HVDC-WISE D5.3: Tool for reliability and resiliency-oriented expansion planning: Release for public dissemination

This document accompanies the second release of the tools for supporting decision-making in AC/DC grid transmission planning, developed within Task 5.2 of HVDC-WISE. The implementation is consistent with the high-level methodology for HVDC architecture assessment aimed at Reliability & Resilience (R&R)-oriented expansion planning, that was defined in Task 5.1 and further elaborated in the current Task. The methodology and tools aim at filling gaps related to the inclusion of HVDC architectures and extreme events in current planning approaches. The methodology allows to assess and compare different HVDC architectures by computing reliability indices typical of Techno-Economic Analyses (TEA) of transmission expansion, possibly integrated by consideration of enduring consequences of extreme weather events within long-term analyses.

A tool to perform Techno-Economic Analyses (TEA) of transmission projects, including multi-terminal HVDC grids represented with a detailed multi-conductor model within a “nodal OPF” function is described. The modelling methodology and software architecture are described, and a user guide with basic information for installation and execution of the code, written in Julia language, is provided. The OPF function is encapsulated within a Monte Carlo simulation framework that performs hourly simulations of 1-year length, accounting for different “micro-scenarios” meant as evolutions of load demand and renewable generation (where the relevant time series are assumed as available inputs), combined with realisations of availability/unavailability of power system components (computed randomly according to reliability parameters). The generation of time series of component availability in input to the OPF is carried out in Matlab/Octave. An Excel interface has been built to simplify the management of the inputs and outputs of the TEA function. A function written in Julia reads the Excel files and generates the input files in modified Matpower format, needed by the TEA function. Another
function retrieves the text files generated by the TEA function and arrange their contents into Excel tables. For the part written in Julia, the tool builds on, and adapts, previous open-source projects, while the Excel interface and the Matlab code have been developed from scratch. This application is released as an open-source project at https://github.com/HVDC-WISE/HVDCWISE_TEA.jl. The integration into the TEA of the impact of enduring unavailability of multiple components due to extreme events over the long term according to the methodology described in [3] is not presented in this version of the document.

In short, the publicly available tool described in this report is an open-source software (HVDCWISE_TEA) enabling to: 
• Input in a user-friendly format the grid model and the other relevant input quantities
• Generate time series of contingencies resulting from independent outage events and common cause, dependent outage events of both poles of HVDC lines or converters
• Simulate grid operation (electricity market optimization respecting grid constraint), by running multi-period Optimal Power Flows considering hybrid AC/DC grids with multiconductor model of HVDC, and storage
• Perform techno-economic assessment of the grid model that allows computing KPIs to compare grid reinforcement options