Load Distribution Factors (LDFs)

Transcription

1 Load Distribution Factors (LDFs) CRR Educational Class #8 CAISO Market Operations

2 Why are LDFs important to the CRR Allocation? The APnodes for the standard Sinks will in general be based on Load Distribution Factors (LDFs) The APnodes determine how certain Sources and Sinks are allocated to the underlying FNM This in-turn plays a role in the resulting flow on branches and interfaces in the CRR Allocation process LDFs also play a role in determining the prices used in the CRR revenue calculations 2

3 Course Objectives Upon completion of this course, you will be able to: Understand Load Distribution Factors Know that Load Distribution Factors vary relative to each other throughout the year Have an understanding on how the variation in LDFs may have an impact on revenue adequacy 3

4 Agenda What are LDFs Determination of Load Example calculation of LDFs Variation of load over time The use of LDFs in the CRR Allocation and Integrated Forward Market LDF impact on Revenue Adequacy 4

5 What are LDFs LDFs are allocation factors Based on Load Greater than or equal to 0.0 Less than or equal to 1.0 Sum to 1.0 or 100% (normalized) The % of load on a bus to total load within a given set of load buses A mapping used to allocate aggregate load to underlying FNM nodes/buses Integrated Forward Market CRR Allocation 5

6 Determination of Load How is load determined in order for LDFs to be calculated? Note that the load at a FNM bus represents the flow through the connection of the transmission system to the distribution system That is, the flow from the transmission system to the distribution within the Transmission/Distribution (T/D) substations If there were Supervisory Control and Data Acquisition (SCADA) metering/telemetry at all T/D substations, LDFs would be easy to calculate The load would be measured and measured fairly accurately The LDFs can be easily calculated from this measured load However, SCADA metering is present at some substations but not present at all substations Because of the lack of load SCADA metering at the bus level other means are necessary to determine and develop LDFs 6

7 Determination of Load Two Sources of Load for LDF determination Load from within a base case Base cases are network models that best represent a certain time of year or other certain conditions in terms of load, import/export and generation pattern, and network topology Captures variations in seasonal and time-of-use periods This load is based on metering from non real-time metering technology and some real-time metering Non real-time metering may include Peak day circle charts that are read manually Base cases provided by PTOs to WECC and then to ISO Other sources This may include an LDF library that is populated from state estimation solutions (an Energy Management System application) 7

8 Calculation of LDFs - Example Assume the following transmission network The loads are loads from a certain base case They could also be a result of a state estimation solution Assume two Standard Load Aggregations Load Aggregation 1 Load Aggregation 2 8

9 Calculation of LDFs - Example Base case example Sample FNM Load Aggregation Point 1 Gen node Load node Connection node Node 10 Transmission line Load Aggregation Point Load from base case (MW) Boundary

10 Calculation of LDFs - Example The LDFs for each Load Aggregation Point are calculated as Normalize the loads Sum the load within each Load Aggregation Point Total Load in Load Aggregation Point 1 is 150 MW Total Load in Load Aggregation Point 2 is 200 MW Divide each load value by this sum For Load Aggregation Point 1 divide each load in this aggregation by 150 MW For Load Aggregation Point 2 divide each load in this aggregation by 200 MW 10

11 Calculation of LDFs - Example Resultant LDFs Load Aggregation Point 1 6.7% 13.3% 20% 26.7% 25% Load Aggregation Point 2 20% 6.7% 26.7% Boundary 10% 20% 5% 15% 5% 11

12 Calculation of LDFs - Example Note that there may be exceptions and not all load within a certain area will be part of the aggregation, for example Custom load aggregation (not applicable at this time) Dispatchable load Existing transmission contract load Other loads To calculate the LDFs for the remaining load These exceptional loads will first be removed The remaining load will be normalized 12

13 Variation of Load Over Time It is important to understand that there is variation in the distribution of the load within the control area over time Over a period of one year, the temperature in the various regions of the control area changes relative to each other Load level is dependent on temperature More change in temperature in some areas More change in load in these areas Less change in temperature in some areas Less change in load in these areas 13

14 How Load Varies in Aggregate (System Wide) Load increases with temperature 24,000 Peak Load vs Temperature 22,000 Load (MW) 20,000 18,000 16,000 14,000 12, Temperature 14

15 How Load Varies in Sub-areas Temperature depended statistics Sub-area loads vary with temperature at different rates For example (purely sample data) Assume summer peak load conditions Peak load increases for every degree in peak temperature Northern California Coastal 0.3 MW/Degree Southern California Coastal 0.7 MW/Degree Sacramento Valley 3.0 MW/Degree These statistics shows the variation throughout different parts of the control area 15

16 How Different Load Types Vary Different load types have different load profiles Industrial and agricultural loads do not correlate well to temperature Commercial loads correlate with temperature but also vary significantly from weekday to weekend Residential loads correlate best with temperature Load at the T/D substation Some T/D substations can be almost all residential load, all commercial load, or a mixture of commercial and industrial, etc. Therefore based on the previous temperature depended statistics some bus loads (that are modeling the T/D flow) may be more temperature dependant than others 16

17 LDF Variation Example Simple Example showing load variation within regions of a load aggregation Assume that the resulting LDFs will be used in the Forward Market Assume 3 load buses within a load aggregation Bus1 in the southern coastal region of the load aggregation Bus2 in the inland region of the load aggregation Bus3 in the northern coastal region of the load aggregation 17

18 LDF Variation Example Assume the loads are measured for a given day at peak temperature for each area: T 1, T 2, T 3 Southern Coastal Inland Northern Coastal Bus1 Bus2 Bus3 MW load value LDF 25% (100/400) 100 MW 200 MW 100 MW 50% (200/400) 25% (100/400) 18

19 LDF Variation Example Assume the loads are now measured on the next day at peak temperature Ti + ΔTi Assume that the measured loads are consistent with the previously given factors or 0.7, 3.0 and 0.3 MW/Degree ΔT 1 = 10 degrees ΔT 2 = 20 degrees ΔT 3 = 5 degrees Southern Coastal Inland Northern Coastal Bus1 Bus2 Bus3 MW load value LDF * MW 22.84% (107/468.5) * MW 55.50% (260/468.5) = * MW 21.66% (101.5/468.5) 19

20 LDFs Used in the CRR Allocation and Auction The ISO plans to use a seasonal allocation time period for the annual CRR allocation process The ISO must determine one set of LDFs to use per season per TOU Based on the previous discussion within this presentation, the variation of LDFs within the seasons and TOU periods may be minimal as compared to the actual day-to-day and hourto-hour LDF variation 20

21 LDFs Used in the Integrated Forward Market The Integrated Forward Market will generally use more up-to-date LDFs for the load scheduling as compared to the CRR allocation process The Integrated Forward Market is processed every day and the opportunity to updates the LDFs is available The use of the state estimation process may information for the day-to-day update of LDFs 21

22 LDF impact on Revenue Adequacy It is important to understand that there is variation in the LDFs over time and in particular a variation of the LDFs used between the CRR Allocation and the Integrated Forward Market This was already noted in the Pricing and Aggregated Pricing Nodes presentation Assume that the CRR revenue price is calculated based on the allocation factors used in the Integrated Forward Market APnodes These may be different than those used in the CRR Allocation process Revenue Adequacy is no longer guaranteed if the allocation factors are the same 22

23 LDF impact on Revenue Adequacy Bottom line on LDFs Because of seasonal temperature variations, and different load types, load distribution factors change significantly relative to each other from season to season and from off-peak to on-peak In other words, the relative magnitude of the LDFs changes from from season to season and from off-peak to on-peak Because the CRR terms are on a seasonal/monthly basis, the LDFs variation within the season/month may be minimal as compared to actual LDF patterns This in turn will create a minimal variation with the LDFs used in the Integrated Forward Markets and may minimize any revenue inadequacy assuming the CRR revenue is based on Integrated Forward Markets LDFs 23

24 Any Questions? 24