JPS63109695A - Transmitting signal processing method in remote supervisory equipment - Google Patents

Abstract

PURPOSE:To accurately recognize the order of state changes, by using relative time (elapsed time) in which communication time spent between a master station and substation is considered between the master station an substation instead of absolute time which is used as a standard. CONSTITUTION:The communication program of a master station P is stored by using absolute time T1 after the self priority level is raised immediately before a reset instruction TMS is issued. The reset instruction TMS is transmitted to substations C1, C2,<,Cn and the substations send answer signals R-TMS to the master station P after resetting their time counters. At the moment when the answer signals R-TMS are received, the master station again takes another absolute time T2 and calculate DELTAT=(T2-T1)/2. After calculation, the master station P uses (T1+DELTAT) as the counter resetting time. Therefore, the time at which state changes takes place in the substations C1, C2,...,Cn can be known accurately.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a remote monitoring device that monitors a monitoring target such as an electric power system, and in particular accurately recognizes state change times and grasps the state change order. The present invention relates to a transmission signal processing method suitable for.

[Conventional technology]

In a computer system that collects and monitors numerical information such as the status of equipment and power consumption in regionally scattered power systems,
In recent years, highly functional slave stations have been placed in electrical stations such as substations, and these slave stations transmit information to the central computer system, and also open and close switches through the slave stations based on commands from the central computer. The system is configured to do the following. An example of the overall ellipse of this system is shown in FIG.

When an accident occurs in the power system, protection systems are used to grasp the accident situation as quickly as possible, recover quickly, and minimize the scale of the accident.

Accurately understanding the operation of protective relays, etc. and their order of operation in the event of an accident is an important issue, and creating this type of report is an important function that is essential for power system monitoring systems. . For this purpose, the monitoring system has a configuration in which the slave stations add the operation time of protection relays, etc. to the status information (operation data) and send it to the central computer P. Misrecognition of the operating time is avoided by the transmission time of data to P (referred to as a station). For this purpose, each slave station C1 to Cn has a clock,
In a power system that is closely connected by power transmission lines, protection relay operations in the event of an accident span multiple electrical stations, and the accident is reported to the master station P from multiple slave stations. Under such circumstances, in order to accurately know the order of operation of relays, etc., it is necessary to synchronize the Cx-Co times of all slave stations. The need to accurately know this sequence of operations is important in identifying the location of an accident and investigating the cause of the accident. Conventionally, the following two measures have been considered and implemented regarding this point.

(1) The absolute time transmitted from slave stations C1 to C9 is transmitted to the parent JP.
In this method, data transmission delay is corrected at the master station P using a constant bias value. This correction value is calculated from the data transmission speed and data length of the communication line, but in order to ensure accuracy, the following a) to C.
) must be taken into account.

a) Rise time of modem carrier signal, b) Processing time of communication device, C) Processing time of child J:4t/114 station (2
) An example of this method is to make the absolute time of the slave station accurate and make it consistent throughout the device.

Brown Bobbery Review 9/1010-84 (
Bro Boveri Rev, 9/10 84
) are known. This method requires that the slave station C be equipped with a highly accurate standard time device, or
As shown in the figure, the time transmitted from the master station P is corrected at the slave station C by being equipped with a minute signal pulse generator and the like. This method requires as many time devices as there are slave stations C, making the entire system expensive.

To explain FIG. 3 in detail, the slave station C prepares a pulse signal for the time, and for the absolute time transmitted from the master station P,
This corrects the transmission time etc. using a minute pulse signal, and the slave station C
The absolute time of the master station P is temporarily stored in a temporary area, and the internal clock of the slave station C is set by the next minute pulse signal. For example, when data indicating 13:00 minutes and O seconds is transmitted from the R station P, the slave station C sets its internal clock to 13:01 minutes and O seconds when the minute pulse is input immediately after reception.

[Problem that the invention seeks to solve]

In the method (1) above, regarding points a) and b),
It is not uniform among each device, and it is impossible to know the degree of variation in advance. Furthermore, since these times vary depending on environmental conditions such as temperature, there is a problem in that it is not possible to accurately determine when to make corrections.

On the other hand, in the method (2) above, equipping each slave station with a highly accurate time device requires enormous equipment costs. In addition, the accuracy of knowing the time depends on how accurate minute pulse signal generators are provided in all slave stations, so it is difficult to know the actual time, such as when this accurate minute pulse signal generation is required. Problems that are difficult to solve remain.

Therefore, the present invention provides a transmission system that can accurately grasp the order of state changes without providing precise time devices in all slave stations, and without being affected by differences in communication equipment or fluctuations in environmental conditions. The purpose is to provide a signal processing method.

[Means for solving problems]

In order to solve the above problems, the present invention uses relative time (elapsed time) that takes into account the communication time between the master station and the chill, instead of the standard time in the master station and slave stations. The feature is that the reference time is determined and processed by calculation at the master station.

That is, the original first invention comprises a master station P, and a plurality of slave stations 01 to C1 installed corresponding to each monitoring target, each having a time counter, and connected to the master station via a transmission line. and a remote monitoring device that monitors the status of the monitored target by transmitting status information of the monitored target from each slave station to the master station, wherein the master station sends a command signal to the slave station to reset its time counter. Transmits TMS at a predetermined period,
After resetting its own time counter by this reset command signal, a response signal R-TMS is sent back from the slave station to the master station, and the elapsed time from the transmission time Tz of the reset command signal to the reception time 'rz of the response signal is 'rz-T
1, and 172 hours of this elapsed time, that is, (
The present invention is characterized in that the time TR at which Tz - Tt)/2 has elapsed is estimated as the reset execution time of the time counter, and the state change time of the monitored object is recognized based on this estimated reset time TR.

In addition, the second invention of the present application includes a master station and a plurality of slave stations installed corresponding to monitoring targets, each having a time counter, and connected to the master station via a transmission line, In a remote monitoring device that monitors the status of a monitored target by transmitting status information of the target from each slave station to a master station, the master station transmits a command signal to reset the time counter to the slave station; After resetting its own time counter by the reset command signal, the slave station returns a response signal to the master station, measures the elapsed time from the transmission time of the reset command signal to the reception time of the response signal, and measures the elapsed time. The time at which 1/2 of the time has elapsed is estimated to be the reset execution time of the time counter, the state change time of the monitored object is recognized based on this estimated reset time, and the recognized state change time is set as the parent. This system is characterized in that it is corrected to an absolute time within the station, and the state change information of the processes is aggregated and output in the order of the corrected absolute time.

To summarize the above, in the present invention, the time counter conventionally provided in the slave station is reset by the master station at high frequency, and the elapsed time (relative time) after the time counter is reset is utilized.

In addition, in response to the command from the i11 station to the slave station to reset the time counter (hereinafter referred to as reset command TMS), the slave station receives the reset command TMS, and after executing the reset command TMS, the master station A response indicating completion of execution (hereinafter referred to as response signal R-TMS) is sent to the reset command TM.
The method is to transmit with the same data length as S.

The master station memorizes the transmission time (T Estimated using the calculation formula.

Reset time = T1 + (Tt - Tl) 12 and
The master station sorts (classifies or rearranges) the state change information transmitted from each slave station based on the reset time, and outputs the state change information in the order in which the state change occurs. As for the output format, a screen display using a CRT display, a hard copy to a printer, etc. are used.

[Effect]

According to the present invention having the above configuration, the time counter reset command TMS is transmitted from the master station to the slave station after an elapsed time determined by the system configuration of the monitoring device. Next, in response to this reset command TMS, after the reset command is executed, a response signal R-TMS is sent back from the slave station to the master station after approximately the same elapsed time as described above.

The breakdown of the elapsed time (hereinafter referred to as transmission time) from the transmission time of the reset command TMS to the reset command execution time is generally an integrated value of the following times. That is, firstly, the time required for the master station to transmit the reset command TMS to the communication device (1iJ! station processing time), and the time required for the second communication device to raise the carrier signal of the modem and transmit the reset command TMS. The third is the time required for the reset command TMS to be transmitted via the communication line (data transmission time), and the fourth is the time required (communication device processing time).
This is the time required for the slave station to receive the reset command TMS and reset the time counter (slave station processing time).

On the other hand, the elapsed time from the execution time of the reset command TMS at the slave station to the reception time at which the response signal R-TMS is received by the master station (hereinafter referred to as response time) is the response signal R-TMS.
If S uses the same data length as the reset command TMS, it can be substantially the same as the above transmission time. This is because the configurations of the transmission path and reception path are the same, although the transmission direction is different. Second. This is because the difference in time required for the fourth communication process and the like is negligible.

From the above, if the transmission time and the reception time are substantially the same, the execution time of the reset command for the time counter located at an intermediate point in time is the time when the sum of the transmission time and the reception time is 172. It can be estimated. That is, it is expressed as TI+ (Tl Tl)/2.

In this way, by setting the estimated reset time as the standard time and recognizing the order of occurrence of status change information (succeeding relationship) based on this estimated reset time, a common absolute time can be used between the master station and the slave stations. This enables accurate sorting of status information.

According to the processing method of the present invention, a transmission/reception method between a master station and a slave station (
Regardless of point-to-point or multi-drop methods), variations in the models and performance of communication equipment, modems, etc., differences in transmission speeds, and changes in required time due to seasonal temperature changes, slave stations can The time can be determined appropriately. This makes it possible to accurately determine the time of state changes that occur within a short period of time between each slave station, and allows the master station to accurately grasp the order in which FA changes occur in the overall state of the power system. Become. Since state change data is simultaneously transmitted from the child station to pA month, the order in which the data is received does not correspond to the order in which the state changes occur.The master station arranges the state change data in the order of occurrence time. Accurate relay operation relay operation order results can be provided to the user.

〔Example〕

Next, an embodiment of the present invention will be described based on the drawings.

Overall configuration of the monitoring device FIG. 1 shows the overall configuration of the remote monitoring device according to the present invention.
A slave station Ct t Cx g . It is equipped with a counter (not shown). Each slave station Cx,
C's, . . . , C, are connected to the master station P via transmission lines of a suitable type. The master station P has a state change record file F, which allows each state change information to be sorted chronologically in the order of occurrence along with time data. The recorded information is output and displayed on a CRT or printer PRNT.

Estimation of the reset execution time of the slave station time counter FIG. 4 shows a method for estimating the reset execution time of the slave station time counter in the signal processing method of the present invention.

The communication program of the master station P raises its own priority level immediately before issuing the reset command TMS, and then captures and stores the absolute time Tl.
z, . . . , C, l, and the slave station C1.

After Cz,...,Cn reset the time counter,
A response signal R-TMS is sent to the master station P. When the master station P receives the response signal R-TMS, it takes in the time T2 again and calculates ΔT'' (Tz Tx) 12 .

The master station P sets Tz+ΔT as the counter reset time.

When the slave stations Cz, Cz, .

The state change time is determined as follows from the counter values simultaneously reported by C2, . . . t Co.

Change time = (counter value) XR + T1 Here, R is the time for the counter value 1.

According to this embodiment, the above process is executed every time at a cycle less than half of the time when the time counter overflows.
Not only can it be possible to accurately know the time of the state change that occurred within the slave station Cig C21...tcn, but also because the above processing is executed individually for each slave station C1, Cz,...Cn. , it is also possible to accurately calculate the time of state change occurring between multiple slave stations. In addition, in order to determine the standard time using the elapsed time, which is the relative time of transmission and reception when resetting the count value of the time counter in short cycles, the internal clocks in the slave stations C, 1, Cz, ..., Cn. It has the advantage that errors are not accumulated and there is no need to have an internal clock with particularly high accuracy.

Next, an example of a method for calculating the true/false state change time when a state change occurs in the monitored object will be explained based on the reset time estimated by the above method.

FIG. 5 shows an example of a method for calculating the state change time.

According to this example, the master station P calculates and stores the reset time of the time counter in the slave station from the generation time of the reset command TMS and the reset command TMS reply reception time T2 as described above. Immediately after receiving the reset command TMS, the slave station resets the count value of the time counter in its own station. According to this example, the time counter updates the count value (+1) every 2m5ec, and when the count value exceeds the maximum count. It is a mechanism to hold the value. When a state change is reported from the actual plant, the slave stations Cx, Cx, ..., Cn capture the state change data, add a count value (n), and report the occurrence of a state change to the parent MP; The master station P requests the slave stations Cx, Cx, . In addition to the reset time of , calculate the state change time.

In order to prevent the count value from exceeding, the master station P transmits a reset command TMS at approximately half the period of the counter overtime, thereby preventing the counter from exceeding.

Next, we will explain the case where an error occurs on the line when the reset command TMS is sent.

FIG. 6 shows that transmission of the reset command TMS from the master station P to the slave stations Cx, Cz, . . . Cfl has been completed, and the slave station C has completed the transmission.

Cm,...Cn reset the time counter.

This is a case where the response signal R-TMS cannot be received on the master station P side due to a line abnormality. Since the response signal R-TMS, which is the reply data to the reset command TMS, is not received, the slave station Cx
+...Sends a request to Cn to retransmit the data in the transmission buffer, which is the content most recently transmitted to the master station P.

The master station P determines whether a line abnormality has occurred between the master station and the slave station (TMS) or between the slave station and the master station (R-TMS) based on the data in the transmission buffer. If the response signal R-
If there is an error during TMS transmission, slave station C11C21...
.

It can be determined that Cn has processed the reset command TMS and reset the time counter. In this case, the correction value ΔT calculated when the previous reset command TMS was sent is used, and (TMS transmission time)+ΔT is set as the counter reset time. It is considered that there is no difference between the previous ΔT and the ΔT to be calculated this time, since changes in the temperature 2 equipment are not considered.

7. Processing in normal times from - Next, a processing method in the case of a line abnormality when transmitting a reset command from the master station will be explained with reference to FIG.

If the contents of the transmission buffer do not return the reset command TMS (that is, R-TMS), the slave stations Cs, Cz
, . . . Since C11 has not received the reset command TMS, the master station P re-executes the reset command TMS and calculates the counter reset time in response to this reset command 7MS command.

Execution of retransmission request in case of line abnormality is carried out by slave stations Cs, Cz
.

... is repeated a certain number of times until a reply is transmitted from Ca, and if no reply is received within the specified number of times, the IM station P determines that the slave station or line is permanently out of order and stops communication.

In this way, the master station calculates the exact time of occurrence of the state change data, adds the time together with detailed data such as the name of the state change point, and stores the data in the state change record file. State change data that will continue to be captured.

It is compared with the time in the record file, and the record file is sorted in chronological order and stored.

In this way, state change data is continuously processed and stored in a recording file. Since the state change due to an accident in one power system ends within a certain period of time, for example, if there is no new state change 1 minute after the last state change time, the state change due to the accident is considered to have ended. The status change record is printed or displayed to the user on a form or screen.

This record will be passed on to the person in charge of the power system's protection system and will be used to guide the readjustment of relay operating settings and design the protection system.

As described above, the time within the slave station can be accurately controlled without being affected by variations in transmission speed, equipment, or environmental conditions, resulting in the following effects.

(1) It is possible to know the time of state change with an accuracy of about 5 msec without having standard clock equipment in the slave station, and it is also possible to detect simultaneous state changes between slave stations with an accuracy of about ±5 msec.

(2) The counter is updated every minute, so 17500
A clock with a certain degree of accuracy is sufficient. Additionally, the status change records output by this device have a significant effect on confirmation and redesign of power system protection systems.

〔Effect of the invention〕

As described above, according to the present invention, the order in which the status of the monitored object changes can be accurately determined without installing a precise clock device in all slave stations and without being affected by differences in communication equipment or fluctuations in environmental conditions. can be grasped.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the overall configuration of a remote monitoring system according to the present invention, FIG. 2 is an explanatory diagram showing a conventional example of a general monitoring system, and FIG. 3 is an explanatory diagram showing a conventional time setting method. FIG. 4 is a time chart showing a method of calculating the time counter reset time in the transmission signal processing method according to the present invention, FIG. 5 is a time chart showing a method of calculating the state change time, and FIG. 6 is a time chart showing the time of response from a slave station. FIG. 7 is a time chart showing a processing method in the case of a line abnormality during transmission from the master station. P...Master station, C1-Cn...Slave station, Ti...Reset command transmission time, TZ...Response signal reception time, T
R...Reset time ΔT...Elapsed time, TMS
...Reset command, R-TMS...Response signal.

Claims (1)

[Claims] 1. A master station, and a plurality of slave stations installed corresponding to respective monitoring targets, each having a time counter, and connected to the master station via a transmission line, In a transmission signal processing method in a remote monitoring device that monitors the status of a monitored target by transmitting target status information from each slave station to a master station, the master station provides a command signal from the master station to the slave station to reset its time counter. After resetting its own time counter using this reset command signal, the slave station transmits a response signal to the master station, and calculates the elapsed time from the transmission time of the reset command signal to the reception time of the response signal. The time counter is estimated to be the reset execution time of the time counter at the time when 1/2 of the elapsed time has elapsed, and the time when the state of the monitored object changes is recognized based on this estimated reset time. A transmission signal processing method in a process monitoring device. 2. Transmission in a remote monitoring device in the method according to claim 1, characterized in that the reset command signal is transmitted at a cycle shorter than the transmission/reception execution cycle of status change information between the master station and the slave station. Signal processing method. 3. A master station and a plurality of slave stations installed corresponding to the monitored targets, each having a time counter, and connected to the master station via a transmission line, and transmitting status information of the monitored targets to each slave station. In a transmission signal processing method in a remote monitoring device that monitors the state of a monitored object by transmitting signals from a station to a master station, the master station transmits a command signal to reset a time counter to the slave station, and the reset command is After resetting its own time counter by the signal, the slave station returns a response signal to the master station, measures the elapsed time from the sending time of the reset command signal to the receiving time of the response signal, and calculates 1 of this elapsed time. The time when the time counter is reset is estimated to be the time at which the time counter is reset. A transmission signal processing method in a remote monitoring device, characterized in that the state change information of the process is corrected to an absolute time in the corrected absolute time order and outputted. 4. The method according to claim 2, characterized in that the reset command signal is periodically transmitted at a shorter cycle than the transmission/reception cycle of status change information between the master station and the slave station. Transmission signal processing method in equipment.