Page 9 - GuardII+ Series 4208 Platform PD User Manual

Introduction

NOTE:
A GuardII+ PD card is a component of larger system, and requires a
GuardII+ Series 4208 Platform to function. GuardII+ PD cards are not
compatible with original GuardII monitors and original GuardII PD cards
are not compatible with GuardII+ monitors.

NOTE:
A GuardII+ monitor can only support one PD card.

1. Introduction

1.1. Application

The GuardII+ PD card is an optional add-on for the GuardII+ continuous on-line monitor
that is used to detect partial discharge (PD) activity on motors and generators. The system is
sensitive to the most common stator winding failure mechanisms; for example, overheating,
contamination and loose windings. This allows plant personnel to plan corrective action if the
GuardII+ monitor detects problems. Several methods to reduce the risk of false indications
have been built into the system.

A power frequency synchronization signal is required for the GuardII+ PD card to function.
When EMCs are used, enough power frequency signal is coupled to the PD card through the
EMCs to provide this synchronization. When SSC’s are used, an external reference source
is required; the SSC does not produce any synchronization signal. The phase angle between
the phase under test and the synchronization signal must be known

The GuardII+ monitor is mounted outside of the generator near the sensor Termination
Box. Coaxial cables connect the Termination Box to the PD card.
NOTE:
This manual only contains detailed information on the GuardII+ PD cards;
for details concerning the GuardII+ Series 4208 Platform, a different
monitoring technology or sensor installations, refer to the Manuals for
those components.

1.2. Features
• Customizable for number of inputs and type of PD sensors

• Built-in outputs for running measurements to test hardware functionality
• Triggers that store measurements based on Operating Conditions and specific PD
patterns

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