ABB 615 series Technical Manual page 292

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Protection functions

GUID-93025A7F-12BE-4ACD-8BD3-C144CB73F65A-ANSI V2 EN

Functional module diagram

Level detector

The measured phase currents are compared to the set Pickup value. The TRMS values of

the phase currents are considered for the level detection. The timer module is enabled if

at least two of the measured phase currents exceed the set Pickup value.

Once activated, the internal PICKUP signal is activated. The value is available only

through the Monitored data view. The time characteristic is according to DT. When the

operation timer has reached the Trip delay time value, the TRIP output is activated.

When the timer has elapsed but the motor stall condition still exists, the TRIP output

remains active until the phase currents values drop below the Pickup value, that is, until

the stall condition persists. If the drop-off situation occurs while the trip time is still

counting, the reset timer is activated. If the drop-off time exceeds the set Reset delay time,

the operation timer is reset.

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 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 signal activation is preselected with the global

setting Blocking mode.

The Blocking mode setting has three blocking methods. In the "Freeze timers" mode, the

operation timer is frozen to the prevailing value. 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.

1MAC059074-MB A

615 series ANSI

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