RDZ-150 Two-Column Disconnector, rated voltage 150 kV

RDZ-150 type disconnectors are intended for establishing and breaking de-energized sections of an electrical circuit energized up to 150 kV, as well as for earthing (grounding) the isolated sections by means of earthing switches integral to the disconnectors. The disconnectors are available in single-pole, two-pole and three-pole versions. The pole to which the operating mechanism is connected is the driving pole. Operating mechanisms are designed to operate the disconnectors. Rotation of the drive shafts of the main circuit and the earthing switch is performed manually (PRG-6 operating mechanism) or by motor drive (PD-14).
The disconnectors are manufactured for outdoor installation in environmental conditions compliant with EN/IEC 60721-3-4 (outdoor), formerly UHL1, with the following limits:
- altitude not exceeding 1000 m a.s.l.;
- upper service ambient temperature +40 °C;
- lower service ambient temperature -60 °C;
- wind speed up to 40 m/s with no ice, and up to 15 m/s with rime ice thickness up to 20 mm;
- annual mean relative humidity 80% at +15 °C;
- maximum wind pressure 700 Pa (equivalent to 34 m/s) with no ice;
- maximum wind pressure 140 Pa (equivalent to 15 m/s) with ice crust up to 20 mm on surfaces.
Horizontal conductor tension including wind effect - not less than 1000 N.
Dielectric strength of insulation meets the requirements for 150 kV class disconnectors in accordance with IEC 62271-1 and IEC 62271-102. The creepage distance of external insulation for standard porcelain post insulators per IEC 60273/IEC 60815 is as follows:
- for pollution class I - not less than 270 cm;
- for pollution class II - not less than 340 (390) cm.
On request, RDZ units can be supplied on composite (polymer) insulators with creepage distance not less than 340 (390) cm.
Mechanical endurance of the disconnectors - 5000 operating cycles (close-open).

Technical data

Rated voltage, kV	150
Highest system voltage, kV	170
Rated current, A	1000; 2000
Rated peak withstand current (dynamic), kA	100
Rated short-time withstand current, kA	40
Rated duration of short-time current, s - for main blades - for earthing switches	3 1
Minimum creepage distance of external insulation, cm	200
Horizontal conductor tension incl. wind, N, not less	800; 1000
Minimum clearances in air from live parts to various elements, mm: - to earthed structures; - between live parts of different phases; - across the open contacts of one pole	- 1300 - 1400 - 1300

Purpose and application

RDZ-150 is a two-column, outdoor, center-break disconnector intended to provide a visible isolating gap in circuits of the 110–150 kV class when no load current is present. The device enables safe maintenance and operational switching in medium-voltage substations, provides solid earthing of isolated sections when equipped with a fixed earthing switch, and serves as a layout element in air-insulated switchgear (AIS) yards at 110/150 kV.

Typical applications: bay positions in AIS 110/150 kV (gantry and portal layouts); line terminations for 110–150 kV overhead lines on end and through portals; bus sectioning, bypass and maintenance jumpers; isolating of transformers, autotransformers and reactors on the HV side with no load; temporary isolation and earthing of connections to switching and measuring equipment (CTs, VTs, surge arresters) during service. The design is intended for outdoor service per EN/IEC 60721-3-4 with direct exposure to solar radiation, wind and ice loads.

For utilities operating transmission and distribution substations, RDZ-150 is a baseline no-load switching device complementing circuit breakers (oil, SF₆, vacuum) and providing scheme flexibility: visible isolation, safe earthing and operational separation of equipment. In retrofit projects, RDZ-150 helps standardize portal layouts, reduce spare-parts variety and achieve the required clearances for the 150 kV level without rebuilding foundations.

Service conditions

The disconnector is designed for year-round outdoor service. The operating temperature range corresponds to EN/IEC 60721-3-4; adaptation is available for areas with increased salt and industrial pollution (coastal zones, cement/chemical/metallurgical plants) by increasing total creepage distance and/or applying composite hydrophobic insulation. For altitudes above 1000 m a.s.l., insulation distances may be corrected by design. Structural elements are rated for wind and ice loads typical for these environmental categories, as well as for moderate seismic influences as specified by the substation project.

Pollution environment: classes I–II in the standard version on porcelain post insulators; for class III (heavy pollution) and for strong saline fog areas, a version on composite insulators with increased creepage distance and optimized shed profile is recommended. In dusty or salty conditions, periodic inspection and, when required, washing of insulators should be performed per preventive maintenance procedures. Foundations are arranged to provide drainage and runoff of storm water.

Layout and design features

RDZ-150 is a center-break, two-column device: the conducting blade, when closed, bridges the two insulator columns to form a continuous current path. Each column is a support/bearing insulator on a galvanized steel frame. Rotating joints use sealed bearings with anti-corrosion protection; hinges are protected from dust and moisture. Current-carrying parts are made of copper/aluminum sections with silver- or tin-plated contact surfaces to ensure low contact resistance and high thermal withstand under short-circuit currents.

The contact system is a sliding-pressure type with spring loading that self-compensates thermal and vibration effects. Corona rings and grading elements (by design) are provided to reduce local electric-field stress in the 110–150 kV range. Connection points to conductors/busbars are universal: flexible shunts, drilled pads to suit site hole patterns, and standard cable lugs may be fitted. The configurable layout allows poles to be oriented along or across the portal, accounting for actual interphase distances and clearances to earthed structures.

An earthing switch (if provided) is mounted on one side of the pole and mechanically interlocked with the main blade. The linkage uses adjustable rods to synchronize phases (for three-pole versions) and achieve the required rotation angles. Position indication “Closed/Open/Earthed” is provided at the operating mechanism; auxiliary microswitches may be installed for remote indication in protection & control / SCADA schemes.

Load-bearing frames and aluminum/steel parts are hot-dip galvanized and/or powder-coated for long-term corrosion protection. Baseframe stiffness provides torsional stability against wind forces acting on the conductor and blade as specified in “Service conditions”. Standardized base bolt patterns simplify adaptation to existing AIS 110/150 kV portal foundations. Interphase tie-rods and operating shafts are supplied to synchronize three poles with one mechanism (for three-pole execution) or to allow independent mechanisms per pole as required.

Key assemblies	Function and features
Rotating insulator columns	Provide rotation of the contact blade; sealed bearing supports; corrosion protection.
Contact blade and jaws	Silver/tin-plated surfaces; spring pressure; low contact resistance.
Earthing switch	Mechanical interlock with main blade; ensures safe earthing of the isolated section.
PRG-6 / PD-14 drive	Manual or motorized operation; provision for limit switches and remote signalling.
Corona rings (by design)	Reduce local field stress and corona losses at 110–150 kV.

Safety and interlocks

Personnel safety is ensured by design and procedural measures. Interlocks prevent closing the earthing switch when main contacts are closed, and prevent closing the main blade when the earthing switch is closed. Mechanical position indicators and latching devices suitable for lock-out/tag-out (LOTO) can be mounted on the drive. On request, key interlocks between devices (e.g. with a circuit breaker or adjacent disconnectors) are implemented, as well as electrical interlocks via drive auxiliary contacts.

The design provides sufficient rigidity of the contact system and resistance to electrodynamic forces under short-circuit conditions for the 150 kV level; the blade is secured against rebound during operation. Guards on rotating drive parts and travel stops ensure injury prevention.

Versions and options

RDZ-150 is supplied in several configurations to suit specific layout and service conditions. Available as single-, two- and three-pole sets; with or without earthing switch; on porcelain or composite insulators; with manual or motor drive; with outdoor control cabinets for integration into SCADA/automation systems. Options include choice of interphase spacing, blade rotation relative to the portal direction, terminal pad orientation, and use of flexible shunts/bus transitions.

Version	Description	Typical application
Single-pole	One pole with operating mechanism; three units can be synchronized by interphase tie-rod.	Retrofits on existing foundations; non-standard portals.
Three-pole synchronized	Three poles with a common drive, interphase rods and shafting.	Bus sectioning, line and power transformer bays.
With earthing switch	Earthing blade on one side with mechanical interlock.	Maintenance with visible earthing of the isolated section.
Porcelain / Composite	Choice of insulation and creepage distance for pollution classes I–III.	Standard / polluted areas, coastal zones, industrial sites.
PRG-6 / PD-14 drive	Manual or motorized; with limit switches and remote indication.	Operational switching, SCADA integration, remote control.

Standards compliance

RDZ-150 disconnectors are designed and manufactured in line with internationally recognized standards for medium-voltage switchgear. Key references include: IEC 62271-1 (common specifications), IEC 62271-102 (AC disconnectors and earthing switches), IEC 60815 (selection of insulators for polluted conditions), IEC 60273 (characteristics of post insulators for outdoor/indoor service), and EN/IEC 60721-3-4 (environmental conditions - outdoor). National equivalents and corporate specifications can be applied on request.

Engaging contractors, manufacturers and investors

We invite cooperation with design and construction firms, electrical equipment manufacturers and potential investors interested in localizing production of disconnectors for the 110–150 kV range. We provide a manufacturing documentation package tailored to the partner’s capabilities, support series launch, offer technology assistance for parts fabrication and assembly, and train personnel. Subject to separate agreement we can supply assemblies (contact system, insulators, drives, tie-rod and shaft systems) and provide author’s supervision at the customer’s site during installation and commissioning.

Documentation offered (drawings, 3D models, CAD)

Upon request we provide: general assembly drawings, bills of materials, detail and welded-assembly drawings, kinematic and interlock schemes, manuals and operation instructions. Available formats: AutoCAD (DWG/DXF), SolidWorks (SLDPRT/SLDASM), Parasolid (X_T/X_B), STEP/IGES, PDF. To accelerate project integration, we supply 3D models of a pole, drive and interphase rods to check clashes in the customer’s BIM/CAE environment. On request we perform supervisory installation, author’s support and supply of spare parts kits.

Engaging contractors and manufacturers

We seek partners for serial manufacture, installation and service of disconnectors in the 110–150 kV range. We provide process charts, equipment and tooling lists, quality control plans, preventive and commissioning procedures. We adapt documentation to the machine park and standards of your enterprise, assist with cooperation on key assemblies (contact system, insulators, drives), and support implementation and staff training. Options for deep localization and product-line expansion (future 220–330 kV levels) are available for investors.

Why work with us

- No need to maintain a large team of highly qualified engineering staff - you receive a complete documentation set that can be used by a mid-level engineer.
- No need to build pilot prototypes - our experience allows us to launch serial production successfully.
- Working to our documentation - your specialists will receive guidance on all aspects of manufacturing the RDZ-150 disconnectors.