JPH0152979B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a current differential relay device that appropriately protects a power system using current information and idle end information taken in from each terminal of the power system.

[Technical background of the invention]

In recent years, multi-terminal systems have been planned for important trunk lines of ultra-high voltage systems, and digital current differential relay devices, FM current differential relay devices, etc. that use the current differential principle have been developed as protective relay devices to protect them. It's coming. Although these devices differ in the method of transmitting current information from multiple terminals, they either mutually transmit the amount of current and voltage obtained from each terminal, or
The signals are collected at one terminal and differential judgment is performed.

Here, in order to operate the system, it may be necessary to perform an operation that involves shutting down any of the terminals (two or more terminals) or disconnecting the terminal. In this case, in order to perform accurate differential determination, it is necessary to notify other terminals that the terminal is to be treated as a rest terminal. This point will be explained in detail below.

FIG. 1 shows a system configuration diagram of a current differential relay device for protecting a two-terminal system. Currents iA and iB flowing into the power transmission line 1 from current transformers 2A and 2B at both terminals A and B of the power transmission line 1 are taken into current differential relay devices 3A and 3B at each terminal. A differential current id is created from the captured current information iA and iB, and when it reaches a predetermined level, the current differential relay device operates. Further, information on the open and closed states of the power line breakers 5A and 5B of the power transmission line 1 is also simultaneously taken into the current differential relay devices 3A and 3B. The current iA, iB of the A terminal and B terminal, and the information on the disconnectors 5A and 5B are transmitted by the transmission devices 4A and 4B.
sent to each other via. FIG. 2 shows the current differential relay devices 3A, 3B and the transmission device 4 of FIG.
FIG. 4 is a block configuration diagram showing the configuration of A and 4B as an example of a digital current differential relay device. The current differential relay device 30A is composed of the following circuit. Current information iA taken in through the current transformer 2A is input to an input converter 301 that converts it into a voltage amount at a predetermined conversion ratio.
The signal is inputted to a filter 302A via A, removes unnecessary frequency components, and is taken into a sampling and hold circuit 303A. The output of the sampling hold circuit 303A is converted into a digital signal via an A/D converter 304A and written into a data memory (RAM) 306A, and at the same time a data conversion circuit 305A is sent to convert serial/parallel data into parallel and serial data. It is sent to the B terminal via the on the other hand,
Logic signals such as the current signal iB and disconnector opening/closing signals transmitted from the B terminal via the data conversion circuit 305A are written into the data memory 306A. Using the information data written in this data memory 306A, the program memory (ROM) 30
A predetermined processing program stored in 8A is executed by central processing control unit 307A. Further, an interface circuit 309A for receiving input information such as a setting value from the interface section 31A.
Consisting of

Next, the current differential relay device 30A, which detects the end of rest based on the short circuit disconnection information and control power supply abnormality information transmitted to the partner terminal, will be described with reference to FIGS. 3 and 4. FIG. 3 is a configuration diagram for detecting information on the open/closed state of the shield breaker 5A and abnormality in the control power supply. Drive power supplies P and N are auxiliary relays CBX-1,
It is a relatively high level power supply that drives CBX-2 and CBX-3, and the current differential relay device 30.
Power is also supplied to A. Current differential relay device 3
Since the internal electronic circuits and the like of 0A can be driven with a relatively low level power supply, the control power supplies ZP and ZN obtained from the control power supply device 20A which is insulated from the power supplies P and N and converted to a predetermined level are used.

First, detection of the open/closed state of the shield breaker 5A will be described. Contact 5A' and auxiliary relays CBX-1, CBX that open and close in conjunction with the opening and closing of each of the three phases of shield breaker 5A
-2, CBX-3 is connected to drive power supplies P and N, and information indicating the operation/non-operation of these auxiliary relays is taken into the buffer circuit 22A of the current differential relay device 30A, and the opening/closing information of the circuit breaker is A logical signal indicating
CBX-1LA, CBX-2LA, CBX-3LA. This signal CBX-1LA, CBX-2LA, CBX
-3LA is "1" when the line breakers of each phase are open, and "0" when they are closed.

Next, detection of control power supply abnormality will be described. If the control power supply becomes abnormal and fluctuates or is disconnected, the operation judgment of the relay device will become unreliable.
Equipped with power supply abnormality detection circuit 21A for control power supply ZP, ZN
Anomaly detection is performed. The output L of this power supply abnormality detection circuit 21A becomes "1" when an abnormality is detected.

And, Konoshiya disconnector opening/closing signal CBX-1LA,
Information on CBX-2LA, CBX-3LA and abnormality detection signal L is transmitted to the other terminal via transmission device 4A together with current information iA.

Based on the information transmitted from the A terminal, whether or not the A terminal is a rest terminal is detected by the processing of the rest end detection circuit shown in FIG. In the figure, 4a is an inhibit circuit, 4b is an OR circuit, 4c is a flip-flop circuit, 4d is an AND circuit, S=“1”, R
When = "0", Q = "1", S = "0", and when R = "1", Q = "0".

When the input L of the inhibit circuit 4a is "1", that is, when a power supply abnormality is detected, for example, A
Terminal and disconnection information CBX-1LA, 2LA, 3LA
is "1" when all three phases are open.Even if the output of the AND circuit 4d is "1", the output of the inhibit circuit 4a is not "1", and the output (=Q) of the flip-flop 4c is "1". It is not. In other words, when a power supply abnormality is being detected, the suspension will not be detected. Therefore, suspension is detected only when no abnormality is detected.

Also, if an abnormality is detected after detecting a pause,
The S input of the flip-flop becomes "0", and the output "1" of the OR circuit 4b also becomes "0" by the NOT circuit 4e, so the output of the flip-flop (=
Q) remains at "1" and the pause detection signal does not return.

[Problems with background technology]

In such a circuit, when the power supplies P and N are disconnected, the abnormality detection signal L becomes "1" depending on the timing of the disconnection of the power supplies P and N and the fall of the output ZP of the control power supply device 20A. In some cases, a dormant condition is satisfied before the terminal becomes dormant, and the terminal is treated as dormant even though it is not actually a dormant terminal. An example is shown in FIG. When the drive power supplies P and N are dropped at t=t ₀ , the output levels of the control power supplies ZP and ZN are gradually attenuated due to the structural characteristics of the control power supply device 20A, and the power supply abnormality detection circuit 21 is dropped at t=t ₁ .
A detection level is reached. Therefore, the abnormality detection signal L becomes "1" at t= _t1 . On the other hand, the breaker information due to the operation of the auxiliary relay driven by the power supplies P and N is opened after the auxiliary relay's recovery time from t= _t0 . Therefore, the disconnection information is transmitted to the other terminal first, and before the abnormality detection signal L is received, the S input of the flip-flop 4c becomes "1" and the output Q also becomes "1", so that the A terminal is not connected. This can be seen as a resting end. As a result, the current information from the A terminal is treated as zero, and the current differential relay at the receiving terminal is prevented from operating, and as shown in Figure 6, the current information between the A and B terminals is reduced _. If it is flowing, it is determined that there is an inflow, which may lead to malfunction even if there is no system fault. Furthermore, if an accident occurs outside the section, the B terminal may become erroneous or disconnected. In other words, in a current differential protection relay device that aims to protect the power system by using current information of multiple terminals of the power system, relay blocking information and disconnection information are generated when the power supply of any terminal is activated or deactivated. Due to lack of time coordination, other terminals may perform unnecessary stoppage detection, and even though the power system is operating normally, a differential current may occur, leading to malfunction of the current differential relay device. It was hot.

[Purpose of the invention]

The present invention was made with the aim of solving the above-mentioned problems, and the present invention has been made with the aim of solving the above-mentioned problems.
It is an object of the present invention to provide a highly reliable current differential relay device that accurately detects stoppage by detecting disconnection between N and N at high speed.

[Summary of the invention]

The present invention provides a current differential relay device configured to detect a terminal as a dormant terminal when a breaker is opened, and to prevent detection of a dormant terminal when an abnormality in the power supply of the corresponding terminal is detected. By installing a second auxiliary relay that can detect power loss at the corresponding terminal on the same drive power source as the auxiliary relay that responds to the opening/closing status of the disconnector, the time required to detect a power failure when the power source is disconnected can be reduced. The purpose is to detect the opening of the device at the same time as possible, thereby reliably preventing erroneous detection of the rest end of the mating terminal.

[Embodiments of the invention]

Examples will be described below with reference to the drawings. As shown in Fig. 7, when voltage is applied between drive power supplies P and N to which auxiliary relays CBX-1, CBX-2, and CBX-3 are connected, which indicate the open/close status of the circuit breaker. An energized auxiliary relay 70 is provided, and information of a contact 70a interlocked with this auxiliary relay 70 is taken into a buffer circuit. The contact information of this auxiliary relay 70 is "1" when the auxiliary relay 70 is excited.
becomes. Then, an inhibit circuit 71 is provided,
When the power supply abnormality detection circuit 21A does not detect any abnormality in the control power supply (when the abnormality detection signal L is "0"),
The contact information "1" of the auxiliary relay 70 is transmitted to the other end as LX.

In this way, by transmitting power supply abnormality information LX to the other end instead of the conventional abnormality detection signal L, auxiliary relays CBX-1, CBX-2, CBX-3
It is possible to coordinate the power supplies P and N with the auxiliary relay 70 when the power supplies P and N are disconnected, and it is possible to prevent unnecessary stop detection at the mating terminal, thereby preventing malfunction of the current differential relay device. The timing chart is shown in FIG. That is, in FIG. 8, if the drive power supplies P and N are dropped at t= _t0 , the control power supplies ZP and
The output level of ZN gradually attenuates and reaches the detection level of the power supply abnormality detection circuit 21A at t= _t1 .
Therefore, the abnormality detection signal L becomes "1". on the other hand,
Auxiliary relay CBX-1 driven between power supplies P and N,
The breaker information due to the operation of CBX-2 and CBX-3 is opened after the recovery time of the auxiliary relay from t= _t0 . Auxiliary relay 7 driven between the same power supplies P and N
0 becomes open at the same time. Therefore, the abnormality detection signal LX indicating the disconnection information and the power abnormality information at the other terminal become "0" almost simultaneously. Therefore, by inserting an on-delay timer 80 for the output of the inhibit circuit 4a to slightly delay the pause detection time, as in the pause end detection circuit shown in FIG. 9, unnecessary pauses can be detected reliably. This can be prevented.

In other words, if the power supplies P and N are disconnected, the abnormality detection signal LX and the disconnection information logic signal CBX-1LA,
Since CBX-2LA and CBX-3LA are transmitted almost simultaneously, the output of the inhibit circuit 4a is not established, and the S input of the flip-flop 4c does not become "1", preventing the A terminal from being mistakenly regarded as the rest end. . Furthermore, even if the disconnection information is transmitted slightly earlier and the output of the inhibit circuit 4a is established, the transmission difference is absorbed by the on-delay timer 80, so the S input of the flip-flop 4c does not become "1" and an error occurs. No rest edge detection is performed.

In the above explanation, we explained that the pause detection is performed at the other terminal, but when the pause is detected at the own terminal, the current iA
It goes without saying that it is also possible to control the signal to zero and transmit it to the other party's terminal. Furthermore, although the above embodiments have been explained using a two-terminal system, it is of course applicable to a multi-terminal system having three or more terminals.

〔Effect of the invention〕

According to the present invention, the shutdown is detected using the opening/closing information of the disconnector and the power supply abnormality detection information transmitted at approximately the same time, so the current differential relay device prevents incorrect handling of the shutdown end and has high operational reliability. can be obtained.

[Brief explanation of drawings]

Figure 1 is a system configuration diagram of a current differential relay device, Figure 2 is a block diagram of a digital current differential relay device, and Figure 3 is a configuration diagram of a conventional information detection system.
Figure 4 is a circuit diagram of a conventional idle end detection circuit, Figure 5 is a timing chart showing the operation of the conventional idle edge detection circuit, Figure 6 is a power system diagram to which a current differential relay device is applied, and Figure 7. 8 is a timing chart showing the operation of the rest edge detection circuit of the invention, and FIG. 9 is a circuit diagram of the rest edge detection circuit of the invention. 1...Power transmission line, 2A, 2B...Current transformer, 3
A, 3B...Current differential relay device, 4A, 4B...
...Transmission device, 5A, 5B...Shiya disconnector, 20A...
...Control power supply device, 21A...Power supply abnormality detection circuit, 22A...Buffer circuit, CBX-1, 2,
3, 70... Auxiliary relay, 71, 4a... Inhibit circuit, 4b... OR circuit, 4c... Flip-flop circuit, 4d... AND circuit, 4e...
Note circuit, 80...on-delay timer.

Claims (1)

[Scope of Claims] 1. Current information taken from each terminal of the power system, breaker information indicating the opening/closing status of the breaker, and abnormality detection information of the power supply are transmitted between the terminals or a specific In a current differential relay device that collects current at a terminal, detects a dormant terminal based on the current information when there is no power abnormality, and performs current differential calculation based on the current information, the current information is obtained. A second auxiliary relay connected to the same drive power source as the auxiliary relay that responds to the opening/closing status of the disconnector is installed, and abnormality detection information corresponding to the operating status of this second auxiliary relay is input, and the abnormality detection information corresponding to the operating status of the second auxiliary relay is input. A current differential relay device comprising a rest end detection circuit that prevents erroneous detection of a rest terminal due to a delay in the abnormality detection information.