JPS6369418A - Sampled signal synchronizing system - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sampling signal synchronization system that is used directly in a protective relay device, for example, in a power transmission line.

[Conventional technology]

In the digital protective relay device E, the current at both ends is PCM
(Pulse Code Modulation) and compare them with each other, carrier relays have come to be used.

In this comparative protective relay device, the instantaneous values of currents at both end stations of a power transmission line are sampled at regular intervals, A/D converted, and then transmitted to each other station using, for example, a micro line. System failures in the power transmission line are monitored by comparing the values with those of the station.

In this case, the sampling timing at both terminal stations must be the same time, and the time from when data is sent until it is received by the other station, that is, the transmission delay time, is larger than the sampling period and Since it is normal that the sampling timing is doubled, a series of repetition numbers must be assigned to the sampling timing, and data sampled at the same time at both terminal stations must be transmitted with the same number. In the protective relay device of this type, a means of synchronizing the sampling timing and the sampling number is an extremely important issue.

Conventionally, this type of signal synchronization method was already developed in Japanese Patent Application Laid-Open No.
-49645 etc. have been proposed. This conventional method will be briefly explained.

FIG. 4 is an explanatory diagram showing the principle of the conventional system.

Here, the terminal station that takes the initiative in synchronization is called the "master station."

The side terminal station that performs slave synchronization is called a slave station.

It depicts the temporal relationship regarding the transmission and reception of data with a specific sampling number (hereinafter, the data sent from the master to the slave station is abbreviated as Sum, and the data sent from the slave station is abbreviated as S). It is assumed that the time it takes for S to arrive at the slave station and the time it takes for 52 to arrive at the master station after leaving the slave station are equal to each other to the extent that they can be ignored as facts, and this is defined as the transmission delay time Td.

In this way, a transmission line with equal vertical transmission delay times can actually be constructed. In addition, there is a precondition that the transmission period T (Sl and S2) should be at least twice the maximum value of mTd, taking into account fluctuations.

In Fig. 4, from the transmission of Sl at the main station, 5
The time until reception of 2 is set as TI, and this time is measured at the main station. The time from the transmission of S2 at the slave station to the reception of 3-1 is defined as Tz, and this time T2 is measured at the slave station. Then, the master station incorporates the above-mentioned time T1 into the data transmission format JHj and sends it to the slave station, which receives this time T18. Further, the reverse E slave station sends the above-mentioned time T2 to the master station, and the master station receives it.

At this time, (a) in FIG. 4 is a case where the downward diagonal line indicating the transmission of Sl from the master station and the upward diagonal line indicating the transmission of S from the slave station intersect with each other fζ.

The case where the relationship TI+T, -2Ta is established is shown.

(a) in FIG. 4 shows a case where the transmission of 82 from the slave station is delayed in time from the S (near) transmission from the master station, and the phase (timing) of the clock pulse of the slave station transmitter is Advancing a little further, we can see that the entire transmission from the slave station must be moved to the left as shown by the arrow in the figure. In other words, if h T+> T2, the transmission from the slave station is accelerated,
If maf:T, <T, it can be determined that the transmission 4g from the slave station needs to be delayed.

, ', tt is the entry of notification of one-sided wife of 4-year-old-2-year-old (h)
Alternatively, the phase of the clock pulse may be controlled at both terminal stations to achieve TI-T. and.

If T, swT, then Sl and 82 were received (transmitted at the same time, therefore, all operations including data of other sampling numbers are performed at the same time on the master station and slave station). This completes the synchronization of the sampling signals.

According to the method described in ζ, the sampling timings of the main station and the slave station are matched by matching the transmission timings of the data Sl and S2 of the same sampling number determined in advance. At this time, should either the main station or the slave station advance the phase of the clock pulse in order to match the sampling timing?

The adjustment time width for delaying or matching is at most 1/2 of the transmission cycle T of data SL, $2 of a specific sampling number. If the sampling timing is shifted, that is, the adjustment time width is shifted all at once, data transmission and transmission timing will become inconsistent, resulting in a received data error at the receiving end, so in reality This means that the sampling timing is shifted by an extremely short amount of time within a range that does not cause a received data error, and this is repeated multiple times to shift the final adjustment time width. For this reason, it took a long time to synchronize the sampling signals. Also.

The time measured for sampling synchronization, that is, the time from when the own station transmits data s1 or S2 of a specific sampling number until it receives data S2 or Sl of the same sampling number from the other station, is the time measured for sampling synchronization. It is necessary to be able to measure the period T of transmitting number data. It depends on the accuracy of time measurement,
A timekeeping counter with a relatively large number of bits is required.

Therefore, the time data (Tl or T2
) is also large, and occupies as many bits as the transmission format J:l.

Furthermore, in the method disclosed in Japanese Patent Application Laid-Open No. 50-49645, the time required for sampling synchronization is measured in each of the master station and the slave station, and the measured time data is transferred from the master station to the slave station, and from the slave station to the master station. It is an essential condition to be able to transmit data to and from each other.

For this reason, it is necessary to incorporate the time measurement data described below into the data transmitted to the partner station, which imposes restrictions on the transmission format and impairs transmission efficiency. Figure 4 (b
) is the case where Sl and 82 do not intersect, but as in FIG. 4(a), it is necessary to ensure that 81 and 82 are transmitted at exactly the same time. There is the same problem as when the two intersect.

[Problem that the invention seeks to solve]

In the sampling synchronization method disclosed in Japanese Unexamined Patent Application Publication No. 50-49645, in order to match the sampling timing,
It was necessary to shift the specific data by a maximum of 1/2 of the transmission cycle T, and it took a long time to achieve synchronization. Further, the measurement time for synchronization adjustment is required for the transmission station period T, and the number of bits is large, and a large amount of circuitry and hardware for time measurement is required.

Furthermore, the measured time data for synchronization adjustment must be transmitted to and from the other station.

It reduces the transmission efficiency of the system, and the transmission format J:E
There were problems such as a large number of data lengths and poor transmission efficiency.

This invention was made in order to solve the above-mentioned problems, and it is possible to match the sampling timings of the main station and the slave station in a short time.

It eliminates the need to transmit hourly data between opposite stations that perform synchronization adjustment, resulting in extremely high transmission efficiency, and allows time measurement at stations that perform synchronization adjustment to easily reduce the number of bits of time data in a short time. The purpose is to obtain a sampling synchronization control method that can be shortened, requires less hardware, and can be performed without mutual transmission of 01 time data.

[Means for solving problems]

The sampling signal synchronization method according to the present invention is as follows.

Master station or slave station [When data with a specific sampling number is received, flag information indicating reception is sent back to the other station after a certain sampling interval, and either the master station or slave station By measuring the time from the sampling timing to receiving the above flag information and recognizing the time from when the own station sends data of a specific sampling number until receiving the above flag information, communication with the other station can be made. The transmission delay time is calculated, the sampling timing of the own station is moved, the sampling timing is synchronized, and the sampling numbers are controlled so as to match.

[Effect]

In the sampling signal synchronization method of this invention, data indicating a specific sampling number is transmitted from the slave station to the master station, and when the master station receives data of this specific sampling number, the sampling timing of the master station and the reception timing from the slave station are synchronized. If they do not match, send flag information indicating "advance control or r-delay control" to the slave station, k.

The master station sampling timing f immediately after receiving the data of the specified sampling number is returned to the iron slave station. If the sampling timing of the master station and the timing of reception from the slave station completely match, the master station returns flag information indicating 1 match to the slave station at the next sampling timing of the master station. That is, after a certain sampling interval (in this case, one sampling timing), flag information indicating 'timing match' is returned to the other station.

The slave station receives flag information indicating this 'timing match,' but at this time, it measures the time from the slave station's most recent sampling timing until it receives the tortoise flag information.
For 1/2 hour of this measurement time, own station (here slave station)
The sampling timings of the main station and slave stations are controlled to be shifted so that only the sampling timings of the master station and slave stations match.

At this time, the transmission timing of the slave station is fixed without changing.
It is assumed that only the sampling timing of the slave station is changed.

Then, the number of sampling timings of the own station (i.e., the number of sampling cycles) from when the slave station transmits data of a specific sampling number until the other station returns flag information indicating reception of data of this specific sampling number.
8.Measure and recognize the transmission path from your own station to the other station] You can know the transmission delay time Td, and you can also know the difference in sampling numbers with the other station. Therefore,
The sampling number of the own station is changed so as to eliminate the sampling number difference with the other station, and both the sampling number and the sampling timing are made to match, and the sampling signals of both end stations are synchronized.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, T represents the period of the sampling number, which here is 1 cycle (equivalent to 360 electrical degrees) at the frequency of the power system (50H2 or 60H2). To
is the sampling timing period, here electrical angle 8
Set to 0 degrees. Data of a specific sampling number is 82 which is transmitted from the slave station to the master station. In FIG. 1, the specified sampling number is "O".

At this time, Ts receives data on which flag information Fm indicating that data S2 of a specific sampling number has been received from the main station, which is the other station, is carried by the slave station f.

This is the time from the previous sampling timing.

The flag information Fm indicates that the main station has received data S2 with a specific sampling number from the partner station.

This flag information also has the meaning of indicating whether the reception timing completely coincided with the sampling timing of the own station, that is, the main station, or whether it deviated from it.

FIG. 1 is an explanatory diagram showing the principle of the present invention, and depicts the temporal relationship regarding data transmission and reception between the master station and the slave station, and shows the time taken for data S2 sent from the slave station to arrive at the master station , flag information Fm sent from the main station arrives at the main station (
It is assumed that the time until the transmission delay time is virtually negligible and equal to each other, and this is defined as the transmission delay time 11]Td.

In FIG. 1, the operation will be explained first.

The sampling timing at the main station and slave station is 8 electrical degrees.
The interval is 0 degrees. Therefore, a sampling number is assigned to each sampling timing, and the sampling numbers are 0, 1, 2, . It is expressed by 12 numerical values: ill, . . . 9, No, 11. The sampling timing interval To between the master station and the slave station is such that data S2 of a specific sampling number is transmitted from the mutual slave station at regular intervals (T = T, x 12 ). 82 sent from slave station
arrives at the main station after a transmission delay time Td. At this time,
The main station checks and determines whether the sampling timing of its own station and the reception timing at which data S2 arrives completely match.

When the master station receives 82 from the slave station, it always sends the transmission data lζl to the slave station at the next sampling timing.
Data is transmitted from the master station to the slave station with flag information Ftn (hereinafter abbreviated as flag Fm) indicating '-52 reception'. In the example shown in Figure 1, the main station has sampling number “9”.
”, E7-82 is received from the slave station, and the master station puts the flag Fm in the transmission data with the sampling number “lO” and sends it back to the slave station.The slave station receives the flag from the master station. Upon receiving Fm, in order to know the time from when the own station transmits data S2 to when it receives flag Fm, it recognizes that the flag Fm reception timing is the sampling number "7" of the own station. Then, each sampling getta i : ・l )−fn) A
f:, -7-'l/y"-Ai room-a-
Measure the time from the ringing timing to receiving the flag Fm as Ts.

First, the first stage of sampling timing synchronization control between the master station and the slave station will be explained based on FIGS. 1 and 2.

Data S2 transmitted from the slave station arrives at the master station fζ.

The reception timing is the sampling timing of the main station (
30° interval), that is, the transmission timing of the main station and the complete Iζ
If they match, the main station sets a flag F indicating 'timing match'.
O to the slave station at the transmission timing of the primary master station.

In other words, it does not necessarily occur from the data S2 reception timing.

The flag FO is returned to the slave station at a timing delayed by 10 hours from the l sampling timing.

Next, if the reception timing of data S2 from the slave station is different from the transmission timing of the master station, the master station will send the data to the slave station.
'Flag information for advance control or one-delay control, Fl, F2, respectively, is returned at the next transmission timing.

In response to the following operations of the master station, the slave station receives information from the master station.
Flag Fl or F2 of advance control or r-lag control J
When it receives this, it controls the transmission timing of the slave station to slightly advance or delay the phase (timing) of the clock pulse of the slave station transmitter, as instructed by the flag Fl or F2 from the master station.

As a result, the transmission timing of data S2 from the slave station changes gradually in the direction of arrow A in the example of FIG.

After a certain period of time has elapsed, the reception timing of the main station f and the transmission timing of the main station, in other words, the sampling timing, will completely match. When the reception timing of the data S2 at the master station and the master station transmission timing completely match, the master station transmits a flag FO indicating 'timing coincidence J' to the slave station.

When the slave station receives the flag FO, it stops the phase control of the slave station transmitter and fixes the transmission timing at that point.

Then, the slave station transmission timing is fixed and does not change until the flag F1 or F2 is received from the master station again. During the period when this flag FO is being transmitted, a certain relationship is established between the transmission timings of the master station and the slave station.

In the slave station, after the slave station sends data S2,
To know the time until receiving flag FO.

The time from the sampling timing immediately before the flag FO arrives until the flag FO is received is measured as Ts.

Figure 2 shows a state in which the reception timing of data S2 from the slave station completely coincides with the transmission timing of the master station, or in other words, the sibling timing of the master station, and the flag FO is transmitted from the master station to the slave station. This is a state in which the master station and slave station have a certain relationship.

In this state, control is performed to match the sampling timings of the master station and the slave station.As is clear from FIG. (The following relationship holds true between + and measurement time Ts.

O≦Ts≦To ・・・・・・・・・・・・・・・
...(1) Formula Tkl -m X T6+Ts (where m is an integer)...(2) Formula Tkz -2Td + To
・・・・・・・・・・・・・・・・・・ (3) Formula T
d=nT+1+△t・・・・・・・・・・・・・・・
... (4) Equation m=2n+1 (where m and n are integers) (5) Equation notation Equation (2), (3), (4), (
5) Calculating the sampling timing difference Δ from equation (
6) The value of Eq. Therefore, Tk, -Tk to (2n+1)To+Ts= 2 (nT,)+Δt)+
T.

In order to make △t zero using the equation φ), Cζ is measured at the slave station and takes one time T.
It is only necessary to adjust the sampling timing on the slave side by the value of s of 1. However, if the transmission timing of the slave station is shifted by this value of 1/2T3.

Since the transmission timing of data S2 being sent from the slave station to the master station changes, the arrival timing of data S2 on the master station side also changes, making it impossible to transmit the flag FO indicating "timing match". Therefore, in the slave station, the data transmission timing from the slave station to the master station remains unchanged, and the value t of 1/2Ts
Control is performed to shift the internal sampling timing of the slave station.

That is, the data transmission timing and sampling timing are the same at the master station, but the data transmission timing and sampling timing are different at the slave station.

However, since the original purpose of 1 is to completely match and synchronize the sampling timing between the master station and the slave station, there is no problem even if the transmission timing and sampling timing of the slave station do not match.

Next, control is performed to match the sampling numbers of the master station and the slave station. Fig. 1 also shows the state after the above-mentioned sampling timing difference is controlled to zero.
The master station receives the data S1 of the slave station's specific sampling number "0", and at the immediately following sampling timing lO'
A flag Fm indicating "S1 reception" is loaded and transmitted to the slave station. When the slave station receives this flag Fm, it memorizes the sampling number RA "7" of its own station at this time, and also carries the flag Fm and stores the sampling number SA "10" of the data transmitted from the master station. Acknowledge.

At slave station D sampling number "7", flag F from master station
The arrival of m means (2) Equation 9 (3) Equation (4)
From formula E, the transmission delay time Td between the master station and slave station is Td-
The fact that the sampling number of the data transmitted after loading Ftn is "10" means that the sampling number of the slave station is ahead (lags) by 6 compared to that of the master station. This state can be expressed mathematically as
The formula (7) is obtained. ε indicates the number of delays in the sampling number of the master station with respect to the slave station.

RA+1 tmsh-□・・・・・・・・・・・・In the example of equation (7) in Figure 1, ε: 6 from SAAlO2RA rule 7,
This shows that the slave station is behind the master station by six sample numbers. (7) In the formula, SA is an integer value between θ and 11,
臥 takes an odd value between 1 and 11. FIG. 3 shows the relationship between the ε value and the sampling number between the master station and the slave station.

The slave station can know the sampling number difference between it and the master station by the ε value, and changes its own sampling number to eliminate the sampling number difference with the partner station.

In the example of FIG. 2, sampling number 8 is advanced by 6 samplings to become sampling number 2. The method of change is to add the ε value to the sampling number of the slave station and use the remainder only when it exceeds 12, and otherwise use the same value as the sampling number of the new slave station.

In the embodiment described in h, the sampling timing and sampling number were controlled in the slave station, but on the contrary, by performing the same calculations and control in the main station, it was possible to achieve the same results as in the earth and mud embodiment. It has the effect of

In the embodiment described above, the sampling timing and sampling number were controlled in the slave station, but in order to match the sampling timing in the master station, slave station, and both stations, f
The sampling timing can be measured by adjusting the phase of the own station's transmission timing (control to change it) to match the data reception timing from the slave station and the transmission timing of the master station σ.About synchronization of sampling numbers is controlled by either the master station or the slave station.
Although it is necessary to carry out eight operations, the same effect as in the above embodiment can be obtained no matter which one is executed.

Furthermore, in the above embodiment, the flag information is returned at the timing of the main station's first transmission immediately after receiving the data of a specific sampling number, but the flag information is returned after a fixed sampling interval after receiving the data or after a fixed delay that does not change. For example, no matter how long the reply is sent, the same effect as in the above embodiment can be obtained.

In the above embodiment, the case between two stations, the master station and the slave station, was explained with concern, but the case between three or more stations may also be used. Synchronization is achieved using the same control. Next, the remaining 1 station and the above synchronized 2
If synchronization is achieved with one of the stations using the same control as in the embodiment, the same effects as in the embodiment described above can be obtained.

In addition, the above embodiment describes the case of a protective relay device, but it may also be a seismometer, a standard clock, etc. that requires synchronization between points with a certain distance. be effective.

Furthermore, in the embodiment described above, the flag information includes both the flag information indicating that a specific sampling number has been received and the flag information indicating the temporal coincidence between the data arrival timing and the local station transmission timing. A similar effect can be achieved by separating the meaning into separate flag information.

〔Effect of the invention〕

As described above, according to the present invention Cζ, when a specific sampling number is received from the slave station to the master station, matching control of sampling timing can be performed using only the single bit information sent back to the other station. The time data to be measured can also be measured using only the time data 1Jif7) of only one slave station.

Therefore, the slave station only needs to have hardware for the amount of time measurement counter l.

The main station only needs to check whether the reception timing and transmission timing match, and this also requires extremely simple hardware, making it possible to construct an inexpensive and highly reliable system. Furthermore, since there is no need to transmit time data, there is an effect that the transmission efficiency can be increased.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the principle of a sampling signal synchronization method according to an embodiment of the present invention, and Fig. 2 is an explanatory diagram showing the principle of a sampling signal synchronization method according to an embodiment of the present invention. A time chart showing the transmitted and received signals when the reception timing at the master station and the transmission timing match. Figure 3 is a diagram showing the sampling number difference and the sampling number relationship between the master station and the slave station. Figure 4 is a diagram showing the conventional FIG. 2 is an explanatory diagram showing the principle of a sampling signal synchronization method.

Claims (1)

[Claims] In a transmission method in which data is sent and received between stations A and B in the same cyclic transmission format with sampling numbers added at regular intervals using opposing transmission paths, the period T in which the same sampling number occurs is When the transmission delay time of each transmission delay time is greater than twice, station A transmits a signal with a specific sampling number on the transmission format at a fixed period, and station B, which is the other station, transmits a signal with the specific sampling number from station A. Compares the timing of the arrival of the signal with the transmission timing of the own station (station B), and notifies the match or mismatch, and sends flag information indicating that the signal of the specific sampling number has been received. Immediately after receiving the signal of the specific sampling number mentioned above, or after a certain time delay, it is sent back at the transmission timing of its own station (B station), and based on the above flag information returned from B station, A station sends a reply to the other party's signal. The transmission timing of the own station (A station) is changed and adjusted until the flag information that indicates "timing match" is returned from the station B, and the data arrival timing and the transmission timing of the B station are adjusted at the B station. In a state where the times match, on the A station side, the time from the most recent transmission timing of A station to the reception of the above flag information is measured, and when the A station receives the above flag information, the own station From the sampling number indicating the transmission timing, the sampling number of the partner station that sent the flag information, and the measurement time of the one quantity measured above, calculate the timing difference at which the same sampling number occurs between the own station and the partner station, and calculate the timing difference between the two stations. A sampling signal synchronization method characterized by adjusting the sampling timing of station A in order to make the difference "0".