Electric Energy T&D - Index

Electric Energy T&D - EE Magazine March / April 2009 - Index

2. Integrated DMS Applications Improve the Outage Management Process
The integration of DMS applications in the OMS has proven to improve
outage performance. For example, a fault location algorithm uses the
as-operated electric network model, including the location of open
switches, along with an electrical model of the distribution system
with lengths and impedances of conductor segments, to estimate
fault location. The DMS Fault Location functionality therefore uses
the electrical DMS model, but ultimately improves the OMS process.
The experience of Progress Energy Carolinas with the ABB Fault
Location application shows a significant reduction in SAIDI over the
6 years since the application has been in operation.
Similarly, a Restoration Switching Analysis application evaluates the
possible isolation and restoration switching actions that can be done
upon occurrence of a permanent fault. The application executes an
unbalanced load flow to determine overloaded lines and low-voltage
violations for each switching action, and the operator is provided with
a listing of recommended switching actions. Again, the functionality
utilizes the DMS model of the system, but improves the Outage
Management process and reduces CAIDI and SAIDI.
3. DMS/OMS Integration Improves Coordination of Planned and Unplanned
Work
Distribution systems are dynamic in nature, with changes occurring
on a daily basis due to both planned work and outage restoration. If a
safe and efficient operation of the system is to be achieved, then it is
critical to ensure that the current state of the network is continuously
maintained and made available to those working on planned and
unplanned work. This includes operators, dispatchers, persons
responsible for switching requests and switching plans, field crews,
engineering, and others who require an accurate representation of the
system state.
Temporary network changes such as line cuts and jumpers, phase
jumpers, switch operations, protective device operations, grounding
tags, safety, warning, and information tags, and temporary generators
should be represented. This is easiest if a single model is used for
the DMS and OMS.
With DMS and OMS working with the same operational model of the
distribution system, circuit analysis can be fully functional considering
temporary changes. This includes circuit tracing, trouble call and
outage analysis, safety interlocks, loop and parallel source detection,
fault location and load flow. The result is a more comprehensive and
accurate understanding of system conditions at any moment in time.
4. DMS/OMS Integration Reduces Data Maintenance Efforts
Many distribution organizations maintain and make planned updates
to the network model in their Geographic Information System (GIS).
Since DMS and OMS both require a connectivity model of the
distribution system, data maintenance processes are simplified if the
DMS and OMS are operating from the same model. The result is one
set of processes for managing the network model, and one process for
the incremental update to the DMS/OMS model instead of two.
Integrated SCADA/DMS/OMS: Increasing Distribution Operations Efficiency
Integration of SCADA and DMS/OMS
Integration of DMS/OMS with SCADA is an increasing trend. While
the inclusion of SCADA “breaker-open” operations in OMS have long
been used for outage detection, recent business challenges have
driven a more comprehensive integration between the two systems.
Available functionality now includes the transfer of status/analog
points from SCADA to the DMS/OMS; the sending of supervisory
control and manual override commands from the DMS/OMS to the
SCADA; an integrated user interface running on the same operator
console, and integrated single sign-on for users.
The benefits of integrating Scada with dmS/OmS include:
• Improved operations by close integration of DMS applications with
distribution SCADA
• Increased operator efficiency with one system, eliminating the
need to go to multiple systems with potentially different data
• Integrated security analysis for substation and circuit operations to
check for tags in one area affecting operations in the other
• Streamlined login and authority management within one system
• One network model for OMS and DMS analysis
• Consolidated system support for DMS/OMS and Distribution
SCADA
• Simplified data engineering via coordination of SCADA point and
GIS data changes
Integration of SCADA and DMS/OMS can be between systems of the
same vendor, or between different vendors, using a protocol such as
ICCP (Inter-Control Center Communications Protocol). Using systems
from the same vendor typically results in increased functionality and
can reduce the need for data engineering in the systems.
Integrated Distribution Operations Center
figure 3 depicts the architecture for a fully integrated distribution
operations center. The integrated DMS/OMS system model is initially
created using a one-time data load from the GIS. Periodic updates to
the DMS/OMS model is then performed using an incremental update
process from the GIS. Since the DMS and OMS use the same network
model, it is only necessary to have a single update process.
March-April 2009 Issue I
figure 2 - DMS – Integrated SCADA/DMS/OMS Architecture
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