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Regulation Deployment Priority Groups. Objectives. Provide analysis of the distribution of the regulation deployment during February 25 th IDT when multiple priority groups were activated. Background. Priority groups are currently designated once an hour for all regulation cleared resources.
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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.
