Firmware Architecture - GE D90 Plus Instruction Manual

PRODUCT DESCRIPTION

Firmware architecture

4
Plus
The D90 is a sub-cycle distance protection and advanced automation controller that is
organized into six functions.
• Protection
• Automation
• Metering
• Digital fault recorder (DFR)
• Equipment manager
• Front panel interface
These functions operate independently from one another. Each function has its own
configuration settings and generates it own output signals. All functions share the
hardware and the communications facilities within the device.
The protection function contains the necessary elements required to detect faults in the
power system and send tripping signals to isolate the fault. This is the primary sub-system
for many users. The protection function also has its own dedicated FlexLogic engine that
runs at the same scan rate as the protection (16 times per power system cycle). Protection
FlexLogic is used to create custom logic schemes for protection purposes.
The automation function is divided into two major sub-groupings: control schemes and
automation logic. Control schemes are hard-coded general purpose schemes responsible
for automatic control within the substation. These include breaker and disconnect switch
control, interlocking, and synchrocheck. Automation logic is intended for development of
custom or advanced automatic schemes where the user requires a level of functionality
beyond that provided in the hard-coded schemes. Automation logic generally requires a
lower execution rate than protection logic but with expanded functionality and lines of
logic.
The metering function generates a range of real-time power system measurements,
including voltage, current, frequency, complex power, and energy. It also incorporates a
data logger that provides historical recording of selected metering quantities and includes
statistical (maximum, minimum, and average) and alarm capabilities. The metering
function also provides synchrophasor capabilities in accordance with IEEE C37.118-2005.
The digital fault recorder (DFR) function incorporates transient recorder, disturbance
recorder, and fault report capabilities. The transient recorder is intended to capture short
events, such as a fault at a high sampling rate (up to 256 samples per cycle). The
disturbance recorder captures longer events, such as a power swing at a lower sampling
rate. The channel assignments and triggering of these features can be independently
configured. The fault report facility provides a comprehensive record of the key
measurements associated with an event, including fault type, fault location, pre-fault and
post-fault quantities, and clearing time.
The equipment manager function monitors important parameters of the station battery
under normal operation and can be used to detect incipient failures.
Despite their logical separation, signals can be exchanged among these functions. For
instance, it is useful for the digital fault recorder to record the output of protection
functions. Consequently, a pre-determined set of signals is available as inputs to each
function. The figure illustrates these signals.
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 2: PRODUCT DESCRIPTION