Advanced Distribution Management

Advanced Distribution Management

PRISM DMS combines real-time data acquisition, distribution automation, system analysis and outage management into a true Smart Grid operations system. The PRISM integrated platform provides leading-edge DMS functionality.

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Advanced Distribution Management

PRISM DMS combines real-time data acquisition, distribution automation, system analysis and outage management into a true Smart Grid operations system. The PRISM integrated platform provides leading-edge DMS functionality.

Today’s utilities recognize that customers have different needs, and are acutely aware of the definition of “service reliability” as it pertains to various customer classes. Each of these customer types may require a different type of solution to deliver the expected level of service and power quality. The proliferation of intelligent devices and sensors on the network, and the wide-scale deployment of smart meters also demand an operational system that provides a more holistic and efficient view of the network in real-time.

And the increasing penetration of distributed generation and renewable energy sources presents its own particular set of challenges in the operation of a stable and secure grid. As a result, a unique blend of network modeling, automation and analysis tools is needed—one that transcends the typical distribution SCADA system, and even the traditional idea of distribution management.

ACS offers one of the most advanced and integrated suite of applications available today for distribution network management. Our PRISM advanced DMS, which is based on more than 40 years of experience delivering “mission critical” real-time systems with an open architecture design, features maximum reliability and availability, and offers several key advantages over competing solutions:

  • A fully-integrated single database and network model, using the GIS and available planning data as the source
  • A full suite of advanced applications for visualization, optimization, analysis and operation
  • A completely integrated OMS suite that eliminates the need for costly and complex interfaces for data transfer between different SCADA/DMS/OMS platforms
  • A unified and comprehensive user interface, providing safer and more efficient system control
  • A high-performance real-time engine for all Smart Grid functions, designed to deliver when you need it most
  • A sophisticated simulator platform that enables training of operators and other personnel based on realistic operational scenarios and actual events captured from the operating system

Today’s utilities recognize that customers have different needs, and are acutely aware of the definition of “service reliability” as it pertains to various customer classes. Each of these customer types may require a different type of solution to deliver the expected level of service and power quality. The proliferation of intelligent devices and sensors on the network, and the wide-scale deployment of smart meters also demand an operational system that provides a more holistic and efficient view of the network in real-time.

And the increasing penetration of distributed generation and renewable energy sources presents its own particular set of challenges in the operation of a stable and secure grid. As a result, a unique blend of network modeling, automation and analysis tools is needed—one that transcends the typical distribution SCADA system, and even the traditional idea of distribution management.

ACS offers one of the most advanced and integrated suite of applications available today for distribution network management. Our PRISM advanced DMS, which is based on more than 40 years of experience delivering “mission critical” real-time systems with an open architecture design, features maximum reliability and availability, and offers several key advantages over competing solutions:

  • A fully-integrated single database and network model, using the GIS and available planning data as the source
  • A full suite of advanced applications for visualization, optimization, analysis and operation
  • A completely integrated OMS suite that eliminates the need for costly and complex interfaces for data transfer between different SCADA/DMS/OMS platforms
  • A unified and comprehensive user interface, providing safer and more efficient system control
  • A high-performance real-time engine for all Smart Grid functions, designed to deliver when you need it most
  • A sophisticated simulator platform that enables training of operators and other personnel based on realistic operational scenarios and actual events captured from the operating system

Model Building & Automation

Model Building & Automation

DASmap

Effectively monitoring and managing the distribution system using today’s advanced DMS applications involves a sophisticated electrical model that is more complex than those needed for static, balanced transmission systems.

Real-time power flow and load estimation for an unbalanced, three-phase network must incorporate telemetered data from a variety of sources on the system, along with information from GIS and planning models. Data from sources such as AMI, line sensors, and an array of intelligent controls (breakers, switches, capacitors, regulators, etc.) must all be processed quickly and efficiently to allow the system to react in real-time to changing system conditions.

The system must always be able to accurately represent the state of the network at any given time, as the distribution automation and analysis functions and applications all rely on this network model.

The PRISM DMS also utilizes this model to allow the system dispatcher to perform ad-hoc load flow queries on the system.

To facilitate creation of the distribution model, the PRISM DMS includes DASmap—a powerful GIS import and model creation tool that enables utilities to automatically create the real-time database, system model and operational displays from GIS and engineering model source data.

DASmap even supports incremental updates from the GIS, simplifying the change synchronization process significantly.

Topology Processor

Smart Grid distribution management and distribution automation functions and applications all rely on an accurate model of the state of the network.

Rather than each application determining the network state or network topology, the Topology Processor (TP) calculates the current real-time state to be used by all of the applications as well as by the user interface to colorize the network maps.

Topology processor begins with the static model “as-built”’ connectivity of the network imported from the GIS.

The update from the GIS is the source definition of the connectivity and serves to define the network structure. TP dynamically updates the connectivity by adding the telemetered and manually updated state of the switching devices in the network in order to calculate the ‘topology’. Other applications such as Real-time Redline enable the operator to apply cuts and jumpers which represent temporary of emergency network changes that affect connectivity and therefore topology.

Every system application dynamically adapts to the topology changes in real-time.

Switching order creation applications which generate switching steps in order to meet various objective functions will likewise dynamically adapt to the real-time topology changes.

Topology Processor maintains in real-time the network configuration based on the network connectivity model and dynamic switch statuses.

The function produces the visual and modeled topology of energized and de-energized sections or areas of the distribution system for display and analytical purposes. In addition, it provides visual features such as colorization to distinguish devices that are supplied from different feeders. In the event of a loop created in the distribution network due to switch operations, the function will provide visual indications to highlight all branch devices on the loop and alert the dispatcher.

The feeder network with real-time switch status is calculated to show the current state of the feeder’s topology. Each feeder is colored to show the extent of the circuit.

Fault Detection, Isolation & Restoration

The PRISM Fault detection, isolation and restoration (FDIR) application is designed for automated fault handling on distribution systems with radial or open loop configurations.

The distribution system can consist of feeder sections with three phases, two phases or single phase. It provides the following fundamental control functions:

  • Detect and isolate feeder faults (phase to phase and phase to ground faults)
  • Automatically restore service to the feeder sections upstream of the fault (Primary Restoration)
  • Provide a switching sequence that can be activated by the dispatcher to automatically restore service to the feeder sections downstream of the fault (Secondary Restoration)
  • Provide a switching sequence that can be activated by the dispatcher to automatically connect the de energized feeder sections to available alternative sources if faults appear on the substation side of the feeder breaker.
  • Provide a switching sequence that can be activated by the dispatcher to return the distribution system to its pre fault configuration when previously faulted feeder sections become available for service.
  • The feeder fault detection and isolation function of the FDIR software can be automatically initiated when a feeder breaker trip signal is received. If the breaker has reclosing relays, FDIR will not start execution until it detects subsequent failures of fast reclosing of the feeder breaker to clear the fault.

When the presence of a fault in the feeder is detected, FDIR will identify the fault location by logically analyzing the real time data from the RTUs on the faulted feeder, automatically isolate the faulted feeder section if the related line switches are in remote control mode. After ensuring the fault isolation, FDIR starts to make the primary restoration by re-energizing the feeder sections upstream of the fault. The total time for FDIR to complete all the necessary actions from the moment the fault is detected to the display of feeder re-energization data at the dispatcher console is normally less than 30 seconds.

The function of fault detection and isolation is executed in parallel by FDIR. While single faults occurring simultaneously on several different feeders, they can be handled in a parallel manner and each one can be completed in a few seconds. There is no hard limit on the number of single faults on different feeders occurring simultaneously for FDIR to process at the same time.

Integrated Volt/VAR Control

The primary objective of the Integrated Volt/VAR Control (IVVC) function is to reduce electric feeder losses while minimizing distribution voltage within acceptable operating limits.

The controls used to achieve these objectives are transformer Load Tap Changers (LTCs), substation and feeder capacitor bank controls plus substation and feeder voltage regulators.

Inherently the IVVC function improves energy conservation by reducing load demand in both peak and non-peak periods of operation of the distribution system. The load demand reduction is achieved through minimizing the power loss while maintaining voltage as low as possible without violating distribution voltage constraints. IVVC attains power loss reduction by setting transformer taps and by controlling capacitor banks while feeder voltages are kept above the low limit through a coordinated adjustment of voltage regulators. In order to determine an optimum control strategy without adjusting and readjusting the controls, which interact with each other, a real time three-phase unbalanced distribution Load Flow is used. The Load Flow is used to determine reactive power requirements at various capacitor bank locations as well as for the entire feeder under different iterations of the scenario.

In the process of capacitor bank control, individually operable capacitors on the feeder are identified by topology tracing from a feeder breaker downstream. Feeder loads are estimated to calculate voltage, branch flows, and power factors. The branch flows at capacitor locations are analyzed so that the capacitor banks are sorted in descending order based on their branch reactive power flows. The capacitor with the largest branch reactive power is selected as a control candidate. Its impact on feeder voltages is calculated and checked against the limits. If any constraint is violated, this capacitor bank will be passed over and the next capacitor is processed. Otherwise, a control command is issued to operate this capacitor bank. For example a capacitor needs to be operated if there exists a significant amount of lagging reactive power flow on the feeder breaker. Likewise, it needs to be turned off if there is a large amount of leading reactive power flow on the feeder breaker. The decision can be made through a series of load flow calculations. Finally, to verify if a given capacitor operation violates any voltage constraints, the changes in voltage and power factor are calculated considering the effect of the capacitor operation.

To prevent unbalance switching of a capacitor bank, a verification procedure is followed to check if any switch operation has failed. If so, this capacitor bank will be disabled for future control and an alarm is issued to notify the dispatcher. The above process is repeated until distribution loss is minimized or no capacitor is available for control. The disabled capacitor bank can be re-enabled by the dispatcher once it has been repaired and is ready for use. Defined rules are applied to determine the control action for each capacitor bank, considering maximum number of control operations, minimum on, or minimum off times and an adjustable dead band to prevent unnecessary controls.

Optimization

Optimization

Optimal Capacitor Placement

The Optimal Capacitor Placement (OCP) application is a study mode function that directly connects to the DASdb and the RTDB.

The objective of OCP is to minimize feeder losses while maintaining the capacitor bank voltages and power factors within given limits. The optimal capacitor placement starts from a base case that may be derived from the real time operational condition or a DPF saved case. The user has the capability to specify which capacitor banks can be relocated and which cannot, as well the network buses that can be located with capacitor banks. OCP will then determine both the best locations of the capacitor banks and the optimal on/off status of the capacitor banks needed to meet the specified optimization objective.

All ‘Cuts’ and ‘Jumpers’ placed on the system are marked by an icon on the map for easy identification.

Intelligent Switching

Similar to the Optimal Switch Plan application, the Intelligent Switching (ISW) application provides the capability to generate various switch plans for both planned and unplanned operational situations.

It is expected that these switch plans will be generated on an ad hoc basis by the dispatcher, or generated as scheduled switching operations.

The switch plans generated will observe all violations and criteria as in the OSW application. The primary switching operations to be supported by ISW are:

  • Return-to-Normal: generate a switch plan which will return the system to its normal feeder topology
  • Outage Plan and Scheduling: generate a switch plan which will produce an isolation and restoration plan for outage scheduling and device maintenance
  • Restoration: generate a switch plan which will restore de-energized line segments and loads
  • Cold Start: generate a switch plan which will match the load to the generation
  • In each case whenever it is not possible to restore all un-faulted network section due to violations, the application will provide options that allow consideration of constraint relaxation. When appropriate, the operator can accept a plan based on a selected constraint relaxation.

Optimal Switching

The Optimal Switching (OSW) application is designed to generate recommended switch plans to reconfigure a distribution system in order to meet a specified optimization objective with regards to operation.

Optimal Switching meets specified optimization objectives:

  • Minimum losses: minimize the network power loss for the current or a selected network loading condition by reconfiguring the available switch operations
  • Minimum feeder voltage drops: achieve the flattest voltage profile while maintaining the lowest end-of-line voltage still within operating limits
  • Phase balancing: provide a switching plan to switch individual phases in order to shift the normally open point per phase in order to balance the phases
  • Load Balancing: provide a switching plan to balance the load equally between feeders within the area of analysis

For each objective, the optimal solution is obtained while enforcing the following operational constraints:

  • Respect operating limits of feeder voltages
  • Respect operating limits of branch device currents
  • Operating limits of transformer voltages and currents
  • No interruption of customer loads
  • No loss of customer loads
  • Minimum number of switch operations
  • Minimum number of ineffective switch operations
  • In-rush current for cold load pick up
  • The available switching devices that are studied include feeder line switches, tie-switches, breakers as well as reclosers. The Optimal Switching application also advises the user of any possible loop conditions.

Analysis

Analysis

Distribution Load Flow

The PRISM dispatcher distribution load flow (DLF) is used as a dispatcher query tool for ad-hoc load flow queries, as a planning tool for in-depth network analysis, and as a basis for many advanced distribution analysis / automation applications such as Short Circuit Analysis, Switch Order Optimization, Fault Detection Isolation and Restoration, etc.

The PRISM distribution load flow operates from the same network model as that created by DASmap for all advanced applications.

The PRISM distribution load flow is implemented to compute phase voltage magnitudes for each feeder or network node as well as phase and neutral currents for each branch (line, switch and transformer). The active and reactive losses on each branch, as well as accumulated total and per phase losses for each substation and feeder can also be computed. The PRISM DLF model is implemented utilizing Ybus Gauss solution method that uses sparse Ybus matrix and equivalent current injections to solve distribution network equations. This method has been proven to have rapid convergence rate and less memory usage for distribution networks. The PRISM distribution load flow model applies three-phase sequence model that converts unbalanced three phases into positive, negative and zero sequence phases. After the power flow solution, sequence phases will convert back to three regular phases.

Real-time Study Mode

PRISM DMS provides two different analysis modes: Real-time and Study.

Each mode is independent of the other mode, i.e., changes made by one user in one analysis mode do not affect the other user in study mode. In study mode the user can operate various devices and observe the effect on the system through topology processor or by running a load flow and viewing the results. This is a powerful tool that can be used to study the effects on the system of various system modifications or switching operations. The results of the load flow are colorized and displayed on the operator interface for a quick study, or for more detailed analysis the results can be viewed in a tabular form and exported. Scope of analysis by DPF can be divided into the following categories:

  • Study Scope I: Entire System, where all nodes in all feeders and in all substations are analyzed
  • Study Scope II: Substation, where only the nodes on the feeders of the selected substation are analyzed
  • Study Scope III: A group of substations where only the nodes on the feeders of the substations in the selected group are analyzed
  • Study Scope IV: Feeder, where only the nodes on the selected feeder are analyzed

Short Circuit Analysis

Short Circuit Analysis (SCA) calculates fault current sources to fault points, using programmable criteria for theoretical or reconstructed situations and scenarios. SCA uses the same solution algorithm as Distribution Power Flow (DPF), representing all loads, capacitor banks and short circuit faults as constant impedances. Source voltages behind the internal impedances are calculated based on the DPF solution.

When a fault occurs in an SCA context, the fault impedance will connect from the fault location to ground, or to another phase, depending upon the fault type. The positive–, negative– and zero–sequence networks are created, and the fault current is computed using the DPF.

SCA offers an array of controls and user–programmable conditions:

  • Study scope (study voltage level)
  • Fault locations (substation, feeder, node/device)
  • Faulted phases (any combination of single–, two– and three–phase to phase, and phase to ground)
  • Fault types
  • Fault impedance
  • Zero pre–fault currents

Protection Coordination

Protection Coordination (PCN) provides the system operation engineer and dispatcher a tool to review, edit or analyze the protective device settings.

The protective devices include relays, reclosing relays and fuses. PCN presents to the dispatcher the actual “time-current” curves of protective devices along the feeder for graphical analysis and manipulation based on known fault currents.

Load Estimator

Load Estimation (LE) is a function used to estimate individual loads on a feeder based on load classes, load type, load curve, and load measurements.

  • The Load Class specifies the nature of a load, such as residential, commercial, or industry load. It is used to divide the feeder load into several components, each of them having the same nature or class
  • The Load Type specifies the characteristics of a load in terms of its relationship between its real and reactive power. There are two different load types: conforming and non–conforming. A conforming load uses power factor as a fixed ratio between its real and reactive power; while a non–conforming load defines its real and reactive power by its “load versus time” curves respectively
  • Load measurements are telemetered load values through the SCADA system. They can be either an individual load measurement or a branch load flow measurement

In the Load Estimation function, individual loads on each node are calculated by two methods:

  • Static Load Estimation (SLE): individual loads are identified through the ownership between loads and the feeders carrying those loads
  • Dynamic Load Estimation (DLE): the real–time branch flow measurements are used to adjust load values obtained by static load estimation to produce dynamic load estimation

Visualization

Visualization

GridVu

GridVu is a geographical product which is designed to provide general DMS and OMS incident summary and location information via the internet to utility personnel and to the public.

The information is presented as icons, which are overlaid on a Google map to show their geographic location relative to the geographically viewed network.

GridVu products function on iPad/Tablet/PCs and Smart Phone using an iOS, Android or Windows OS. Browser support for a single code line is provided for platform agnostic browsers: Chrome 10+, Safari 5 +. Check with ACS for information pertaining to use on other browser types/versions.

GridVu network

GridVu network displays outage (Tickets), non-outage (Work Orders) and planned switching overlaid on the near real-time geographical network topology.

GridVu public

GridVu public is a public facing view showing network outages. This view provides normal restoration information relative to the customer, such as number of outages, number of customers affected, restoration time, etc. This data is important in typical storm and outage situations because it informs the public and media of the progress of the utility restoration progress. Color coded outage area polygons are displayed to represent the number of customers that are affected within each political boundary.

ReShape Schematic Generator

PRISM DMS and OMS support both a dynamic geographic based view of the network diagram and a schematic based view for switching, tagging etc.

Both types of views can be drawn using DASmap and linked to the network model for dynamic topology colorization. However, the PRISM system also supports an automatically generated schematic view of a selected feeder using an optional application called ReShape. The advantage of a schematic network diagram versus a geospatial diagram is that the schematic view shows at a glance the entire feeder in its simplest form. Geographic based views are often best used for coordinating with field crews and correlating trouble calls and problems with customer locations, but are of limited value when it comes to switching. The problem arises from the fact that due to the large geographical area covered by most feeders, a zoom level high enough to visualize the entire extent of the feeder is too high to truly “observe” the control devices in order to select the device to perform switching. As a result, dispatchers generally prefer to perform switching from schematic one-line diagrams.

ReShape, the PRISM real-time schematic generator, will dynamically generate a switching one-line diagram of the current real-time feeder topology by clicking on the feeder in the geographic view. The schematic view does not display non-switching devices such as load transformers. However fuses, manual switches, reclosers, breakers, etc. are shown because each of these can alter the network topology.

The dynamically generated schematic view shows the current feeder connectivity from the source to the end of the feeder in a single window. The schematic view is simplified for easy comprehension by removing nonessential elements such as geographic information and distribution load transformers. The switching devices shown are equally spaced for optimum clarity.

Real-time Redline

Real-time Redline is an application that enables the dispatcher/operator to maintain changes to the network connectivity directly through the dispatcher/operators user interface.

Not all changes to the network connectivity are a result of planned changes, such as those resulting from storm damage. Neither are all changes permanent, such as temporary jumpers which are used to bypass civil construction or to allow outage-free maintenance. Real-time Redline permits the system operator to accommodate such scenarios. The Redline tool is intended to be easily used by the operator who can input ‘Cuts’ or ‘Jumpers’ quickly without performing changes in the GIS and undergoing a conversion process in order to reflect the actual network condition.

These network changes are intended to remain in place until the temporary condition passes or until the GIS is updated to reflects new permanent network construction. The PRISM Real-time OMS supports the ability to modify the network connectivity directly through the operator interface. The operator can select a line to insert ‘Jumpers’ between line segments and or create ‘Cuts’. The network topology model, upon which all network applications rely, will adjust accordingly to the Redline changes. Where a ‘Cut’ is inserted the OMS will automatically create an Outage Ticket to mark the location of the generated outage. When the ‘Cut’ is removed, the Ticket is automatically removed and the Call Back customers are informed.

Planned redline changes can be added prior to their activation, which performs the actual network connectivity alteration. In this way Redlines can be added prior to the crew actually implementing the change, and then activating it when the crew is ready to complete the change. Individual Redlines can be activated at which time connectivity and topology is updated. Subsequent updates to the network model originating from the GIS do not affect the existing Redlines.

All Cuts and Jumpers are marked by an icon on the map for easy identification.

Managing today’s distribution network demands powerful and flexible solutions.

Learn how ACS PRISM Advanced Distribution Management System meets those demands.

PRISM Portal – Enterprise Reporting

The ACS PRISM Portal solution is an integrated set of applications designed to deliver a broad range of information, graphics, and data not only satisfying the needs of all functional departments within the utility enterprise, but also answering the expectations of demanding users in an ad-hoc manner.

Built entirely in Java it provides complete report management, distribution, and administrative functionality while providing users with a simple and intuitive interface for interacting with reports.

Solutions Architecture

The solutions architecture is based on the typical 3-Tier Data, Application and Presentation layer model. The out of box solution provides the utility with the following:

  • PRISM Historian – this is the archiving application that is standard on the PRISM system and records changes to the RDBMS continuously
  • Utility Data Model
  • Reporting Server Modules
  • Cost-Effective Integration
  • Rich capabilities such as scheduling, security and publishing
  • Zero Client-Side deployment

XpertSim – System Simulator

XpertSim™ from ACS is a breakthrough in dynamic distribution system simulation that can be used for system optimization/planning as well as dispatcher training with real-life system scenarios.

With its innovative applications, utilities can achieve cost savings and operating performance increases previously considered unattainable.

XpertSim is easily scaled, so it creates exciting opportunities for budget-strapped utilities to improve customer satisfaction by minimizing outages and dynamically tuning the distribution system. XpertSim is a stand-alone program that can be positioned anywhere in your operational network with displays that can be integrated into your existing distribution management system (DMS).

DERMS – Distributed Energy Resources Management System suite

Interest in renewable integration within distribution networks is on the rise, both within the utility industry and with the public at large.

If the legacy SCADA is not PRISM ADMS, the best value for return of investment, with the fastest time to implement, is a distributed Centrix platform that integrates seamlessly with existing SCADA system, feeder devices, communications systems and remote terminal units. The solution is to deploy a flexible architecture to manage the various components seamlessly, without expensive changes to legacy systems. The ACS Distributed Energy Resources Management System (DERMS) offers this flexibility, enabling communication between the various devices necessary to accomplish the coordinated optimization of the feeder controlling devices.

Managing today’s distribution network demands powerful and flexible solutions.

Learn how ACS PRISM Advanced Distribution Management System meets those demands.