An Asciidoctor extension that renders protection-relay time-current grading studies written in the tc-curves language (.ptc source) — the @openpowershift/time-current-grading-language npm package — into SVG or PNG at conversion time. SVG output is vector and embeds cleanly in asciidoctor-pdf; PNG rasterisation ships with the tc-curves package itself, so no extra native dependency is needed. Format, scale, theme, the sheet to draw and error handling are controlled with AsciiDoc attributes.