GE D60 Instruction Manual

Also see for D60: Communications manual Communications guide Instruction manual Instruction manual Instruction manual

Contents

5-310 D60 Line Distance Protection System GE Multilin5.7 CONTROL ELEMENTS 5 SETTINGS5This menu allows selecting and setting up protection signaling of the directional comparison unblocking scheme. Thisscheme is available for single-pole tripping applications and can be used with one, two, or four bit communications chan-nels. Choices of communications channel include remote inputs/outputs and telecommunications interfaces.Generally, this scheme uses an over-reaching zone 2 distance element to compare the direction to a fault at all terminals ofthe line. Ground directional overcurrent functions available in the relay can be used in conjunction with the zone 2 distanceelement to key the scheme and initiate its operation. This increases the coverage for high-resistance faults.The scheme is intended for two or three-terminal applications. As a long reach of the overreaching distance element maybe required for three-terminal applications, transient blocking logic is provided for both distance and ground directionalovercurrent elements. An echo feature is made available to cope with line open conditions.By default the scheme uses the reverse-looking zone 4 distance element to identify reverse faults. Additionally, reverse-looking ground directional overcurrent functions can be used in conjunction with the zone 4.For proper operation of the scheme the zone 2 and 4 phase and ground distance elements must be enabled, configuredand set per rules of distance relaying. The line pickup element should be enabled, configured and set properly to detectline-end-open conditions. If used by this scheme, the selected ground directional overcurrent function(s) must be enabled,configured and set accordingly.In single-pole tripping applications, the scheme uses local fault type identification provided by the phase selector togetherwith information received from the remote terminal. The scheme generates output operands ( DCUB TX1 through DCUB TX4 )that are used to transmit the signal to the remote terminal(s). The directional comparison unblocking scheme was devel-oped for use with frequency shift keying communications channels, though different telecommunications interfaces can beused (for example, digital communication channels utilizing the D60 teleprotection input/outputs).To make the scheme fully operational as a stand-alone feature, the scheme output operands must be configured to inter-face with other relay functions, output contacts in particular. Typically, the output operands should be programmed to initiatea trip, breaker fail, and autoreclose, and drive a user-programmable LED as per the intended application.When used in conjunction with the trip output element, the scheme is pre-configured to initiate trip, breaker fail and autore-close actions.• DCUB BLOCK: This setting allows the user to assign any FlexLogic operand to block the scheme. Contact inputs froma pilot cut-out switch are typically used for this purpose.• DCUB PERMISSIVE ECHO: Enabling this setting will send a permissive echo signal to the remote end(s) under cer-tain conditions (see the logic diagram for details). If set to “Custom”, the echo signal is sent if a condition selected withthe DCUB ECHO COND setting is satisfied. The echo is sent only once and then the echo logic locks out for the timespecified by the ECHO LOCKOUT setting. The duration of the echo pulse is programmable by the ECHO DURATION set-ting. The echo is returned only if no overreaching and reverse protection elements operate.• DCUB ECHO COND: This setting specifies a user-selected echo condition and applies only if the DCUB PERMISSIVEECHO setting is “Custom”.• GND DIR O/C FWD: This setting defines the FlexLogic operand (if any) of a protection element used in addition tozone 2 for identifying faults on the protected line, and thus, for keying the communication channel(s) and initiatingoperation of the scheme (both through the transient blocking logic).Good directional integrity is the key requirement for an over-reaching forward-looking protection element set as GNDDIR O/C FWD. Even though any FlexLogic operand could be set as GND DIR O/C FWD, thereby enabling the user to com-bine responses of various protection elements or to apply extra conditions through FlexLogic equations, this extra sig-MESSAGE DCUB LOG3:OffRange: FlexLogic operandMESSAGE DCUB RX4:OffRange: FlexLogic operandMESSAGE DCUB LOG4:OffRange: FlexLogic operandMESSAGE DCUB SCHEME TARGET:Self-ResetRange: Self-Reset, Latched, DisabledMESSAGE DCUB SCHEME EVENTS:DisabledRange: Disabled, Enabled