Sepam - HV/MV Protection and control units (ENG) - Trinet

Time tagging of events (cont’d)Other processing operationsFiltering of oscillating dataAs protection against abnormally frequent statuschanges, Sepam 2000 filters oscillating data in orderto avoid saturation of the time tagging communicationfunction. A data item is declared to be oscillating whenit changes status more than 10 +3 times in 2 seconds.Once this occurs, no further status change eventsare generated. A time tagged event “appearanceof oscillating channel” is transmitted. The data itembecomes non-oscillating again when it remains stablefor at least 10 seconds. When this occurs, a timetagged event: “disappearance of oscillating channel”is transmitted. In order to guarantee data consistencyin the monitoring and control system, a “theoretical”status change is generated, with the same dateand time, to indicate the stabilized statusof the channel which has ceased to oscillate,whatever its previous status.Data synthesisA synthesis of Sepam 2000 data is produced by meansof the Sepam status check-word. Status changes ofcertain bits in the words are time tagged. The meaningof each of the bits in the Sepam 2000 check-wordis given in the chapter entitled “data addressesand encoding” (see format X).The time tagging function processes the followingstatus changes:c presence of a partial fault in Sepam 2000,c presence of a major fault in Sepam 2000,c setting terminal: in parameter setting mode / inreading mode,c Sepam 2000: incorrect time / correct time,c Sepam 2000: non-synchronous. / synchronous,c Sepam 2000: in data loss status / not in data lossstatus (refer to t he next section entitled “descriptionof event coding”.Installation of the time tagging functionEach time the communication system is initialized(energizing of Sepam 2000),the events are generated in the following order:c appearance of “data loss”,c appearance of “incorrect time”,c appearance of “non-synchronous”,c disappearance of “data loss”.The function is initialized with the current valuesof the KTS and logical input status without creatingany events related to these data. After the initializationphase, event detection is activated. It can only beinterrupted by saturation of the internal event storagequeue or by the presence of a major fault inSepam 2000.Date and timeAn absolute date and time are generated internally by Sepam 2000, comprising thefollowing information: Year : Month : Day : Hour : minute : millisecond. Sepam 2000’sinternal clock is not saved; it needs to be time-set via the Jbus communicationnetwork each time the Sepam 2000 is energized.The time that is tagged on events is encoded in 8 bytes as follows:b15 b14 b13 b12 b11 b10 b09 b08 b07 b06 b05 b04 b03 b02 b01 b00 mot0 0 0 0 0 0 0 0 0 Y Y Y Y Y Y Y word 10 0 0 0 M M M M 0 0 0 D D D D D word 20 0 0 H H H H H 0 0 mn mn mn mn mn mn word 3ms ms ms ms ms ms ms ms ms ms ms ms ms ms ms ms word 4Y - 1 byte for years: 0 to 99 years.The remote monitoring and control system must ensure that the year 00 is greaterthan 99.M - 1 byte for months: varies from 1 to 12.D - 1 byte for days: varies from 1 to 31.H - 1 byte for hours: varies from 0 to 23.mn - 1 byte for minutes: varies from 0 to 59.ms - 2 bytes for milliseconds: varies from 0 to 59999.This information is encoded in binary form. Sepam 2000 is time-set via the Jbus“word writing” function (Jbus function n° 16) at Jbus address 0002 with a mandatory4-word time message.The bits set to “0” in the description above correspond to format fields whichare not used and not generated by Sepam 2000.Since these bits can be transmitted to Sepam 2000 with random values,Sepam 2000 performs the necessary disabling.Sepam 2000 does not check the consistency or validity of the date and timereceived.Synchronization clockA synchronization clock is required for setting the date and time of Sepam 2000.Merlin Gerin has tested the equipment sold by the following suppliers:c SCLE, ref. RH 20000 -B,c Gorgy Timing, ref. RT 300, equipped with the M540 module.20 Jbus/Modbus communication