The lower power quality and shrinking inertia of renewable generation puts new demands on monitoring, controlling and balancing energy flows in the electricity grid. This calls for new high-voltage (HV) metrology solutions to support the HV manufacturing industry. The recently started EU project ’ENSURE’ is addressing this need by developing new HV measurement technology in four areas: wideband live connectable current or voltage sensors to monitor and calibrate substation instrumentation; new capability for determining the losses in power transformers caused by grid harmonics; new methods for loss determination in HVAC cables; and new partial discharge monitoring techniques for fault detection and localization in HVDC cables.