Utilizing customer/load data and available power flow measurements, the Phase Prediction application assigns phases to laterals with unknown phase information. This allows distribution engineering analyses (e.g. power flow studies) to be performed on circuits that could not be adequately analyzed without phasing information.
See Phase Prediction Setup for details on user input options for this application.
For general details on running an application, selecting and displaying output variables, see Running DEW Applications.
The Available Output Variables for the application are described in the last section of this topic.
Phase Prediction basically utilizes two types of information:
System Measurements
Customer (Load) Information
Phase Prediction requires a set of power flow measurements (on each phase) to exist at the start of circuit. If kW or kVAR are not measured directly, then they can be determined from other measurements available (i.e. voltage, current, power factor).
In addition to the start-of-circuit measurements, other sets of measurements at interior points in the circuit (e.g. capacitor banks, etc) may be utilized to improve accuracy of Phase Prediction.
Phase Prediction starts by predicting laterals served (i.e. downstream) of the outermost measurement points and then moving inward to the start of circuit.
To predict lateral phases that are representative of annual load variations, circuit measurements from a number of different time points (i.e. summer peak, summer average, winter peak, winter average, etc) should be considered, when available.
The objective of this application is to match circuit power flow measurements of kW and/or kVAR with the estimated load values (for power flow) by assigning phasing to single and two phase laterals with unknown phases.
Estimated power flow values are calculated from the Load Estimation algorithm due to potential convergence issues in the Power Flow method that result from the assumed phasing of unknown laterals. With unknown but assumed phasing, the initial loading on circuit may be such that there is no steady state Power Flow solution.
Estimated power flow values are affected as phase assignments are varied.
Phases that result in
the minimum mismatch are recorded as predicted phases.
Phase Prediction also includes the Phase Balancing analysis in its solution,
making it useful for planning upgrades to optimize re-phasing of circuit
laterals and loads.
See Running DEW Applications for general details on running an application, selecting and displaying output variables.
Before initiating the Phase Prediction run user should verify:
Unknown lateral phases are set to Allow Device Movement (i.e. Lock Cmp flag Unchecked)
Known
lateral phases have the Lock
Cmp flag Checked,
i.e. with Allow Device
Movement set to NO.
Availability of
measurement data to determine which Measurements
and Types
will be used during run.
Algorithm Synopsis:
The objective of this application is to match circuit power flow measurements of kW and/or kVAR with the estimated load values (for power flow) by assigning phasing to single and two phase laterals with unknown phases.
Estimated power flow values are calculated from the Load Estimation algorithm due to potential convergence issues in the Power Flow method that result from the assumed phasing of unknown laterals. With unknown but assumed phasing, the initial loading on circuit may be such that there is no steady state Power Flow solution.
Estimated power flow values are affected as phase assignments are varied.
Phases that result in the minimum mismatch are recorded as predicted phases.
Phase Prediction uses the Tabu Search algorithm, which is an iterative procedure developed for solving combinatorial optimization problems.
Generally, Maximum Iterations are set to values from 100-500. The default value is 200.
For most users, Tabu Tenures should remain set to Auto, as setting this value too small may cause cycling and setting value too large can deteriorate solution quality.
For more information
on Phase Prediction theory, refer to related publications from EDD Web site.
After the Phase Prediction run, the circuit is in the modified phase configuration and DEW displays dialog for user to choose:
[Yes] - to Restore the circuit to the Original state; or
[No] - to Leave in the Predicted Phase configuration.
DEW then exits the application and displays the Phase Prediction Report (when generated by setup).
For general details on running an application, selecting and displaying output variables, see Running DEW Applications.
For this application, the Phase Prediction Report is generally the best way to review output, as it indicates both the original and predicted phase configurations, while not requiring user to leave circuit in the predicted phase configuration to review.
If the user prefers to review output graphically on the drawing, Phase Prediction does produce one output variable that is available for display, as shown in the following table.
|
Variable |
|
Description |
|
PhPresnt |
- |
Phases Found/Predicted on the Components |
Notes:
PhPresnt variable is valid only when displayed on the Predicted Phase configuration and will not be meaningful if user Restores circuit to Original state.
Displaying phases found or predicted for laterals on the drawing can done either using the Color by Phase View or by using Display Analysis Results, where:
0.0 - represents predicted phase-A
1.0 - represents predicted phase-B
2.0 - represents predicted phase-C
Displayed output from Phase Prediction also indicates which laterals the analysis considered unknown with an indicated Ellipse shown on drawing and "attached" as a component message. Laterals not indicated with ellipse were considered to be known (i.e. No Allowed Device Movement) in the analysis.