ABB RELION 620 Series Technical Manual page 565

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1MAC504801-IB E

620 series ANSI

Technical Manual

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 signal activation is preselected with the global

setting Blocking mode.

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

trip 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 function block can be used for any general analog signal protection, either

underprotection or overprotection. The setting range is wide, allowing various protection

schemes for the function. Thus, the absolute hysteresis can be set to a value that suits the

application.

The temperature protection using the RTD sensors can be done using the function block.

The measured temperature can be fed from the RTD sensor to the function input that

detects too high temperatures in the motor bearings or windings, for example. When the

ENA_ADD input is enabled, the threshold value of the internal comparator is the sum of the

Start value Add and Start value settings. This allows a temporal increase or decrease of the

level detector depending on the sign and value of the Start value Add setting, for example,

when the emergency start is activated. If, for example, Start value is 100, Start value Add

is 20 and the ENA_ADD input is active, the input signal needs to rise above 120 before

38 Input signals

Protection-related functions

Analogue input value

Block signal for activating the blocking mode

Enable pickup added

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