arXiv subjects

Peter Pudney

Publications and source records attributed to Peter Pudney.

3 recordsLinked to original sources

arXiv2026

Optimal driving strategies for a fleet of trains

In order to manage electricity transmission and distribution it is now common practice for system operators to offer financial incentives that encourage large consumers to reduce energy usage during designated peak demand periods. For train operators on large rail networks it may be profitable -- with selected individual journeys -- to reduce energy usage during peak times and increase energy usage at other times rather than simply minimizing overall energy consumption. We will use classical methods of constrained optimization to find optimal driving strategies for a fleet of trains subject to limits on total energy consumption during specified intermediate time intervals but with no change to individual journey times. The proposed strategies can be used by a large rail organisation to reduce overall operating costs with only minimal disruption to existing schedules and with no changes to important departure and arrival times.

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arXiv2025

Impact Analysis of Optimal EV Bi-directional Charging with Spatial-temporal Constraints

The growth in Electric Vehicle (EV) market share is expected to increase power demand on distribution networks. Uncoordinated residential EV charging, based on driving routines, creates peak demand at various zone substations depending on location and time. Leveraging smart charge scheduling and Vehicle-to-Grid (V2G) technologies offers opportunities to adjust charge schedules, allowing for load shifting and grid support, which can reduce both charging costs and grid stress. In this work, we develop a charge scheduling optimization method that can be used to assess the impact of spatial power capacity constraints and real-time price profiles. We formulate a mixed-integer linear programming problem to minimize overall charging costs, taking into account factors such as time-varying EV locations, EV charging requirements, and local power demands across different zones. Our analysis uses real data for pricing signals and local power demands, combined with simulated data for EV driving plans. Four metrics are introduced to assess impacts from the perspectives of both EV users and zones. Results indicate that overall EV charging costs are only minimally affected under extreme power capacity constraints.

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arXiv2021

Optimal driving strategies for a fleet of trains on level track with prescribed intermediate signal times and safe separation

We propose an analytic solution to the problem of finding optimal driving strategies that minimize total tractive energy consumption for a fleet of trains travelling on the same track in the same direction subject to clearance-time equality constraints that ensure safe separation and compress the line-occupancy timespan. We assume the track is divided into sections by a set of trackside signals at fixed locations. For each intermediate signal there is a signal-location segment consisting of the two adjacent sections. Successive trains are safely separated only if the leading train leaves each signal-location segment before the following train enters. The fleet can be safely separated by a complete set of clearance times and associated clearance-time inequality constraints. The problem of finding optimal schedules with safe separation has been solved for two trains but for larger fleets the problem rapidly becomes intractable as the number of trains and signals increases. The main difficulty is in distinguishing between active equality constraints and inactive inequality constraints. The curse of dimensionality means it is not feasible to check every different combination of active constraints, optimize the corresponding prescribed times and calculate the cost. Nevertheless we can formulate and solve an alternative problem with active clearance-time equality constraints for successive trains on every signal-location segment. We show that this problem can be formulated as an unconstrained convex optimization and we propose a viable solution algorithm that finds the optimal schedule and the associated optimal strategies for each train. Finally we use our solution to find optimal schedules for a busy inter-city shuttle service.

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