Using Optimization in Real-Time Mode
In real-time mode, when enabled, Optimization runs in the background and generates recommendations for the current network topology using predicted loads for the short-term future (for example, 4 to 6 hours).
Setting the Optimization Mode
To enable a feeder for Optimization, the feeder type must be Primary Xfmr or Primary. The feeder type can be set using Configuration Assistant Feeder Management Tab (see Using the Feeder Management Tab for details).
The Feeder’s Optimization Objective can be set to Conservation Voltage Reduction, Loss Minimization, Power Factor Correction, Relieve Violations, or Maximize Voltage using Configuration Assistant Feeder Management Tab (see Using the Feeder Management Tab for details). Power Factor Correction will solve for a loss minimization objective, but only consider using capacitors, not LTCs or Line Regulators.
Optimization can be set to run Fast Cycle, which occurs at the end of each Feeder Load Management (FLM) cycle, or Slow Cycle, which occurs at the end of each FLM forecast.
Optimization supports four different modes of operation:
• Disabled: Optimization does not run.
Note: When a single feeder(s) is set for Disabled mode, Optimization will restore the feeder's regulation devices to nominal during the next optimization cycle. During this scenario, the plan may consist of a blend of optimization steps and return to nominal. For example, if one feeder on a bus containing five feeders was set to Disabled, the steps would consist of return to nominal for that feeder and optimization for the other four feeders (see Using the Feeder Management Tab for details on disabling a single feeder).
• Manual: Optimization runs periodically for every hour and configured FLM cycle time. Feeders that require optimization in specific periodic execution can be set with desired objectives modes of the feeders in the Configuration Assistant Feeder Management tab (see Using the Feeder Management Tab for details). It checks the real-time load scenario, and recommends DER dispatch and shunt device, transformer, and regulator status changes, if there is a significant benefit. The recommendation plan will not be executed automatically.
• An operator may view recommendations by opening the Optimization solution.
• An operator has to manually create a switching sheet from the plan and execute it.
• Automatic: Optimization runs periodically for every hour and configured FLM cycle time. Feeders that require optimization in specific periodic execution can be set with desired objectives and modes of the feeders in the Configuration Assistant Feeder Management tab (see Using the Feeder Management Tab for details). However, the status of the other feeders on the same substation Load Tap Changer can influence the mode of this feeder. It checks the real-time load scenario and recommends shunt device and transformer/regulator status changes, if there is a significant benefit. The recommendation plan will be executed silently. An event (O-NEW) will be created and displayed in the Work Agenda for the plan execution.
• Return to Nominal: During the next optimization cycle, Optimization will begin returning all optimization enabled devices to their nominal regulation settings. The plans will be executed automatically in real-time. This would generally be used for situations where the entire service territory needs to be returned to nominal (for example, due to an impending storm or other emergency situation). The nominal settings are stored in the NMS database and will be used in the steps generated by the tool. The application will attempt to restore any set-points, position, or step would be different from the nominal value. For example, a substation load tap changer (LTC) may have two steps to return it to nominal; the first step would be to adjust the voltage target set-point and the second would be to adjust the tap step.
Note: The Return to Nominal mode is not set on a single feeder or group of feeders; it is a global mode that is accessible from the Web Workspace Tools menu and applies to all Optimization enable feeders.
To set the optimization mode, from the Web Workspace Tools menu, select DMS Settings, and then Optimization Mode, and, finally, select the desired mode (Disable, Manual, Automatic, or Return to Nominal). Also select the desired Optimization modes of the feeders in the Configuration Assistant's Feeder Management tab (see Using the Feeder Management Tab for details). Note that Feeder Load Management must be running for the Optimization Mode options to be enabled; see Chapter 18, Feeder Load Management for more information. Also make sure that the FLM mode of these feeders is set to Forecasting in the Configuration Assistant Feeder Management tab (see Using the Feeder Management Tab for details).
Understanding Optimization Events in the Work Agenda
The Work Agenda DMS Status column provides information about Optimization events and results of the calculations. When row or cell coloring is enabled in the Web Workspace (see Understanding the Table Settings Menu for more information), the DMS Status information is color coded. Possible Optimization status results:
DMS Status Column
Description
Optimization Solution Generated
Optimization has found a solution.
Optimization Solution Generated with Violations
Optimization has generated a solution, but it contains violations; manual intervention is required if in automatic mode.
Optimization Automatically Executing
In automatic mode, Optimization has generated a plan and is automatically executing the plan.
Optimization Automatically Executed
In automatic mode, Optimization has generated a plan and has automatically executed it.
Optimization Automatic Execution Failed
In automatic mode, Optimization has generated a plan and attempted to automatically execute it, but it failed.
Optimization Manually Aborted
Optimization processing or execution has been aborted by a user.
Demoting Optimization Plan to Manual
When Optimization is in automatic mode and the produced plan contains violations worse than those present in the current network, the plan will be demoted to manual. This will allow an operator the ability to review the Optimization recommendations and determine if the violations that have made the network worse are still worth implementing. If the decision is made that the plan is viable they can then create a switching sheet and execute it.
Optimization uses configured relaxations for voltage and thermal limits to assess. Once the violations are identified, it then applies weightages specified for each type of device violation based on the SRS rules. Administrative Users can customize these weights to their preferred values using Configuration Assistant, thereby controlling the optimization process and the decision to demote the plan to manual.
Configuration (Administration Users)
The following SRS rules need to be configured using the Configuration Assistant to control the optimization demoting a plan to manual.
Rule: Allowable Voltage Percentage Beyond Limit
• Rule_value_2: Percentage of voltage relaxation beyond its limit to not to treat a voltage alarm as a violation.
Rule: Allowable Thermal Percentage Beyond Limit
• Rule_value_2: Percentage of thermal (loading) relaxation beyond it’s limit to not to treat an overload alarm as a violation
Rule: Use Weighted Factors Analysis for Violations
• Rule_value_1: Set to "yes" to use weighted factors to calculate the score of violations base on violation type, overload factor and device type. A plan is a better plan if the score of violations in the plan is same or lower than the score of violations in the current network.
Set "no" to determine a plan is better or not base on number of violations in comparison with number of violations in the current network.
Rule: Optimization Conductor Violation Weight
• Rule_value_2: Weight factor for conductor violation.
Rule: Optimization Distribution Transformer Violation Weight
• Rule_value_2: Weight factor for distribution transformer violation.
Rule: Optimization Feeder Breaker Violation Weight
• Rule_value_2: Weight factor for feeder breaker violation.
Rule: Optimization Load Imbalance Violation Weight
• Rule_value_2: Weight factor for load imbalance violation.
Rule: Optimization Power Transformer Violation Weight
• Rule_value_2: Weight factor for power transformer violation.
Rule: Optimization Switches Violation Weight
• Rule_value_2: Weight factor for switch violation.
Rule: Optimization Distributed Generation Violation Weight
• Rule_value_2: Weight factor for distributed generation violation.
Rule: Optimization Under Volt Violation Weight
• Rule_value_2: Weight factor for voltage under limit violation.
Rule: Optimization Over Volt Violation Weight
• Rule_value_2: Weight factor for voltage overlimit violation.
Rule: Optimization Warning Weight
• Rule_value_2: Weight factor for warning in optimization.
Understanding the Number of Retries for a Timed Out Step
If no response (related to a plan's switching action) is received from SCADA within the configured timeout period, then the switch step status will be set to a value of Failed. When the Optimization plan is executed in automatic mode, or when the plan is manually executed using the Execute the entire plan toolbar option, the plan execution can retry a timed out step for configurable number of times before it sets the status of the switch step to Failed.
Configuring the Number of Retries for a Timed Out Step (Administration Users)
To allow the plan to retry the actions when they time out, configure the rule DMS Switching Step Fail Retries and Wait Time in the Configuration Assistant Event Management Rules tab.
Note: The rule may be searched for or you may expand DMS Application Rules and then SCADA Measurement Rules.
Add an instance of this rule for Optimization plans. Configure the following:
• rule_value_2: Enter the Optimization sheet class (found in the SWMAN_SHEET_CLS table).
• rule_value_integer_1: Enter the maximum number of retries to perform before setting the step as Failed.
• rule_value_integer_2: Enter the time to wait before retrying the action.
See Using the Event Management Rules Tab for more information on configuring rules.
Aborting an Optimization Plan
To abort an Optimization plan from the Work Agenda, right-click the Optimization event and select Abort DMS Processing from the context menu.
Alternatively, in the Optimization switching plan, right-click the Optimization event in the Events table and select Abort DMS Processing from the context menu.
Understanding Optimization Setpoint Limits
The optimization algorithm has parameters related to voltage setpoints that can be tuned via project configuration. Voltage setpoints are recommended by the optimization application to adjust the target output voltage at substation power transformers and voltage regulators. Configuration exists to also allow projects to determine whether plans should be demoted to manual execution if one of these limits has been breached and the area is configured for automatic execution.
Setpoint Magnitude Limits
The first type of adjustable parameters are related to the magnitude of the setpoint recommended. In some cases, projects may want to ensure the optimizer never recommends a value that exceeds an upper threshold or falls below a lower threshold. In some situations where data has become inaccurate, or modeling issues occur the optimizer may come up a plan that results in abnormal setpoints. For example, if the optimizer came up with a voltage setpoint of 1.08 PU but the upper threshold was set to 1.05 PU that optimization plan step to adjust the value would be altered to contain the upper threshold of 1.05 PU instead of the original 1.08 PU value. The same would hold true for situations where the recommended setpoint falls below the lower threshold. When one of these thresholds has been exceeded a message will be placed in the "Optimization Messages" pane of the Optimization report stating that the "setpoint limit has been exceeded" and will show the value that was originally recommended by the optimizer and the phase which the issue occurred on.
Setpoint Differential Limits
The second type of adjustable parameters are related to the voltage differential between the setpoints recommended for a single device. For un-ganged regulators where a setpoint is created on each phase it may be desirable to keep each setpoint within a certain percentage of each other to ensure balanced voltage at downstream three phase customers. For example, if the rule was set to 1% an acceptable set of per phase setpoints would be 1.01/1.01/1.02 (A/B/C). Whereas 1.01/1.02/1.03 (A/B/C) would not be acceptable as there is a 2% difference between the Phase A and C setpoint. When one of these thresholds has been exceeded a message will be placed in the "Optimization Messages" pane of the Optimization report stating that the “setpoint differential limit has been exceeded” and will show the voltage difference between the two phases and the specific phases involved in the issue.
Configuration (Administration Users)
To adjust the setpoint limit parameters, the following SRS rules should be changed using Configuration Assistant.
Rule: Optimization High Setpoint Limit
• Rule_value_2: The maximum setpoint that can be issued at a device for normal optimization plans.
Rule: Optimization Low Setpoint Limit
• Rule_value_2: The minimum setpoint that can be issued at a device for normal optimization plans.
Rule: Optimization High Setpoint Limit FLISR
• Rule_value_2: The maximum setpoint that can be issued at a device for FLISR optimization plans.
Rule: Optimization Low Setpoint Limit FLISR
• Rule_value_2: The minimum setpoint that can be issued at a device for FLISR optimization plans.
Rule: Unganged Regulator Maximum Voltage Difference
• Rule_value_2: The maximum voltage difference between any of the phases present on the un-ganged voltage regulator.
Rule: Demote VVO Plans with Setpoint Limit
• Rule_value_1: If set to “Yes” then optimization plans with a setpoint limit violation will be demoted to manual execution if the area is configured for automatic execution.
Tracking Number of Operations on Capacitors and Penalizing Them
To limit the over utilization of capacitors and mechanical wear on capacitors, the number of close operations on SCADA capacitors are tracked on a device by device basis. If the count of the operations on a capacitor (in a configurable time period) exceeds a threshold configured for the class of the device, then Volt/VAr optimization will penalize the capacitor in its real time plans. First the optimization will try to come up with a feasible plan by excluding the capacitor. If there are still violations, then it will attempt to use the excluded capacitor to relieve more violations.
Configuration (Administration Users)
To enable this, the following SRS rules need to be configured using Configuration Assistant.
Rule: Capacitor Operations Count Penalty Threshold
• Rule_value_1: Class name of the capacitors
• Rule_value_2: Threshold count of close operations to penalize a capacitor
Rule: Capacitor Operations History Period
• Rule_value_2: Number of days to consider back in time to count the close operations. By default, it is one day (last calendar day).
Rule: Use Rolling Period Capacitor Operations Count to Penalize
• Rule_value_1: yes or no. By default, it is no (use the count of operations in the last calendar day). If it is set to yes, then the operations in the last 24 hours are used to determine the count and penalize the capacitors.
Rule: Capacitor Operations Penalty Weight
• rule_value_integer_1: Enable: 0 - No, 1 - Yes. Default: 0.
• rule_value_2: Weight.
Note: Currently weight is not in use. Optimization penalizes a capacitors whose operations exceed a threshold by excluding it, if rule_value_integer_1 is set to 1. If there are still violations in the plan, it checks if the capacitor can help relieve them. If it helps, then it will come up with a plan that includes the capacitor.