Electricity Load Management

    Catapult Software’s OnDemand is a fully automated, direct-control load management system for an electric power distribution business. The system controls sheddable loads to meet preset energy targets. These targets are usually expressed as average load targets over a configurable charge period, commonly 30 minutes. Separate targets are supported for each connection point between the transmission and distribution networks. Sophisticated load-prediction algorithms use variable combinations of historic data, current load data and ambient conditions. OnDemand also maintains a model of the load currently available to be shed or restored for every controllable load in the system. This comprehensive and accurate picture of load enables OnDemand to satisfy both average and instantaneous connection-point targets, plus guaranteed on and off times, priorities and load cycling requirements for each of the many controllable loads in the system.

    OnDemand is designed to be integrated entirely within your SCADA system, accessing metering and other data already collected by the SCADA, and using the load shed/restore control capability of the SCADA to satisfy load management objectives. This integration is complete: The interface to OnDemand is the SCADA GUI. All OnDemand parameters and data are displayed and edited using the standard SCADA services. SCADA systems that OnDemand has been totally integrated are listed at the end of this document.

Direct control load management

    The OnDemand software system automates direct load control for an electricity distribution business. It operates as an integral part of SCADA, using SCADA I/O services to monitor and control loads. These may be any loads the distribution business can directly and remotely control such as domestic hot water, irrigation schemes, cool stores or other switchable loads.
    The primary objective of OnDemand is to meet system energy targets, without exceeding any instantaneous sub-region limits. This is achieved by predicting upcoming demand and then directly controlling loads as required to avoid target violations

Managing all point of delivery into the network

    OnDemand separately manages each connection point between the transmission and distribution networks. At each point it manages controllable load to meet both energy targets and equipment loading constraints. Energy targets are expressed as average demand interval, commonly 30 minutes.

Equipment constraints

    OnDemand can also ensure that instantaneous demand constraint limits are met for sub-regions within each delivery point.

Load models

    OnDemand maintains a model of the load currently available to be shed or restored for every controllable load in the system. This comprehensive and accurate picture of load enables OnDemand to satisfy both energy and instantaneous demand targets at connection points,plus guaranteed on and off times, priorities and load cycling requirements for each of the controllable loads in the system.

Demand predictions

    To provide effective and efficient control, OnDemand needs to have accurate records of both energy consumed to date, and predicted system demand for the remainder of the demand interval. OnDemand utilizes sophisticated prediction algorithms to determine the future load profile. The prediction process uses a combination of historic and current load data, data and time information, and historic and current environmental conditions.

Prediction

    Sophisticated load-prediction algorithms use variable combinations of historic and current load data plus ambient conditions, tuned by operator experience. Prediction capabilities for each point of delivery include:

•  Average load for the current interval
•  Average load for the next demand interval
•  Maximum daily instantaneous load
•  Maximum daily instantaneous time
•  Maximum daily alarm state
•  Maximum daily alarm time

Prediction alarms

    Prediction demand profile for the current 24 hours is maintained for every separate load. SCADA alarm and display facilities can be used to report the maximum predicted load and the time of its occurrence for each of these loads.

Display past, present and future load

    Actual demand to date plus prediced demand for the remainder of the day can displayed in a trend chart, with a single seamless pen. Not all SCADA system can utilize this 'past+prsent+future' trend capability.

Prediction without curtailment

    Prediction services are available in a stand-alone "OnDemand Prediction" product for those companies not implementing direct load curtailment.

Manage each point of electricity delivery

    OnDemand provides complete management at each point of delivery of electricity into the distribution network:

• Point of delivery energy targets can be entered by operators or automatically imported from spreadsheets
• Sub-region load constraints enable restriction of instantaneous load in the area to avoid exceeding local equipment maximums
• OnDemand can provide both prediction and automated control in a region, or prediction only, advising operators of recommended controls

Simplify management of large systems

    A load 'channel' is a logical grouping of many individual loads into a single load management entity. For example hundreds of individual domestic hot water cylinders are commonly grouped into a single load management 'channel', greatly simplifying management of the network. Each load channel is separately prioritized, controlled and managed. Channel features include:

• Definable priority levels
• Definable time constraints
• Definable load patterns
• Definable plant delays
• Manual or automatic control
• Definable guaranteed On Times

Audit tracking

    All OnDemand decisions and calculations can be recorded in an audit file. This standard text file can be archived and viewed as required.
    OnDemand can also add messages into the standard SCADA event system. This is restricted to important system information and operational advice, avoiding overload of the SCADA event system.

Complete SCADA integration

    OnDemand is entirely integrated within it's host SCADA system. There is no seperate hardware to install, database to manage, nor any new GUI to learn:

• OnDemand parameters are stored in the SCADA database
• Data required by OnDemand is collected by SCADA and accessed from the SCADA database
• SCADA control (output) capability is used by OnDemand to control load channels to meet load management objectives
• The SCADA GUI becomes OnDmand's GUI