Dynamic Cable Rating Model Guidelines

Transcription

1 lines Introduction This document describes how to set up, configure and run the Dynamic Cable Rating model in Ipsa. The Dynamic Cable Rating model (DCR) has been developed for the WPD FALCON project by Aston University. It models the thermal time constants of a cable and the surrounding soil to determine the cyclic cable rating. The DCR model is provided in the form of an Ipsa Plugin model. It can be added to any cable in the network by following the instructions in the section below. A test network is provided as well as a Python script to assist in the set up of the model. The model calculates the continuous and cyclic ratings of the cable based on the time varying current that flows through it. The Profile analysis in Ipsa is used to represent the time varying network demands. The analysis therefore calculates the current through the cable based on the profile data in the network. The cable current ratings are calculated as single values which are dependent on the shape and magnitude of the profile. The model does not calculate tie varying ratings. The model also calculates the number of times the current ratings are exceeded during a Profile analysis. This guide contains the following sections; 1. Data Requirements 2. Add DCR Model to Ipsa 3. Add Extended Data to Network Model 4. Add DCR Model to Cable 5. DCR Simulations September 2013 Page 1

2 Plugin Model Data Dynamic Cable Rating Model Guide 1. Data Requirements The data required for the DCR model includes the dimensional cable data and thermal parameters of the cable and surrounding soil. All the data is entered into the Plugin Properties dialog. The following tables provide a summary of the input data requirements together with the default values. All data should be entered into Ipsa without units. The DCR model calculates the continuous and cyclic ratings of the cable based on the time varying current that flows through it. The rating results are presented in the extended data associated with the cable. Note that all busbars in the model should have a nominal voltage assigned to them, thereby allowing Ipsa to calculate the cable currents. Table 1 - DCR Data Parameters for the Plugin Parameter Maximum Conductor Temperature (deg C) Default Values 90.0 C Description Maximum allowable conductor temperature in degrees C Burial Depth (mm) 600mm Cable burial depth in mm. Must be greater than 0.0 Cable Diameter (mm) 39.1mm Cable diameter in mm. Must be greater than 0.0 Trefoil = 1, Flat = 2 1 Enter 1 for a trefoil cable, 2 for flat installation with spacing Flat Spacing Factor 0 Spacing between ducts in multiples of the duct diameter. Enter wholes only. For example enter a value of 2 to represent 40mm diameter cables with a spacing of 80mm. Used for flat installation only Screen Diameter (mm) 32.78mm External diameter of the cable screen in mm. Must be greater than 0.0 Insulation Diameter (mm) 29.6mm External diameter of the cable insulation in mm. Must be greater than 0.0 Conductor Diameter (mm) 20.5mm External diameter of the cable conductor in mm. Must be greater than 0.0 Screen Area (mm^2) 35.0mm 2 Cross sectional area of the cable screen in mm 2. Must be greater than 0.0 DC Resistance at 20degC (ohms) Ω DC resistance of the conductor at 20 C in ohms Insulation Thermal Resistivity (m degc/w) Outer Cover Thermal Resistivity (m degc/w) 3.5 m C/W Thermal resistance of the cable insulation material in metre-degrees centigrade per watt 3.5 m C/W Thermal resistance of the cable outer layers in metredegrees centigrade per watt October 2013 Page 2

3 Extended Data Outputs Plugin Model Data Dynamic Cable Rating Model Guide Parameter Conductor Temperature Coefficient (degc -1 ) Screen Temperature Coefficient (degc -1 ) Conductor Resistivity at 20degC (m degc/w) Default Values C C x 10-8 C/W Description Temperature coefficient of the cable conductor material resistance in degc -1 Temperature coefficient of the cable screen material resistance in degc -1 Conductor thermal resistivity measured at 20 C in metre-degrees centigrade per watt Ambient Soil Temperature (degc) 10 C Ambient soil temperature for the cable Soil Thermal Diffusivity (m 2 /sec) 5 x 10-7 m 2 /sec The soil diffusivity, or conductivity, in metres 2 per second Soil Thermal Resistivity (m degc/w) 0.9 m C/W Thermal resistance of the soil and materials surrounding the cable in metre-degrees centigrade per watt Table 2 - DCR Output Data Parameter Cyclic_Rating_Amps Sustained_Rating_Amps Cyclic_Overloads Sustained_Overloads Description The cyclic cable rating calculated by the DCR model is presented in this field. Value is in amps. The sustained or continuous cable rating calculated by the DCR model is presented in this field. Value is in amps. The number of cyclic overloads identified during the last profile analysis. This value is reset for each profile analysis. The number of sustained overloads identified during the last profile analysis. This value is reset for each profile analysis. October 2013 Page 3

4 2. Add DCR Model to Ipsa 2.1. The DCR model is provided in the form of a DLL file and is normally supplied as part of the Ipsa install Confirm that there is a file called IFalconDynCableRating.dll in the Ipsa plugins directory C:\Program Files\IpsaPower\Ipsa 2.3\plugins, as shown below; October 2013 Page 4

5 2.3. The DCR model will be checked when Ipsa is launched and the user can check it has been correctly loaded by starting Ipsa and viewing the Progress window. The following message will be displayed if the model is present; 2.4. If the above message is not displayed then please contact for further assistance. October 2013 Page 5

6 3. Add Extended Data to Network Model Some of the cable data is set using Ipsa Extended Data fields. For convenience a Python script has been provided which configures the required Extended Data fields automatically. Perform the following steps to add the required data fields to each Ipsa network; 3.1. Open the Ipsa network containing the transformers to which the DCR model is to be applied 3.2. Go to the Analysis menu and select the Run Script item 3.3. Navigate to the ConfigureDCR.py script. Normally this will be in the Ipsa script directory should below. If the script has been ed or downloaded from the website then navigate to the folder where it was saved into. C:\Program Files\IpsaPower\Ipsa 2.3\scripts 3.4. Select the script and click Open. The script will prompt you as required and issue warnings if not successful. Please contact support@ipsa-power.com if errors are encountered. October 2013 Page 6

7 4. Add DCR Model to Cables 4.1. Open the network model in Ipsa and locate the line which is to have the DTR model added to it Display the Line properties dialog shown below by either; Double clicking the branch on the diagram Double click the item in the stack bar 4.3. Select the Main tab 4.4. Select the FALCON Cable DAR from the selection box. The dialog will now display the selected plug-in name and an Edit button as shown below; October 2013 Page 7

8 4.5. Click the Edit button and the DCR Properties dialog will be displayed as shown below. This dialog contains the thermal properties for the cable; 4.6. The parameters can be edited as required for each cable. The Restore Defaults button can be used to return to the default parameters as shown above Click OK to save the data and return to the Line dialog 4.8. The rating results are presented in the extended data fields for the line October 2013 Page 8

9 4.9. Click the Extended Data tab in the Line dialog to view the rating result fields, as shown below; Click OK to save the data for the Line The DCR model is now ready for use October 2013 Page 9

10 5. DCR Simulations The DCR model is intended for use with Ipsa load profiles to allow a time series representation of the network load changes. The model will run automatically during any Profile studies, it will not run during normal load flow studies. No further set up is required in order to run the model. For this version of the model all output data is saved in the extended data fields associated with the line. A test network has been provided which can be used to ensure that the model operates correctly. This network contains a line with a DCR model and a load profile. Follow the steps below to run the model and reproduce the test case results; 5.1. Open Ipsa and open the Profile Test network supplied with the DCR model 5.2. This contains a line with a DCR model, the model properties are shown below; October 2013 Page 10

11 5.3. The model also contains a single 11kV load with a profile as shown above. This profile contains 48 values representing one day of half hourly demand data Click on the Analysis menu and select the Run Profile option. This runs all the load flow calculations for the profile associated with the load. The results are presented in the Progress window as shown below, indicating the number of profile periods that the ratings were exceeded; [Oct :26:22] Starting profile analysis [Oct :26:22] Plugin item FALCON Cable DAR controlling Busbar1.Busbar2.Line connected to plugin (FALCON Cable DAR) instance [1] [Oct :26:22] Plugin: loaded model (FALCON Cable DAR): FALCON Cable DAR controlling Busbar1.Busbar2.Line [Oct :26:22] Plugin FALCON Cable DAR [1]: Cable extended data DCR parameters ok [Oct :26:22] Plugin FALCON Cable DAR [1]: Cable sustained rating of amps exceeded for hours [Oct :26:22] Plugin FALCON Cable DAR [1]: Cable cyclic rating of amps exceeded for hours [Oct :26:22] 24 profile categories run The calculated cable rating results are shown in the extended data for the branch. Double click on the branch and select the Extended Data tab, as shown below; October 2013 Page 11

12 5.6. The diagram results also show the maximum and minimum current flows; October 2013 Page 12