Beneficiaries

• Consumers
• Distributors

What are high voltage stresses?

Voltage ranges must be respected for all electrical power equipment to avoid damage or premature wear. Normal voltage ranges are therefore defined and contracted between RTE and its customers.

For several years, overvoltage events, also known as high voltage stresses, have been a focus of attention for the operation of the electric power system. There are multiple cause factors cumulating in a structural way: increased generation directly connected to distribution systems, increased use of underground cables, changes in final energy consumption with new household appliances, etc.

These overvoltages occur spring to autumn and are most often observed during off-peak night and afternoon hours when electricity consumption is lowest.

They can cause premature wear or potential equipment degradation with consequences on electricity quality. Their impacts are detailed in the RTE reliability report.

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Levers for managing overvoltage

To address these issues, RTE has committed significant investments through the installation of equipment (coils) in substations to reduce grid voltage.

In addition, a revaluation of the financial incentives of market players contributing to high voltage constraints has been incorporated into the TURPE.

On a daily basis, RTE also coordinates with all of the power system players to implement the necessary measures, such as:

• Actions on the transmission systems to reduce voltage: Use of inductors and disconnection of network elements.
• Requirements of generators connected to the transmission system: Use of voltage ancillary services provided by generation units connected to the grid and use of groups with  synchronous compensators
• Requirements of industrial customers & distributors: In addition to the tariff model, request to open installed capacitors
• Requirements in consultation with distribution system operators of connected power producers: implementation of the levers available by the power producers connected to the distribution systems. A consultation is underway to define the terms and conditions for the contribution of HV-A-connected generators to the management of high voltage on the public transmission system.

TURPE 7 and reactive energy

Upon the entry into force of TURPE 7 on 1 August 2025, the pricing of reactive energy injected by distribution system operators (DSOs) connected to the public transmission system is evolving as follows:

• Increase in the pricing coefficients applied to high-voltage exceedances for DSOs, in order to better reflect the costs incurred on the public transmission system.
• Adjustment of the “high-voltage” pricing zone, to more effectively target the primary substations that contribute most to high-voltage constraints and to encourage the activation of existing levers.

The pricing of reactive energy absorbed (low-voltage) by DSOs remains unchanged.

In addition, since 1 April 2026, a new high-voltage pricing (low season) has been introduced for MV (HTA) customers. Indeed, MV networks are experiencing overvoltage during periods of low demand (low season) due to changes in the power system.
This change in the tariff component is intended to increase accountability among MV stakeholders and reduce overvoltage situations.

To guide its customers, RTE provides the Be notified when you exceed your reactive power consumption service. Customers subscribed to this service will be alerted by email of potential reactive energy overruns from the start of the current month, depending on the calculated current period, for one connection point.

Reference documentation

• View RTE’s reliability reports
• Discover the page Understanding the public transmission system access tariff (TURPE)

Contact(s)

For any questions, please contact your usual account manager.

Additional information

Discover the service Be notified when you exceed your reactive power consumption.