Chapter 1 - Introduction
3
PRODUCT SCOPE
The P543 and P545 devices have been designed for current differential protection of overhead line and cable
applications. Version M85 of P543 and P545 have been designed for both solidly grounded systems and Petersen
Coil grounded systems. The products within this range interface readily with the longitudinal (end-end)
communications channel between line terminals. The P543 and P545 devices are for single circuit breaker
applications.
The devices include high-speed current differential unit protection with optional high performance sub-cycle
distance protection, including phase segregated aided directional earth fault protection as well as in-zone
transformer differential protection and 4-shot phase-segregated Autoreclose protection. The P545 provides more
I/O and is housed in a larger case than the P543. The differences between the model variants are summarised in
the table below:
Feature/Variant
Number of CT Inputs
Number of VT inputs
Opto-coupled digital inputs
Standard relay output contacts
High speed high break output contacts
The M85 version of these devices provide additional functionality, which allow them to be used for cross-country
faults in Petersen Coil earthed systems. To supplement this requirement, in addition it provides transient earth
fault detection, a sixth protection zone, enhanced power swing detection functionality and a VT input for
measuring the neutral voltage.
3.1
PRODUCT VERSIONS
This product is a special version from the P40L family. This diagram shows from which version this product has
evolved.
6
P543 model A
P543 model S
5
5
4
4
16
16
14
7
4
P545 model A
P545 model N
5
5
4
4
24
32
32
32
P543i/P545i
P545 model S
5
4
24
16
8
P54x1i-TM-EN-1