Estimation of Active and Reactive Flexibility Range in Primary Substations

Transcription

1 Estimation of Active and Reactive Flexibility Range in Primary Substations João Silva, Jean Sumaili, Ricardo Bessa, Luís Seca, Manuel Matos Centre for Power and Energy Systems - INESC TEC October, 2016 Research and Technological Development Technology Transfer and Valorisation Advanced Training Consulting Pre-incubation of Technology-based Companies

2 Framework Introduction New and evolving DSO activities Extender DSO roles Associated services Main goal The reinforced cooperation between TSOs and DSOs to improve the system security Contributor to System Security Manage TSO s requests at different timeframes (network planning, operational planning, real-time operations, & ex-post) Estimate Flexibility Range of the Primary Substations Distribution System Optimiser 2

3 General Concepts Objective Estimate the flexibility area in each primary substation (TSO-DSO interface) considering the available flexible resources and cost in each distribution network Methods Interior-point method based optimization Several optimization problems were solved in order to find the extreme points of the flexibility area 3

4 Methodology Concept Establishing a region of PQ values The optimization problems allow to find a region of admissible P and Q values that may be provided in the boundary nodes by the distribution system through the network and contracts flexibility Algorithm to find the feasible values Maximize/minimize the P+βQ for different values of β Q max QTSO/DSO Min/Max P+βQ Q min P min PTSO/DSO P max MW However, due to the dependence between active and reactive power, not all the P and Q values inside the region can occur at the same time 4

5 Optimization Problem Formulation Subject to : 5

6 Optimization Steps Minimize Maximize P DSO TSO + β Q DSO TSO where β = tan θ of θ = 0, 90, 90, 45 and 45 OR Minimize Maximize P DSO TSO where Q DSO TSO = fixed Q on DSO/TSO boundary Subject to: - Network constraints (e.g., active power balance, voltage magnitude, etc.) - Flexibility limits - Maximum flexibility cost 6

7 Tool Framework 7

8 Main Results Flexibility provided by the DSO flexible assets and DRES curtailment Maximum Flexibility Area Flexibility Area Constrained to a higher Flexibility Cost Flexibility Area Constrained to a lower Flexibility Cost The methodology proved its effectiveness in constraining the optimization problem to different maximum flexibility costs 8

9 Main Results The approach was validated under different conditions, i.e. different types of flexible resources It informs the network planner if additional flexibility would contribute or not to increase the flexibility area 9

10 Lessons Learned Main Results Provides the aggregated active and reactive power flexibility available at the TSO-DSO boundary Computes the operating point expected without using any flexibility Constrain the optimization to different maximum flexibility costs Future Research Work The developed model considered only one point of connection between transmission and distribution networks; To overcome this limitation is necessary to model and integrate a network equivalent for the transmission network; Obtain the flexibility sub-areas that arise when the number of discrete variables with high step lengths increase (OLTCs; reactive power compensators) 10

11 Future Research Work Discrete Variables This figure was obtained through the enumeration of a reduced number of combinations for discrete variables. To overcome this problem is possible to foresee the development of a metaheuristic capable to capture a good representative set of flexibility sub-areas. 11

12 Thank you for your attention João Silva 12