Regulation Deployment Priority Groups
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Presentation Transcript
Objectives • Provide analysis of the distribution of the regulation deployment during February 25th IDT when multiple priority groups were activated.
Background • Priority groups are currently designated once an hour for all regulation cleared resources. • The assignment is done by ID RUC for all regulation cleared resources, In addition, RTBM assigns a priority for any additionally cleared resources post ID RUC. • RTBM allocates any resource that didn’t clear in ID RUC for the product to the last priority group defined (last group to be used) • Designed to control the number of Resources that get deployed at a time to prevent the deployment of full fleet cleared for regulation. When full fleet clearing, we have previously shown that regulation is stranded in resource dead bands.
RTGEN • RTGEN determines the set of Resources to deploy when regulation is required by distributing regulation across the first group then moves on to the next group as needed. • The distribution to each Resource within a priority group is done pro-rata based on Resources’ capacity limited by ramp rate and Regulation cleared MW. • Prior to the Feb 25th IDT SPP has only used a single priority group in testing.
If we assumed a 3MW dead band – need 100 MW of regulation deployment before we get 82% response (0-1MW and 1-2MW categories are stranded) Over 35% (5.55+5.95+23.92) of the occurrences SPP has deployed 75MW or less of regulation when over 80% (37.82+43.53) of regulation is stranded
The MW distribution and the resource distribution are highly correlated
Change Summary • Six priority groups were activated in ID RUC and RTBM for February 25th IDT. • On average each group was allocated 3 – 4 resources. • The methodology for priority groups allocation methodology was set to random. • The last group ( group # 6) was allocated the most number of resources. This is because ID RUC cleared differently for certain resources than RTBM. When ID RUC doesn’t clear regulation (up or down) on a resource, it doesn’t assign a priority group. RTBM instead assigned a priority group of the highest defined group. • RTGEN AGC gain factors were adjusted by -25%, this reduces regulation deployment.
Interpretation • Regulation deployment per resource is more uniform with multiple priority groups activated. • Small regulation deployment per resource is minimized, hence, achievable regulation response even at small system total regulation deployment. • Prior to using priority groups 80% of the deployed regulation was stranded when up to 75MW of regulation was called on. Compared this to less than 20% during the 25th IDT with priority groups (assumption is 3MW dead band on regulation resources)
Recommendation • Regulation deployment was significantly more uniform in terms of MW deployment on each resource across different system regulation deployment ranges • Regulation deployment across each resource is more significant in magnitude minimizing deployment within dead band concern. • Randomly allocating resources into different groups helps mitigate resources from being in same group for longer than an hour. • Exception to resources that RTBM clears for a product but not ID RUC. • SPP recommends that 6 priority groups be activated at Go-Live or soon after to mitigate potential slow regulation response. (change required protocol change and MOPC approval)
Priority Group Methodology • Multiple methodology options are developed and are configurable. • Random Priority Group assignment • If Priority Group defined are greater than one, resources are distributed evenly across the different groups. • Resources will be selected based on the zones they belong to. • Randomly select and distribute the resources cleared from each zone into different priorities, if possible • Once each priority contains a resource from these defined reserves zones, RTBM will ensure that the priority with least MW regulation assigned would have higher probability of being assigned more units. • The effective ramp rate of the resource. • The higher the effective ramp rate in the up direction would force the resource in the higher priority for Reg-up bucket. The higher the effective ramp rate in the down direction would force the resource in the higher priority for Reg-down bucket.
