MiCOM P921/P922/P923 - Schneider - error

Technical GuideP92x/EN FT/H42User GuideMiCOM P921/P922/P923 Page 37/702.6 ProtectionsPROTECTION G1To gain access to the “PROTECTION” menu from the default display, press followed by until the desired submenu header (Protection group 1 or protectiongroup 2) is displayed..The accessible submenus are then indicated below:[27]UNDERVOLTAGE [59]OVERVOLTAGE [59N]RESIDUAL O/V [47] NEG SEQ O/V (1) [27D] POS SEQ U/V (1) [81] FREQUENCY (1) [81R]FREQ CHANGE DELTA U / DELTA T (2) OF RATE (2) (1) P922 and P923(2) P923 only2.6.1 Undervoltage protectionThis function can be configured according to the connection scheme of the VTs:phase-phase protection (delta connection) or phase-neutral protection (starconnection).The configuration of this function can also be done in order to detect an absence ofvoltage for all phases:• Undervoltage condition for one of the 3 phases (select OR for the consideredstage),• Undervoltage condition for all 3 phases (select AND for the considered stage).The settings of the voltage thresholds are done in secondary values.The relay will trip according to an inverse characteristic or a definite timecharacteristic for the first stage and according to a definite time characteristic for thesecond and third stages.The inverse characteristic is given by the following formula:t = K / ( 1-M )Where,K = Time Multiplier Settingt = operating time in secondsM = Applied input voltage / Relay setting voltage (Vs).To gain access to the “[27] UNDERVOLTAGE” submenu from the “PROTECTIONgroup” menu, press .PROTECTION G1 (G2)[27] UNDERVOLTAGEHeading of the protection menu (group 1 or group 2). To gainaccess to the menu from the default display press followedby or until the menu is displayed.Heading of the undervoltage submenu.