method will be described.

FIG. 5 is a block diagram in which all terminals are of an AND type. FIG. 5 is a block diagram in which an A terminal is used as a reference (A terminal is its own end). Hereinafter, for convenience, the description will be made with the A terminal as a reference (own end). Self end voltage
V _A (A-end voltage) or voltage phase information 1, the other end voltage V _B (B-end voltage) or voltage phase information 2 received via the transmission system, and V _C (C-end voltage) or voltage phase Information 3 is introduced, phase difference detectors 4 and 5 for detecting the voltage phase difference between the own end (A end) and the other end (B end and C end), and step-out based on the obtained voltage phase difference. The determination units 6 and 7 include an AND circuit 40 that outputs when it is determined that both the terminal (A terminal) and the B terminal and between the A terminal and the C terminal are out of synchronization based on the determination result.

FIG. 6 shows an all-terminal OR system, but this drawing is also a block diagram based on the A terminal. Self-end voltage V _A (A-end voltage)
Alternatively, the phase information 1, the voltage V _B (B-end voltage) of the other end received via the transmission system or the phase information 2, and V _C (C
Terminal voltage) or phase information 3 to detect a voltage phase difference between the self-end and the other end, and a judging unit 6, which judges out-of-step based on the phase difference of the obtained voltage. 7 and the judgment result indicates that the own terminal (A end) is between A end and B end or A end
It is composed of an OR circuit 41 that outputs when it is determined that a step-out occurs between any of the C ends.

FIG. 7 shows an example of a phase characteristic for detecting step-out. The detection method is such that in the α region 50 and the β region 51, the phase difference between the opposite terminal voltage with respect to the own terminal voltage phase is changed from the α region 50 to the β region.
It is determined that the out-of-step trajectory has passed through the section by detecting movement from the 51 or β region 51 to the α region 50 (passing through the 180 ° line).

FIG. 8 is an example of a step-out pattern in a three-terminal transmission line. This figure shows a case where the out-of-step locus 75 passes between the branch point 76 and the B terminal. Voltage phase difference between V _A ~V _B is out-of determination A end of the main pattern, and between V _B ~V _A is B end
Voltage phase difference between V _B ~V _C, the C terminal determines that the respective step locus in voltage phase difference between V _C ~V _B present in the interval. In this case, in the all-terminal OR method, all the A-end, B-end, and C-end are tripped and step-out is separated. However, the trip between the A-end and the B-end where synchronization is maintained is also performed. The entire transmission line stops. Further, in the case of the all-terminal AND method, only the B-end for detecting out-of-synchronism is tripped for all facing terminals, and power transmission between the synchronized A-end and C-end can continue. However, in this method, if there is a pause at any terminal, even if the electrical center point at the time of step-out passes in the section, a step-out detection output is not established between the terminal and the rest, so that terminals other than the pause end are not output. There is a problem that trip cannot be performed.

The present invention has a function of determining out-of-step in a section in a three-terminal transmission line as an all-terminal AND method during all-terminal operation and as an all-terminal OR method when there is a pause, depending on the operation state of the system. It is an object of the present invention to provide a step-out protection relay capable of preventing unnecessary disconnection of a system that maintains power.

[Object of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention detects a passage of an electrical center point at the time of step-out in a protection section, and separates a system. First means for detecting out-of-step between the own end and a plurality of other ends, respectively, in the out-of-step protection relay device of the system;
A second means for detecting the other end stop, a third means operating when all of the out-of-step detection relays of the own end and the plurality of other ends determine out-of-step, And a switching means for switching between the third means and the fourth means, which operates when it is determined that any one of the terminals is out of step.

(Operation) In the present invention, the self-end (A
When the three-terminal transmission line is operating all terminals using the results of step-out determination between the terminal and the other end B and C, and the results of determination of the system operation status based on the CB / LS input conditions of each terminal. Is an all terminal AND method by the third means. Further, when there is a pause end, the output is performed by the fourth means in an all-terminal OR method.

(Example) Hereinafter, an example is described with reference to drawings.

FIG. 2 is a block diagram of one embodiment of the step-out protection relay device according to the present invention.

In a three-terminal transmission line consisting of A terminal, B terminal and C terminal, the A terminal is connected to the meter transformer 20, the step-out detecting relay 23 and the communication device 26, and the B terminal is connected to the meter transformer 21. An instrument transformer 22, an out-of-step detection relay device 25, and a communication device 28 are installed at the C-terminal, respectively. In the step-out detecting relay 23, the voltage information is input from the instrument transformer 20 to the input converter 70, is waved by the filter (FIL) 71, and is converted into digital data by the analog / digital converter (A / D) 72. . This converted data is transmitted to the transmission control unit (CC
T) The signal is transmitted from 73 to the opposite end and is introduced into the arithmetic processing unit 74. The voltage data from the opposite end is transmitted to the transmission control unit.
It is received at 73 and used by the arithmetic processing section 74 together with its own data for step-out determination. In addition, the step-out detection relay device 24 and
25 has the same configuration.

The above components can be realized more easily than the prior art. Here, an example of the processing contents of the arithmetic processing unit 74 is shown in FIG. This figure shows the processing contents at the end A in a flowchart. Step S30 is a pause detection of the B terminal,
Step S31 is a step-out detection between the A terminal and the B terminal.
Numeral 32 indicates detection of a stop of the C terminal, step S33 indicates detection of step-out between the A terminal and the C terminal, step S34 indicates that the self-end trip condition is satisfied, symbol Y indicates that the condition is satisfied, and symbol N indicates that the condition is not satisfied.

FIG. 1 shows the configuration of the present invention, and the following description will be made with reference to terminal A (own end). 1 is the voltage phase information of the voltage V _A (A-end voltage) of the own end, 2 is the voltage phase information of the voltage V _B (B-end voltage) of the other end received via the transmission system, and 3 is the transmission system. Voltage V _C (C terminal voltage) received via
4 and 5 are phase difference detectors for detecting a voltage phase difference between the own end (A end) and the other end B or C, and 6 and 7 deviate from the outputs of 4 and 5, respectively. 8 is an OR circuit having outputs of 6 and 7; 9 is a condition of a disconnector and a circuit breaker at its own end; 10 and 11 are B terminals and C terminals received through the transmission system. The conditions of disconnector and circuit breaker are shown. Reference numeral 12 denotes a circuit for detecting whether or not a terminal is a pause terminal according to the conditions of the circuit breaker and disconnector of each terminal. This output is 1 when all terminals are operated, and becomes 0 when at least one terminal is detected as a pause end. It is a logic circuit. Reference numeral 13 denotes a circuit for enabling a method of outputting a shut-off output when all the terminals are out of synchronization when there is at least one idle terminal. Reference numeral 14 denotes an AND circuit for determining out-of-step of all the terminals when all the terminals are in operation. This is a circuit that makes the method of outputting a cutoff output effective. Reference numeral 15 denotes an OR circuit having 13 or 14 outputs.

 Next, the operation will be described.

In the three-terminal transmission line shown in FIG. 2, it is assumed that the out-of-step locus 75 has passed between the branch point 76 and the B terminal. When the A terminal, the B terminal, and the C terminal are all in operation, the step-out detection relay device 23 installed at the A terminal determines that the step between the A terminal and the B terminal is step-out,
Step-out is not determined between the A terminal and the C terminal. The step-out detection relay 24 installed at the B terminal is connected between the B terminal and the A terminal, and between the B terminal and the
It is determined that step-out occurs between the C terminals. The step-out detection relay device 25 installed at the C terminal does not determine that the step between the C terminal and the A terminal is out of step, and determines that the terminal C and the B terminal are out of step. As a result, only the terminal B trips. When the terminal C is at the rest end, the step-out detection relay device 23 of the terminal A determines that the step between the terminals A and B is out of synchronization, and determines that the step between the terminals A and C is paused.
The B terminal out-of-synchronization detection relay device 24 determines out-of-synchronism between the B-terminal and the A-terminal, and determines that there is a pause between the B-terminal and the C terminal. As a result, both the A terminal and the B terminal trip.

In the above-described embodiment, the step-out detection is described by using the voltage phase comparison method. However, the present invention is not limited to this, and can be applied to all methods for detecting the step-out between the opposite terminals.

[Effects of the Invention] As described above, according to the present invention, when there is no idle end in the three-terminal system, the all-terminal AND method is used,
When there is a pause, the out-of-step is detected as the all-terminal OR method. Therefore, when out-of-step occurs during operation of all terminals on the three-terminal transmission line, unnecessary synchronization between the two terminals is maintained. Blocking can be prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram of the present invention, FIG. 2 is a block diagram of an embodiment of a step-out protection relay device according to the present invention, FIG. 3 is a flowchart showing processing contents, and FIG. FIG. 5 is a diagram for explaining the system, FIG. 5 is a diagram for explaining the all-terminals and system, FIG.
FIG. 7 is a diagram for explaining the all-terminal OR system, FIG. 7 is an example of a phase characteristic for detecting step-out, and FIG. 8 is an example of a step-out pattern. 1 ... A-end voltage, 2 ... B-end voltage 3, ... C-end voltage, 4,5 ... Phase difference detection unit 6,7 ... Step-out determination unit, 8,15 ... OR circuit 13,14 ... ... AND circuit, 12 ... Rest end detection circuit 9 ... A-end CB / LS condition, 10 ... B-end CB / LS condition 11 ... C-end CB / LS condition

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-57-193930 (JP, A) JP-A-58-99217 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H02H 3/08-3/52

Claims (1)

(57) [Claims] A step-out protection relay device of a multi-terminal system for detecting the passage of an electrical center point at the time of step-out in a protection section and separating a system. The first means for detecting out-of-synchronization between each other, the second means for detecting stop of the other end, and operation when all of the out-of-step detection relays of the own end and the plurality of other ends determine out-of-step. A third means;
A fourth means, a third means, and a fourth means, which operate when it is determined that any one terminal of the own end and the other end is out of step.
Switching means for switching between the step-out protection means and the step-out means.