Real-time power management is a plant manager's secret weapon
Power management system software needs to allow plant managers to control operations to increase system utilization and keep overall costs down
A modern power management system requires new techniques and cutting edge technology to allow electrical power users and producers to be competitive. In light of rising electricity costs and disruptive power outages, it’s imperative for power management system software to put plant managers in control of operations, maintenance, and planning of the electrical system – resulting in optimum system utilization, lower costs, and financial stability.
This new breed of model-based power management application should have the capability to integrate an active blueprint of the system including system topology, engineering parameters and other pertinent information with time-synchronized-data acquired for the purpose of depicting the actual operation of the system.
Advanced applications and simulation engines should allow improved situational awareness, look-ahead proactive approach and improved decision making for operators under emergency conditions. The same power management system should therefore serve operators, engineers, planners and managers by providing pertinent information to various levels within the enterprise. The information should be available to engineers and planners via desktop clients while the operators and managers can also rely on thin clients.
One of the key advantages of utilizing a model based power management system is maintaining consistency of the network model across engineering, planning, protection and operations department. Traditionally, real-time systems use power system models that differ considerably in detail and structure from the models used for offline studies. Linkages between the different models are typically not maintained, and the different models often have incompatible data formats.
Planning and operating decisions are based on the results of power system simulations. Optimistic models can result in under-investment or unsafe operating conditions while pessimistic models can also lead to unnecessary capital investment, thereby increasing the cost of electric power. Realistic models are needed for ensuring reliable and economic power system operation.
Hence it is a very crucial phase to verify & validate (V&V) the network model with real-time and/or archived data and prepare a benchmarked model for:
- State estimation / Monitoring
- Predictive simulation “what-if” analysis
- Forensic “root cause & effects” analysis
- Proactive contingency analysis & Remedial Actions
This can be achieved by utilizing a power management system that offers traditional simulation analysis tools on the same platform as the real-time operations tools. Doing so avoids the necessity to rebuild and maintain separate network models across various departments.
System monitoring is the base function for any power management software. In addition, seamless integration with metering devices, data acquisition, and archiving systems are essential to monitoring software. Real-time or snapshot data are linked to an online model of the system for proper presentation of actual operating status.
All this information should be accessible to the system operator through advance man-machine interfaces such as an interactive one-line diagram that provides logical system-wide view.
The next step is to process the telemetry data and determine the missing or faulty meter values using advance techniques such as State and Load Estimator (SLE).
The system should also be able to compensate for absence of physical meters by providing virtual metering of devices. Standard power monitoring systems are inadequate since they can only monitor based on the “eyes” you provide in the form of digital measurement devices. These devices can cost $5,000/unit depending upon their complexity and it quickly becomes prohibitively costly to install such meters at every location.
Virtual meters not only improve situational awareness, but also provide a means to alarm equipment (especially low-voltage) that is not visible to a traditional power monitoring system. A model-based power management system uses existing metering devices and makes estimates for the portions of the system that is not monitored.
A chemical plant avoided installation of five such meters and relied on estimated data for non-critical areas and realized a savings of $20,000 in capital expenditure immediately and enjoyed the supplementary benefit of complete system visibility and information for every load in the system.
Dashboards and thin clients
Energy dashboards summarize and record alarm conditions in case of unusual activity and provide continuous visual monitoring of user-selected parameters in any mode of operation. This provision would allow early detection and display of problems before a critical failure takes place. A modern power management system should not only provide monitored data via thin client, but also offer the following key advantages:
- Utilize the same electrical model as the desktop client and the offline planning model without having to recreate or maintain copies of the model. This results in significant time and cost savings when building Human-Machine Interfaces (HMIs). Traditional power monitoring systems are inexpensive to purchase, but take up a significant amount of time, resources and engineering cost to setup the HMIs. Extensive engineering man-hours are also spent modifying the existing HMIs. While in a model based power management system, the offline study model can be simply transitioned and connected with real-time data.
- Ability for the operator to recall and run pre-defined scenarios and get a simple decision (go / no go) especially when he/she is facing emergency conditions. Information overload will not only slow down every decision, it may invariably lead to complete system shutdown.
System engineers and operators must have instant access to energy information and analysis tools that allow them to predict an outcome before actions are taken on the system.
In order to design, operate, and maintain a power system, one must first understand its behavior. The operator must have firsthand experience with the system under various operating conditions to effectively react to changes. This will avoid the inadvertent plant outage caused by human error and equipment overload. The cost of an unplanned outage can be staggering (See Figure 1 at top.)
For industrial and generation facilities that utilize power system analysis applications, the ability to perform system studies and simulate “What If” scenarios using real-time operating data on demand is of the essence. For example, using real-time data, the system operator could iteratively simulate the impact of starting a large motor without actually starting the motor.
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