CLIENT — NATIONAL TRANSMISSION SYSTEM OPERATOR, NORTHERN EUROPE TIMELINE 2022—2025 STATUS — IN OPERATION REGULATOR-AUDITED
9,000+
SUBSTATIONS UNDER REAL-TIME CONTROL
180 MS
STATE ESTIMATION, FROM 4.2 S
99.997%
CONTROL-PLANE AVAILABILITY
0 MIN
UNPLANNED DOWNTIME DURING CUTOVER
01 / PROBLEM

A GRID PAST ITS DESIGN ENVELOPE

The control stack dated to the 1980s: nightly batch state estimation, switching plans built by hand, and a vendor that had ended support a decade earlier. Renewable intake had pushed grid dynamics past what the system was designed to see — operators were flying a modern grid on yesterday's instruments.

02 / APPROACH

SHADOW, THEN CUT OVER — ELEVEN TIMES

We instrumented the legacy estate in place and ran the new control platform in shadow mode for fourteen months, reconciling every state estimate against the old system's. Migration went region by region — eleven cutovers, each reversible within minutes, none reversed. Operators trained on the live platform, not simulations.

14 MONTHS PARALLEL SHADOW OPERATION
STATE ESTIMATION RECONCILED NIGHTLY AGAINST LEGACY
EVERY CUTOVER REVERSIBLE IN UNDER 4 MINUTES
03 / OUTCOME

AUDITED, OPERATED, EXTENDED

State estimation now runs in 180 milliseconds against 4.2 seconds before; manual interventions are down 31%. The national regulator audited the platform in 2025 and cleared it without findings. Esnicole operates the system jointly with the client under a 10-year agreement — the outcome we consider the real deliverable.

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