RDZ-110 Two-column centre-break disconnector, rated voltage 110 kV

RDZ-110 disconnectors are intended for isolating and re-connecting de-energised sections of an electrical circuit operating at up to 110 kV, as well as for earthing (grounding) those de-energised sections by means of earthing switches integrated with the disconnectors. Versions are available as single-pole, two-pole and three-pole. The pole coupled to the operating mechanism is the driving pole. Operating mechanisms are intended for disconnector operation. Rotation of the main-circuit and earthing-switch shafts is performed manually with PRG-6 mechanisms or by a PD-14 motor drive.
The disconnectors are manufactured for outdoor service in a cold/moderate climate (installation category 1) in accordance with EN/IEC 60721-3-4, with the following limits:
– altitude up to 1000 m;
– upper service temperature of ambient air +40 °C;
– lower service temperature of ambient air -60 °C;
– wind speed not more than 40 m/s with no ice and not more than 15 m/s with ice accretion up to 20 mm;
– average annual relative humidity 80% at +15 °C;
– maximum wind pressure 700 Pa (corresponds to 34 m/s) without ice;
– maximum wind pressure 140 Pa (corresponds to 15 m/s) with ice accretion up to 20 mm.
Conductor tension in the horizontal plane including wind effects - not less than 1000 N.
Dielectric withstand performance complies with the requirements for the 110 kV class in IEC 62271-1 and IEC 62271-102. Creepage distance of the external insulation for standard porcelain insulators per IEC 60815:
– for pollution level I - not less than 200 cm;
– for pollution level II - not less than 250 (280) cm.
On request, RDZ units may be supplied on polymeric insulators with creepage not less than 250 (280) cm.
Mechanical endurance of the disconnectors - 5000 operating cycles (open/close).

Technical data

Rated voltage, kV	110
Maximum system voltage, kV	126
Rated current, A	1000; 2000; 3150
Rated short-time peak withstand current (electrodynamic), kA	80; 100; 125
Rated short-time withstand current (thermal), kA	31.5; 40; 50
Duration of short-time withstand current, s – main blades – earthing switches	3 1
Creepage distance of external insulation, cm, not less than	200
Conductor tension in the horizontal plane incl. wind, N, not less than	800; 1000
Minimum clearances in air from live parts to various elements, mm: – from live parts to earthed structures; – between live parts of different phases; – across the open contacts of one pole	– 900 – 1000 – 900

Application and use

RDZ-110 is a two-column, outdoor centre-break disconnector with rotating post insulators and a central isolating gap. It provides a visible isolating distance and electrical isolation of the disconnected network section, enabling safe maintenance in 110 kV switchyards. Typical applications:

110 kV AIS outdoor switchyards of utilities and industrial plants;
Switching of transformer connections, overhead and cable lines, bus bridges and bus sections;
Switching of transformer no-load currents and line charging currents (within permissible limits), plus earthing of disconnected sections by built-in earthing switches;
Use in automatic bus transfer schemes, bypasses and maintenance jumpers;
Equipping new and modernised substations with unified drives, interphase shafts and standardised connection interfaces.

Thanks to its modular design, RDZ-110 adapts to the switchyard layout: installation on foundations or steel structures, on line portals or bus galleries. Recommended wherever frequent off-load operational switching, high mechanical reliability and clear indication of contact position are required.

Service conditions

The standard configuration is designed for outdoor service per EN/IEC 60721-3-4 (installation category 1). The design accounts for the wind and icing loads stated above as well as long-term exposure to solar radiation, rain and dust. Mechanism parts are made of corrosion-resistant steels and aluminium alloys with protective coatings; bearing pairs are sealed, which increases service life and reduces maintenance. On request, versions are available:

for areas with higher pollution severity (increased creepage distance, hydrophobic coatings);
with polymeric insulators (silicone rubber) for improved performance under wet and polluted conditions;
for extended temperature ranges and special climatic factors (low-temperature lubricants, anti-icing solutions in drives);
for zones with higher wind loads and specific corrosion-protection requirements.

Arrangement and design features

RDZ-110 belongs to the class of two-column centre-break disconnectors. Each phase (pole) has two support post insulators mounted on a common base frame. The rotation axis is at the base; during opening/closing the posts rotate synchronously in the horizontal plane from the driving mechanism via linkages and an interphase shaft. Main assemblies:

Base frame. Rigid welded structure with anti-corrosion coating. Prepared pads and holes for the drive, interphase shaft and earthing switches; alignment devices provided for on-site adjustment.
Support insulators. Porcelain (standard) or polymeric (option) with normalised creepage distance for the selected pollution level. The current-carrying blade is mounted on the top of the post.
Current path. Pivoting blade with multi-lam contact fingers and spring-loaded pressure system ensuring stable contact force and low resistance. Connections to the fixed contacts by flexible connectors/straps to accommodate thermal and mechanical movement.
Earthing switch(es). Installed on the fixed or moving side, with its own shaft and interlocks preventing mal-operation.
Operating mechanism. Manual PRG-6 or motor drive PD-14 with gearbox, limit switches, position signalling microswitches and mechanical position indicator “ON/OFF/EARTHED”. Integration with protection/SCADA via dry contacts or terminal blocks.
Interphase shaft and linkages. Provide synchronous rotation of all poles, with turnbuckle couplings for precise angular and timing adjustment. Sealed bearing units are applied.

The design emphasises maintainability: good access for inspection, removal of blades and contact jaws without dismantling the frame, and unified fastener sizes. Left/right (drive orientation) and mirror-image arrangements are available for convenient bay layout.

Safety and interlocking

Safe operation is ensured by mechanical and electrical interlocks that prevent closing the earthing switch with the main contact closed, and conversely, prevent closing the main circuit with the earthing switch engaged. Drive units are equipped with flag locks and padlock holes to block operations during work. Standard supply includes:

mechanical interlock rod between main-circuit and earthing-switch shafts;
limit switches at the end positions “ON/OFF/EARTHED” for substation control signalling;
visible isolating distance simplifying work permits;
provision for key interlocks (Castell-type and equivalents) to project requirements.

Versions and options

The RDZ-110 range covers current ratings of 1000; 2000; 3150 A and configurations with 0/1/2 earthing switches per pole, as well as options for insulation type and operating mechanisms. A summary of typical options is given below.

Parameter	Base configuration	Options
Rated current, A	1000	2000; 3150
Earthing switch(es) per pole	0 or 1	2 (double-blade); selectable mounting side
Insulation type	Porcelain, pollution level I/II	Polymeric, increased creepage
Operating mechanism	Manual PRG-6	PD-14 motor drive, position signalling, remote control
Environmental classification	EN/IEC 60721-3-4 (outdoor)	Enhanced outdoor design, anti-icing solutions, reinforced corrosion protection
Contact system	Lamellar fingers, spring pressure	High-wear fingers, tin/silver-plated contact surfaces

Compliance with standards

RDZ-110 disconnectors are designed and manufactured in line with applicable international standards specified in the project documentation for each supply. Principal standards:

IEC 62271-102 - High-voltage switchgear and controlgear. Alternating-current disconnectors and earthing switches;
IEC 62271-1 - High-voltage switchgear and controlgear. Common specifications;
EN/IEC 60721-3-4 and EN/IEC 60721-3-3 - Classification of environmental conditions (stationary use at non-weather-protected / weather-protected locations);
IEC 60815 (series) - Selection and dimensioning of high-voltage insulators for polluted conditions.

Advantages for designers and operators

Reliable visible isolating distance and interlocking system - personnel safety and equipment protection;
Unified mechanisms and linkages - simplified spares and maintenance;
Flexible modification by current, insulation and earthing - project adaptation without changing the overall layout;
Compatibility with common centre distances and connection dimensions - reduced effort for retrofits;
Position signalling ready for integration into SCADA/automation.

Scope of supply

Disconnector poles (3 pcs for three-pole version) on a base frame or loose - per specification;
PRG-6/PD-14 operating mechanism(s), interphase shaft, full set of linkages and joints;
Earthing switches according to selected configuration;
Flexible connectors and terminal pads set;
Operating documentation: data sheet, operating manual, installation maps, records, test reports.

We offer documentation packages for manufacturing RDZ-110 disconnectors:

– Preliminary technical documentation for tender participation for RDZ-110 disconnector manufacture. We will prepare the information required to assess manufacturability against tender requirements and to complete enquiry sheets.
– Detailed drawings, 3-D models and other documentation for manufacturing RDZ-110 disconnectors at your facility. If you do not plan in-house production of parts and assemblies, we will assist in outsourcing to suitable suppliers. Final assembly and installation can be carried out at your site.
– All documentation can be adjusted, if required, to the project specification and to your plant’s technological capabilities.
– If equipment from another manufacturer is installed at the substation, we will prepare documentation for manufacturing compatible equipment to complement it.

Engaging contractors, equipment manufacturers and investors

We are open to cooperation with machine-building plants, assembly sites, insulator and steelwork manufacturers, as well as investors interested in localisation of medium-voltage switching equipment production. Under partnership we provide:

a complete RDZ-110 design documentation package adapted to existing capacities and processes;
technological documentation (routes, tooling lists, inspection cards);
spare-parts lists and standard items (fasteners, bearings, standard components) readily available on the market;
methodical support during ramp-up and initial deliveries;
where required - selection and support of cooperation on assemblies (contact systems, drives, tie-rod joints).

Why work with us

– No need to maintain a large team of highly qualified engineers: you receive a complete documentation set for the product that can be handled by an engineer of average qualification.
– No need to build prototypes: our experience enables direct launch of serial production.
– Working to our documentation, your specialists will receive consultation on all aspects of RDZ-110 disconnector manufacturing.