Category: (Near) conventional solutions
Grid Requirement tackled
- Insufficient (transport) capacity on existing high-voltage lines / corridors because of DRES roll-out leads to connection delays and high redispatch costs.
- Building new lines or installing higher power poles instead of existing ones is a complex and expensive process, which is subject to official approval procedures (permitting).
Approach & solution
- Replacing conventional conductors with high temperature low sag conductors (HTLS) where possible on the existing power poles. They can withstand higher currents and operating temperatures of up to 210°C without sagging too close to the ground.
- Different types of HTLS (definition see CIGRE) already in use at E.ON DSOs.
- Type 2 HTLS (e.g. ZTAHAC) are used if the height of the existing lines above the ground is already sufficient for operating conventional lines at 80°C. The ZTAHAC have the advantage that the handling, fittings and interference suppression are similar to type 1 HTLS already in use for many years which implies that no additional training and special materials need to be provided.
- Type 3 HTLS (e.g. ACR) are used in case the lines have only a small ground clearance.
- It should be noted that HTLS are generally more expensive than conventional conductors and they lead to higher energy losses due to the high temperatures. Therefore, their use should be limited to grid areas, where their benefits outweigh their costs.
Benefits
- Providing the maximum of capacity in existing corridors while using existing poles. All conductor changes that are planned at Westnetz will create an additional ~6,500 MVA of capacity in the next three years and at Bayernwerk additional ~10,000 MVA will be created until 2030 according to their respective DNDP.
- Building new lines or upgrading existing ones with higher power. Avoiding or minimising the need for new permitting procedures in the upgrading case.
- Increased hosting capacity for DRES.
- Less redispatch interventions, which is a main benefit that is currently not incentivized.