Page 23 - CARILEC CE Industry Journal_Oct_2019

THE PATH TO A FLEXIBLE SYSTEM Utilities now have to manage demand, and the supply
from various generation sources, at a distribution level in
real-time. Demand may increase, and more or different
Utilities have used control techniques to manage the energy sources may become available, on a variable
distribution network safely and to reduce interruption basis. Equally they may not be available because the
times to consumers. The majority of traditional network network is constrained and cannot support any more
automation schemes using SCADA, as well as the more generation. The distribution network has to be managed
recent FDIR schemes have been implemented with the in a similar way to the transmission. Collectively these
purpose of restoring supply after a fault has occurred. applications are termed Active Network Management
However, a complementary smart approach is to manage (ANM) or in some markets Distributed Energy Resource
the distribution network assets and distributed energy Management Systems (DERMS), as illustrated in figure 2.
resources to prevent the occurrence of entering into
abnormal running arrangements and avoiding the
network from operating above safe operational limits.
This may be achieved through functionality such as timed MAXIMIZING HOSTING CAPACITY
connections, operational tripping and constraint
management. As utilities progress from timed The conventional approaches to integration of DER have
connections through to constraint management the been to plan for the maximum secure hosting capacity,
system does become more complex. with fast acting protection tripping off the generation in
the event of any network outages. This ‘fit & forget’
The role of network system operator approach limits additional DER due to the costs of
reinforcing the network, and also limits the hosting
The role of network system operators is to balance supply capacity as it only considered the worst case conditions.
and demand in real-time while maintaining stability,
quality of supply and availability of power. To deal with
complexities of measuring, monitoring, control and
management of power and energy across networks,
multiple control room systems have evolved. Network
and system operators rely on systems such as SCADA,
EMS, DMS, ADMS, GIS, and OMS and more. Control
room systems often have substation level sub-systems
such as SAS and SCS. For energy retail and wholesale
operations another family of systems evolved such as
advanced metering infrastructure (AMI) and automated
meter reading (AMR).
The new role of the network system operator
Figure 3 - Maximizing Hosting Capacity
Whereas mainland Distribution Network Operators are
now becoming a Distribution System Operator, Caribbean
network operators already provide electric power These existing approaches avoid “constraints” and the
generation, transmission and distribution services. possible curtailment of DER. This leaves reserve or latent
However, with increased penetration of renewables and capacity in the network for the majority of the time, as
other DER, the development of new control room shown in figure 3. To release this latent capacity, ANM
applications for ‘distribution’ system operators and DER systems are used to monitor the real time capacity of the
operators has evolved. grid and reduce distributed generation output only when
the grid is actually under stress. Two constraint
management schemes that help manage this capacity;
Timed Connections, and Centralized ANM shall be
considered.

Figure 2 - Managing capacity
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