Scalable Supervisory Control

eAlarm is an event notification program for the PRISM SCADA software that sends emails for events (or critical alarms that need immediate attention). 

Emails are sent to a user-defined list of up to 20 recipients away from the control center. The user is able to define what is considered a critical alarm or event. Email groups can be defined on the mail server so that multiple people (by job type, location, etc.) may be notified per email address.

Events can include any action which can be stored as an event in the PRISM SCADA database.

• The operation of a switch
• A limit violation of a telemetry point
• A control action by an operator
• Any stored event

ACS takes an Enterprise approach to the input, capture, and dissemination of data in PRISM SCADA through our Historical Data Archive (HDA) system. 

This allows for single point of entry and maintenance for the system in terms of archiving, collection, report building, analyzing, and publishing reports.

Real-time HDA leverages the PRISM SCADA database settings to achieve optimum results. The following feature list is not exhaustive, but demonstrates the breadth of options available to HDA. Each device point in PRISM SCADA can be set to:

• Capture various intervals
• Capture various attributes
• Capture quality data flags
• Filter based on exceptions
• Filter on reporting bands

The HDA subsystem is configured and delivered with processes that automatically archive data offline in a compressed form for efficient storage. Recovering offline storage into the online HDA system is a seamless process that doesn’t interrupt real time operations.

The HDA is generally deployed in a redundant configuration that allows seamless fail-over capabilities, thus minimizing data and access losses. In the event of total loss of the system, the HDA can be readily restored to the last available saved backup. ACS uses various schemes to match the needs to the utility, ranging from cold backups, export/import, and hot backups.

PRISM PlayBack is an optional application that can be utilized by the operator to replay system events and disturbances on the system display as if they were happening in real-time.

PRISM PlayBack provides the system engineer or dispatcher a “bird’s eye view” of the grid, displaying past events in a time-lapse sequence as they actually happened. Much like a media player, operators can control the rate of replay.

PRISM PlayBack has multiple functional uses within the utility:

• Operators can rerun the events of a disturbance for post fault analysis, especially those leading up to the initiating event. This capability is valuable in determining the initial cause of an outage before attempting system restoration.
• Dispatchers can direct field crews to the point of system failure.
• System Planning Engineers can determine the behavior of the system to past recorded major system disturbances, in order to understand and prevent system weaknesses.
• Operations Managers can graphically show officials an easily understandable time-lapse replay of events leading to system disturbances or outages.
• Instructors can understand system dynamics while advancing their handling of major disturbances. PlayBack enables them to develop realistic training scenarios for the system dispatchers, enabling them to more effectively handle similar scenarios in the future.

The Loss Minimization (LM) function is designed to automatically monitor and control individual switchable capacitor banks in real time, in order to minimize overhead feeder losses on the electric grid. 

This is done by reducing reactive power flows while maintaining voltages and power factors within specified limits. The LM function executes periodically at an adjustable time interval, alarming the dispatcher if a switch fails to operate or if the number of switches exceeds a specified maximum over a certain time interval.

The LM function requires a control interface to the PRISM SCADA system via RTUs. Through PRISM SCADA, LM analyzes your distribution network and local conditions. It then switches the individual capacitor banks of each feeder on or off, as needed to minimize losses. Loss minimization can even coordinate its operations with devices that are not controlled by the PRISM SCADA system, like load-tap-changing transformers (LTCs) and capacitor banks.

Short Term Load Forecasting (STLF) utilizes historical load and weather data to forecast the system load. 

It runs automatically at the beginning of each hour and prepares a 168–hour forecast. It can also be executed on demand to provide a 14-day forecast, beginning from the current day. Results obtained at each execution are saved in the real-time database.

The load forecast model is customized for each application. This customization process is comprised of two steps: initialization and maintenance. 

Initialization: The initialization of the model parameters requires a minimum of eight weeks of seed data. STLF then captures new values from the real–time database and saves them for up to one year. The program can also be executed on demand and forecast the load for periods other than the current day.

Maintenance: The model’s internal parameters are automatically adjusted. These adjustments also take into account any changes in system conditions. The model parameters are estimated and adjusted online by using recursive least squares (RLS) techniques. Input of STLF is obtained from and the computed results are saved in historic files and the real-time database. Data can also be stored in an SQL–type databases.

The PRISM SwitchPlan application allows operators and engineers to intuitively create and test switching plans in advance of implementation. 

These “test” plans can be saved by name and manually activated at any time by an operator. They can also be set on a time schedule, or set to initiate by real-time events.

The Switch Plan Editor uses a screen-based editor that allows the user to chain together control actions in series or parallel. Operators can select control devices, tags, or pseudo devices and incorporate sequence interrupts with the mouse as if they were real–time control operations. The system provides visualization of the sequence on the network map.

PRISM Voltage Reduction provides a simple-to-use interface that monitors system conditions to automatically issue voltage reduction commands. 

If the system reaches the target load with the correct time criteria, the program will issue controls to configured voltage control devices. If the load is higher than the set limit, the program will implement the reduction step command for LTC devices if the specified criteria for voltage reduction are met, like user-defined days and time-of-day windows. 

After issuing the control, the system load is checked against the target following a configurable time delay. If the load is still higher than the start limit, the program will implement the load reduction scheme value again. This process continues until reaching the highest tap-changer step. If the subsequent check of the load versus the target is lower than the stop target, the program will then reduce the voltage by one step. This control process will continue until the lowest step is reached. The program will follow this algorithm as long as the logic is armed.