The Significance of Modelling Load Diversity in Low Voltage - PowerPoint PPT Presentation

The Significance of Modelling Load Diversity in Low Voltage Distribution Networks Euan McGill 29/11/2018

Presentation Contents • Load Modelling Simplifications in LV Network Simulations • Statistical Analysis on Smart Meter Load Data • Hypothesized Impacts Of Load Modelling Simplifications On Voltage • Statistical Framework For Quantifying The Significance Of Uniform Vs Diversified Load Distribution Within LV Network Analysis • Conclusions & Future work

Load Modelling Within Existing Research • Transformer load uniformly distributed among all downstream premises • When Transformer load is high all houses are heavily loaded • When Transformer load is low all houses are lightly loaded • Is this behavior representative of reality? Representative Urban type LV network GREEN Grid 3

Load Diversity In Smart Meter Data Set Statistical Summary Mean 2.4 kW P5 0.2 kW P50 2.2 kW P95 5.8 kW Distribution of ICP level loads during annual peak load period GREEN Grid

Longitudinal Diversity 1 kW 1 kW 1 kW P Tx = 5 kW Uniform Distribution Φ A 1 kW 1 kW 0.5 kW 0.25 kW 2.5 kW P Tx = 5 kW Diversified Distribution Φ A 0.25 kW 1.5 kW

Across Phases Diversity P Tx = 1 kW 1 kW 1 kW Uniform Distribution Φ C Φ A Φ B Φ B Φ C Φ A 1 kW 1 kW 1 kW P Tx = 0.5 kW 1.5 kW 1 kW Diversified Distribution Φ C Φ A Φ B Φ B Φ C Φ A 1.5 kW 1 kW 0.5 kW

Generalized Case • 3 phase radial feeder • n ICPs per phase • Uniformly spaced • Total Feeder impedance of Z

Voltage Drop Equations - Uniform Load Distribution 𝑣𝑜𝑗 𝑊 𝑆𝑓 𝐹𝑃𝑀 % 𝑣𝑜𝑗 ∙ 𝐽 𝑣𝑜𝑗 ∙ 𝑎 𝑒𝑠𝑝𝑞 𝐵 𝑣𝑜𝑗 𝑣𝑜𝑗 • 𝑊 = 𝑊 = 𝑆𝑓 𝐹𝑃𝑀 % 𝑣𝑜𝑗 ∙ 𝐽 𝑣𝑜𝑗 ∙ 𝑎 𝑒𝑠𝑝𝑞 𝑒𝑠𝑝𝑞 𝐶 𝑣𝑜𝑗 𝑊 𝑆𝑓 𝐹𝑃𝑀 % 𝑣𝑜𝑗 ∙ 𝐽 𝑣𝑜𝑗 ∙ 𝑎 𝑒𝑠𝑝𝑞 𝐷 • 𝐹𝑃𝑀 % 𝐵 = 𝐹𝑃𝑀 % 𝐶 = 𝐹𝑃𝑀 % 𝐷 = 𝐹𝑃𝑀 % 𝑣𝑜𝑗 𝐽 𝑢𝑝𝑢𝑏𝑚 • 𝐽 𝐵 = 𝐽 𝐶 = 𝐽 𝐷 = = 𝐽 𝑣𝑜𝑗 3 𝑣𝑜𝑗 𝑣𝑜𝑗 𝑣𝑜𝑗 • 𝑊 = 𝑊 = 𝑊 = 𝑊 𝑒𝑠𝑝𝑞 𝐵 𝑒𝑠𝑝𝑞 𝐶 𝑒𝑠𝑝𝑞 𝐷 𝑒𝑠𝑝𝑞

Voltage Drop Equations – Diversified loads 𝑒𝑗𝑤 𝑊 𝑆𝑓 𝐹𝑃𝑀 % 𝐵 ∙ 𝐽 𝐵 ∙ 𝑎 𝑒𝑠𝑝𝑞 𝐵 𝑒𝑗𝑤 𝑒𝑗𝑤 • 𝑊 = 𝑊 = 𝑆𝑓 𝐹𝑃𝑀 % 𝐶 ∙ 𝐽 𝐶 ∙ 𝑎 𝑒𝑠𝑝𝑞 𝐶 𝑒𝑠𝑝𝑞 𝑒𝑗𝑤 𝑊 𝑆𝑓 𝐹𝑃𝑀 % 𝐷 ∙ 𝐽 𝐷 ∙ 𝑎 𝑒𝑠𝑝𝑞 𝐷 • 𝐹𝑃𝑀 % 𝐵 ≠ 𝐹𝑃𝑀 % 𝐶 ≠ 𝐹𝑃𝑀 % 𝐷 ≠ 𝐹𝑃𝑀 % 𝑣𝑜𝑗 𝐽 𝑈𝑝𝑢𝑏𝑚 • 𝐽 𝐵 ≠ 𝐽 𝐶 ≠ 𝐽 𝐷 ≠ = 𝐽 𝑣𝑜𝑗 3 𝑒𝑗𝑤 𝑒𝑗𝑤 𝑒𝑗𝑤 • 𝑊 ≠ 𝑊 ≠ 𝑊 𝑒𝑠𝑝𝑞 𝐵 𝑒𝑠𝑝𝑞 𝐶 𝑒𝑠𝑝𝑞 𝐷

Longitudinal & Across Phase Diversity Scaling Factors 𝑒𝑗𝑤 𝑊 𝑆𝑓 𝐹𝑃𝑀 % 𝐵 ∙ 𝐽 𝐵 ∙ 𝑎 𝑣𝑜𝑗 𝑊 𝑆𝑓 𝐹𝑃𝑀 % 𝑣𝑜𝑗 ∙ 𝐽 𝑣𝑜𝑗 ∙ 𝑎 𝑒𝑠𝑝𝑞 𝐵 𝑒𝑠𝑝𝑞 𝐵 𝑒𝑗𝑤 𝑒𝑗𝑤 • 𝑊 = 𝑊 = 𝑆𝑓 𝐹𝑃𝑀 % 𝐶 ∙ 𝐽 𝐶 ∙ 𝑎 𝑣𝑜𝑗 𝑣𝑜𝑗 • 𝑊 = 𝑊 = 𝑆𝑓 𝐹𝑃𝑀 % 𝑣𝑜𝑗 ∙ 𝐽 𝑣𝑜𝑗 ∙ 𝑎 𝑒𝑠𝑝𝑞 𝐶 𝑒𝑠𝑝𝑞 𝑒𝑠𝑝𝑞 𝐶 𝑒𝑠𝑝𝑞 𝑒𝑗𝑤 𝑊 𝑆𝑓 𝐹𝑃𝑀 % 𝐷 ∙ 𝐽 𝐷 ∙ 𝑎 𝑣𝑜𝑗 𝑊 𝑆𝑓 𝐹𝑃𝑀 % 𝑣𝑜𝑗 ∙ 𝐽 𝑣𝑜𝑗 ∙ 𝑎 𝑒𝑠𝑝𝑞 𝐷 𝑒𝑠𝑝𝑞 𝐷 Uniform Voltage Drop Equations Diversified Voltage Drop Equations 𝐹𝑃𝑀 %𝐵 𝐹𝑃𝑀 %𝑣𝑜𝑗 ൗ 𝐽 𝐵 𝐽 𝑣𝑜𝑗 ൗ 𝐿 ෩ 𝐿 ∅ 𝐵 ∅ 𝐵 𝐹𝑃𝑀 %𝐶 𝐹𝑃𝑀 %𝑣𝑜𝑗 𝐽 𝐶 𝐽 𝑣𝑜𝑗 𝐿 ෩ • 𝐿 ∅ 𝐶 • 𝐿 ∅ = = ൗ 𝐿 ෩ ∅ = = ൗ ∅ 𝐶 𝐿 ∅ 𝐷 𝐿 ෩ 𝐽 𝐷 𝐽 𝑣𝑜𝑗 𝐹𝑃𝑀 %𝐷 𝐹𝑃𝑀 %𝑣𝑜𝑗 ൗ ∅ 𝐷 ൗ Across Phase Diversity Factor Longitudinal Diversity Factor

Diversity Scaling Factor Definition • Unique Combined Diversity Scaling 𝑣𝑜𝑗 𝑒𝑗𝑤 𝐿 ∅ 𝐵 ∙ 𝐿 ෩ ∅ 𝐵 ∙ 𝑊 𝑊 𝑒𝑠𝑝𝑞 𝐵 𝑒𝑠𝑝𝑞 𝐵 Factor for each phase 𝑒𝑗𝑤 𝑒𝑗𝑤 𝑣𝑜𝑗 • 𝑊 𝐿 ∅ 𝐶 ∙ 𝐿 ෩ ∅ 𝐶 ∙ 𝑊 𝑊 = = 𝑒𝑠𝑝𝑞 𝑒𝑠𝑝𝑞 𝐶 𝑒𝑠𝑝𝑞 𝐶 𝑒𝑗𝑤 𝑣𝑜𝑗 𝑊 𝐿 ∅ 𝐷 ∙ 𝐿 ෩ ∅ 𝐷 ∙ 𝑊 • 𝑒𝑠𝑝𝑞 𝐷 𝑒𝑠𝑝𝑞 𝐷 K>1 means uniform load distribution underestimates true voltage drop 𝐿 ∅ 𝐵 ∙ 𝐿 ෩ 𝐿 ∅ 𝐵 𝐵 • K<1 means uniform load distribution 𝐿 ∅ 𝐶 ∙ 𝐿 ෩ • 𝐿 = 𝐿 𝐶 = ∅ 𝐶 overestimates true voltage drop 𝐿 𝐷 𝐿 ∅ 𝐷 ∙ 𝐿 ෩ ∅ 𝐷 • Varies with time 𝑒𝑗𝑤 𝑣𝑜𝑗 𝑊 𝐿 𝐵 ∙ 𝑊 𝑒𝑠𝑝𝑞 𝐵 𝑒𝑠𝑝𝑞 𝐵 𝑒𝑗𝑤 𝑒𝑗𝑤 𝑣𝑜𝑗 • 𝑊 = 𝑊 = 𝐿 𝐶 ∙ 𝑊 𝑒𝑠𝑝𝑞 𝑒𝑠𝑝𝑞 𝐶 𝑒𝑠𝑝𝑞 𝐶 • Distribution of [K] can be obtained by 𝑒𝑗𝑤 𝑣𝑜𝑗 𝑊 𝐿 𝐷 ∙ 𝑊 𝑒𝑠𝑝𝑞 𝐷 𝑒𝑠𝑝𝑞 𝐷 analyzing smart meter data

Monte Carlo Method

Monte Carlo Method

Monte Carlo Method

Results 95 th Percentile of K max During Peak Load Periods Vs Number of ICPs

Results 5 th Percentile of K min During Low Load Periods Vs Number of ICPs

Convergence of Results

Conclusions & Future Work • LV network simulations which assume uniform load distribution can result in erroneous voltage drop calculations. • Longitudinal and Across Phase Diversity Scaling Factors were defined to relate the voltage drop equations for the uniform and diversified cases • Results have demonstrated significant underestimations of voltage drop during high load periods where networks typically operate around the lower statutory limit for steady state voltage. • On the contrary overestimations of voltage drop during low load periods where networks typically operate around the upper statutory limit for steady state voltage are also possible. • Impact studies for future scenarios which fail to capture the non-uniformity of ICP level loads may consequently mask over potential steady state voltage violations.

Conclusions & Future Work • In the future, locational clustering of Electric Vehicles and Photovoltaics may result in increased Longitudinal and Across Phase diversity, worsening the extent of the problem described here. • Future work will look to: – Assess the impacts of emerging technologies on Longitudinal and Across Phase diversity – Assess the impacts within real life network topologies (i.e. not purely radial) – Assess the impacts on neutral voltage rise

21 Thank you to our industry members of the Power Engineering Excellence Trust

Load Diversity Definition • Load Diversity describes the coincidence of peak loading among individual consumers • Unlikely that the daily peak demands of individual consumers will coincide • Load diversity is used in planning in order to curb the total capacity requirements of network assets

After Diversity Maximum Demand 𝑂 𝐵𝐸𝑁𝐸 = 1 𝑂 ෍ 𝑄 𝑜 = 𝐵𝑔𝑢𝑓𝑠 𝐸𝑗𝑤𝑓𝑠𝑡𝑗𝑢𝑧 𝑁𝑏𝑦𝑗𝑛𝑣𝑛 𝐸𝑓𝑛𝑏𝑜𝑒 𝑞𝑓𝑠 𝑑𝑣𝑡𝑢𝑝𝑛𝑓𝑠 𝑜=1 𝑂 = 𝑂𝑣𝑛𝑐𝑓𝑠 𝑝𝑔 𝑑𝑣𝑡𝑢𝑝𝑛𝑓𝑠𝑡 𝑗𝑜 𝑏 𝑜𝑓𝑢𝑥𝑝𝑠𝑙 𝑜 = 𝐸𝑓𝑛𝑏𝑜𝑒 𝑝𝑔 𝑢ℎ𝑓 𝑜 𝑢ℎ 𝑑𝑣𝑡𝑢𝑝𝑛𝑓𝑠 𝑏𝑢 𝑢ℎ𝑓 𝑢𝑗𝑛𝑓 𝑝𝑔 𝑜𝑓𝑢𝑥𝑝𝑠𝑙 𝑞𝑓𝑏𝑙 𝑒𝑓𝑛𝑏𝑜𝑒 𝑄 • This type of load diversity is described within this work as Temporal Diversity

Temporal Diversity in Smart Meter Data Impact Of Network Aggregation Scale On ADMD Per Customer

Research Incentives • In New Zealand the penetration of disruptive technologies such as EV’s and residential PV is increasing. • These technologies may significantly alter the load profiles of individual consumers. • The net consequences of which will impact steady state voltages in low voltage networks. • To quantify these impacts within load flow simulations a representative load modelling approach for future scenarios is required. • It is hypothesized that the emergence of these technologies will increase load diversity in low voltage networks. • The significance of accounting for load diversity within LV network modelling thus needs to be investigated.

Equivalent End Of Line (EOL) Load Model Detailed Voltage Drop Model Equivalent EOL load model

Equivalent End Of Line Load Model – Uniform Spacing & Uniform Loading

4 ICP Example Feeder Case ICP Spacing Load distribution 1 Uniform Uniform 2 Uniform Non-Uniform

Impact Of Longitudinal Diversity On EOL % Case 1 ~25% increase in voltage drop Case 2 Equivalent EOL load model Detailed Voltage Drop Model