Typical Solution: Terminal Boxes (Terminal Cabinets) YAZTS, YAZTN, YAZV for 35–220 kV Substations

Published: 11.06.2026 · Author: engineering department of LK Energy LLC

Typical solution for terminal boxes (terminal cabinets) for 35–220 kV substations: YAZTS / YAZ-TT — current transformer terminal boxes, YAZTN / YAZ-TN — voltage transformer terminal boxes, YAZV — circuit breaker terminal box. Five sets of diagrams based on real substation reconstruction projects from 2023–2025: outdoor switchgear (OSG) cabinets — 110 and 220 kV — in stainless steel enclosures, and boxes for 35 kV connections. Diagrams are freely available below, the DWG set is available free of charge on request via the form.

What a terminal box is and why it is used at a substation

The secondary circuits of current and voltage transformers from a substation's outdoor switchgear need to be brought together in one place: routed to terminal blocks, grounded (per the solution's diagrams, using solid 2.5 mm² wire), sealed for revenue metering circuits, and provided with heating and lighting for maintenance. This is exactly the function of a terminal box (terminal cabinet) — a low-voltage outdoor enclosure installed next to the outdoor switchgear equipment. Each enclosure contains: terminal rows with test sockets and disconnecting links, test blocks, auxiliary circuit breakers, a heater with thermostat, a light fixture and a socket outlet. YAZZ is LK Energy's internal designation for this order series.

The family covers the main secondary switching nodes of outdoor switchgear: YAZTS / YAZ-TT — current circuits for metering (class 0.5S, sealable) and protection (10P); YAZTN / YAZ-TN — voltage circuits with metering circuit integrity monitoring; YAZV — circuit breaker drive circuits and disconnector operational interlocking.

Technical parameters of the solution

• Design: outdoor enclosures; for the 110/220 kV substation project — stainless steel, 600 mm width; cable entries — PG cable glands, IP54
• YAZ-TT 35 kV: four CT groups — metering and measurement 0.5S/10VA/5FS (sealable), protection and power supply 10P/20VA/20ALF; WGO 3 current terminals with test sockets, KP5 connection block
• YAZ-TN 35 kV: UTWE 6/4+1 test blocks, iC60N 2A breakers with auxiliary contacts, EL-11 metering circuit monitoring relay, provision for an active ferroresonance suppressor
• YAZTS 110/220 kV: URTK 6 measuring terminals with SB 3-8-T disconnecting links and a protective profile, metering circuit sealing zone
• YAZV-200: automation and signaling circuits (up to 90 UT 4 terminals), disconnector operational interlocking circuits (up to 100 terminals), CLBSV 100 load-break switches
• In each box: 75–100 W heater with thermostat, light fixture, socket outlet; auxiliary circuits — PV-3 1–1.5 mm² wire
• Development years: 2023–2025, diagram language — Ukrainian; ratings for a specific design are agreed via the technical questionnaire

Package contents and downloads

Preview

DWG set on request

We will send the complete DWG set to your email free of charge: YAZ-TT and YAZ-TN 35 kV with CT/VT group connection diagrams, as well as YAZTS, YAZTN and YAZV-200 for 110/220 kV OSG cabinets in stainless steel design.

Frequently Asked Questions

What is the difference between YAZTS, YAZTN and YAZV boxes?

YAZTS (at 35 kV — YAZ-TT) brings together the secondary circuits of current transformers: measuring terminals with disconnecting links and test sockets, a separate sealing zone for metering circuits. YAZTN (YAZ-TN) — voltage transformer circuits: test blocks, monitored breakers, a metering circuit integrity relay. YAZV — circuit breaker drive circuits, automation, signaling and disconnector operational interlocking.

Can this solution be used in my substation's project?

Yes — as a typical baseline solution. The diagrams correspond to real substation reconstruction projects from 2023–2025: 110/220 kV OSG cabinets in stainless steel design and 35 kV connections. Site-specific adaptation, the cable schedule, and compliance with the applicable PUE (Electrical Installation Rules) / DSTU (Ukrainian national standards) are the responsibility of the design engineer.

How do I get the DWG files?

Fill out the form on this page — we will send the set to your email within one business day.

Does LK Energy manufacture these boxes?

Yes. Terminal boxes are 0.4 kV NKU (low-voltage switchgear and controlgear assembly) manufactured in-house in Odesa, including in stainless steel enclosures for outdoor installation at outdoor switchgear. See also the equipment catalog.

Can you help select the configuration for my site?

Yes, we advise design engineers: box composition for a specific switchgear layout, CT/VT accuracy classes, filling out technical questionnaires — +38 067 104 94 91. See also: typical solution for 10 kV KRUN switchgear, 10 kV distribution point on KSO cells.

The diagrams are provided as a reference typical solution. Site-specific adaptation, protection relay setting calculations, and compliance with applicable standards (PUE, DSTU, DBN — state building codes) are the responsibility of the design engineer. LK Energy is not liable for application of the solution without adaptation to the conditions of a specific site.