Substation renovation

Substation renovation encompasses the technical, structural, and organizational upgrading of existing switchyards and transformer stations during ongoing grid operation. It ranges from the selective deconstruction of old concrete foundations to the renewal of cable routes and the adaptation of transformer sumps and switchgear building structures. Because of the proximity to live components, strict emission requirements, and confined work areas, low-vibration, low-spark, and precise methods are preferred. Tools and systems from Darda GmbH such as precision concrete crushers, rock and concrete splitters, hydraulic power packs, combination shears, multi cutters, steel shears, and tank cutters are used in this context to enable selective deconstruction with high control and minimal impact on ongoing operations.

Definition: What is meant by substation renovation

Substation renovation refers to the planned repair, modernization, and partial conversion of substations (AIS/GIS), including their concrete and steel structures, cable routes, foundations, transformer sumps, outgoing feeders, and ancillary buildings. The aim is to extend service life, adapt to current technical requirements and safety standards, and optimize operation, inspection, and disposal. Core tasks include selective concrete demolition, separation of metallic components suitable for disassembly, gutting of switchgear buildings, and the restoration or new construction of the structures required for grid operation.

Specific requirements in substations: safety, emissions, and working within existing assets

Renovation work in substations is often carried out while essential grid functions remain in service. This leads to specific requirements for work methods and equipment:

• Low vibration: Minimization of vibrations to protect sensitive equipment and foundations, for example by using concrete crushers or rock and concrete splitters.
• Low-spark and low-dust working: Cold cutting methods, low-dust breaking and splitting, localized water misting for dust suppression.
• Electrical safety: Work near live components requires coordinated permits, defined approach distances, and clear construction phase planning.
• Construction logistics: Confined work areas, defined crane and travel paths, load distribution on gravel surfaces, temporary supports.
• Environmental and water protection: Handling oil-affected areas (e.g., at transformer sumps), separate collection of contaminated construction materials, sealed working in sensitive zones.

Typical work steps in substation renovation

1. As-built survey and planning: Structural diagnostics, rebar locating, concrete compressive strength, vibration and noise concepts, construction phases and switching plans.
2. Strip-out and cutting: Removal of interior finishes, creation of openings, dismantling of non-load-bearing components with concrete crushers; cutting of cable trays with steel shears or multi cutters.
3. Selective concrete demolition: Removal of bearing edges, foundation shafts, and cable-duct walls; use of rock and concrete splitters for controlled crack formation and separation.
4. Metal dismantling: Separating steel columns, lattice girders, and embedded parts using combination shears or steel shears; tank cutters for vessels and closed hollow bodies in a cleared, released condition.
5. Rebuild and upgrading: Concrete additions, reprofiling, new cable routes, adaptations to transformer sumps, installation of new components.
6. Quality assurance: Dimensional control, surface inspection, documentation of separation and demolition methods, and disposal evidence.

Selective concrete demolition: methods and equipment selection

When deconstructing foundation heads, cable ducts, switchgear building slabs, or mast foundations within existing assets, precise, controlled, and low-damage methods are essential. Two methods have proven particularly effective:

Concrete crushers: controlled removal without impact energy

Concrete crushers from Darda GmbH grip components from both sides, split, and crush concrete without a percussion mechanism. Benefits in the substation:

• Low vibration and thus protection of sensitive equipment.
• Targeted exposure of reinforcement for single-grade separation.
• Good accessibility in confined areas, for example at cable ducts or wall bases.
• Reduced edge spalling and clean edges for subsequent concrete repairs/additions.

Rock and concrete splitters: splitting instead of striking

Rock and concrete splitters from Darda GmbH use hydraulic splitting cylinders in drilled holes. For specific geometries, Rock splitters are selected to segment sections efficiently. They create defined cracks and release massive components in controllable blocks:

• Quiet and low-vibration, suitable for work near in-service plant.
• Effective on heavy sections such as transformer sump edges, mast foundations, or massive cable-duct walls.
• Low secondary damage to adjacent components and lines.

Hydraulic power packs: power supply and controllability

Hydraulic power packs from Darda GmbH, together with compact hydraulic power units, supply concrete crushers and splitting cylinders with the required power. Important are torque-stable, finely controllable systems that allow long hose lines at a safe distance from live parts while keeping noise levels low.

Metal dismantling: cutting, shearing, opening

Steel components, cable trays, covers, and vessels are preferably cut cold and with reduced sparking in substations:

• Steel shears for profiles, sheets, and lattice structures in the switchyard.
• Combination shears for varying cross-sections when demolition and cutting tasks coincide.
• Multi cutters for cable bundles, pipelines, and thin-walled metals.
• Tank cutters for opening and segmenting empty, released vessels or closed hollow bodies, such as covers or collection devices. Work is carried out only after appropriate clearance measurements and generally recognized safety measures.

The selection of tools depends on material grade, cross-section, residual stress, and the required component separation, with emission minimization having top priority.

Planning, structural analysis, and construction phases

Construction phase planning in substations coordinates grid switching, permits, load relief, and temporary protections. Key points:

• Structural analysis: Sequencing of cuts and splitting operations to avoid unintended load redistribution.
• Temporary props and hangers: Protection of slab fields, cable bridges, and openings in switchgear buildings.
• Vibration and crack monitoring: Monitoring points on sensitive components; selection of low-vibration methods (concrete crushers, splitters).
• Logistics in special deployment: Restricted access, low ground pressures, modular tools, and compact hydraulic power packs.

Environmental and resource protection

In the switchyard, strict requirements apply to soil and water protection. Construction materials must be collected separately and disposed of properly. Typical measures:

• Material flow management: Separation of concrete, reinforcing steel, cables, coated metals, and potentially contaminated materials.
• Dust and noise reduction: Localized wetting, wind-adapted working, quiet cutting and splitting methods.
• Liquids management: Protection against entry into transformer sumps and drainage; sealed working areas and catchment devices.

Legal requirements must be reviewed on a project-specific basis; compliance with relevant provisions is ensured in coordination with the client and the supervisory authorities.

Working near live plant: distances, permits, organization

Work steps are coordinated with plant operations. This includes permits, lockouts, protective grounding, defined approach distances, and the selection of suitable tools. Low-vibration and low-spark methods increase process safety and reduce interface risks.

Method combination and workflow control

Frequently, a component is first segmented into blocks with rock and concrete splitters, which are then further reduced with concrete crushers. Metal inserts are separated with steel shears or combination shears. This combination helps minimize crane times, dust generation, and noise while increasing single-grade separation during removal.

Quality assurance and documentation

Quality assurance includes component verifications (dimensions, flatness, freedom from cracks), test reports for concrete additions, and comprehensive documentation of demolition and separation processes. For the operator, traceable, image-supported reports and material flow evidence are essential.

Applications of Darda GmbH tools in the substation

• Concrete demolition and special deconstruction: Concrete crushers for slab edges, column heads, and cable-duct walls; rock and concrete splitters for massive foundations and transformer sump areas.
• Strip-out and cutting: Multi cutters and combination shears for interior fit-out, cable trays, and thin-walled metals; handy concrete crushers for openings and breakthroughs.
• Special deployment: Compact hydraulic power packs and lightweight attachments when low ground pressures, low emissions, and tight space conditions prevail.

Practice-oriented details in substation renovation

Foundation heads and bearings

Targeted opening of bearing edges and brackets with concrete crushers reduces edge spalling and facilitates connection reinforcement. Splitters release deep sections without percussive action.

Cable ducts and shafts

Cover and wall panels are removed segment by segment. Metallic inserts are sheared with reduced sparking; concrete portions are reduced with concrete crushers to protect cables.

Switchgear building and ancillary buildings

Strip-out is carried out in sections. Wall openings are created in a controlled manner; cut sequences consider structural behavior and installations. Low-vibration methods protect adjacent components.