Timer Characteristics - ABB 615 series Technical Manual

1MAC059074-MB A
4.5.2.5
4.5.2.6
615 series ANSI
Technical Manual
The Timer calculates the pickup duration value PICKUP_DUR, which indicates the
percentage ratio of the pickup situation and the set trip time. The value is available in the
Monitored data view.
Blocking logic
There are three operation modes in the blocking function. The operation modes are
controlled by the BLOCK input and the global setting in Configuration/System/Blocking
mode which selects the blocking mode. The BLOCK input can be controlled by a binary
input, a horizontal communication input or an internal signal of the protection relay's
program. The influence of the BLOCK input signal activation is preselected with the global
Blocking mode setting.
The Blocking mode setting has three blocking methods. In the "Freeze timers" mode, the
operation timer is frozen to the prevailing value, but the TRIP output is not deactivated
when blocking is activated. In the "Block all" mode, the whole function is blocked and the
Timers are reset. In the "Block TRIP output" mode, the function operates normally but the
TRIP output is not activated.
The "Freeze timers" mode of blocking has no effect during the "Inverse
reset" mode.

Timer characteristics

The operating curve types supported by 27 are:
Table 522: Supported IDMT operate curve types
Operating curve type
(5) ANSI Def. Time
(15) IEC Def. Time
(21) Inv. Curve A
(22) Inv. Curve B
(23) Programmable
Application
27 is applied to power system elements, such as generators, transformers, motors and
power lines, to detect low voltage conditions. Low voltage conditions are caused by
abnormal operation or a fault in the power system. 27 can be used in combination with
overcurrent protections. Other applications are the detection of a no-voltage condition, for
example before the energization of a high voltage line, or an automatic breaker trip in case
Section 4
Protection functions
623