Короткий ответ: Treat a 220 kV underground cable specification as a system interface schedule, not as a cable datasheet. Before manufacture, connect the electrical duty, route zones, секции оболочки, аксессуары, factory lengths, and acceptance evidence. An open interface can still produce wrong lengths, incompatible accessories, an unbalanced bonding layout, or evidence that does not cover the supplied system.
МЭК 62067:2022 is the controlling international product-and-test basis for extruded single-core cable systems above 150 кВ и до 500 kV rated voltage under usual fixed-installation conditions. It does not provide one universal 220 kV construction, пропускная способность, sheath arrangement, длина барабана, or route design. Those decisions come from the project interfaces.
The specification must define a system, not a voltage label
“220 kV XLPE cable to IEC 62067” is a starting point, not a complete specification. The common designation 127/220(245) kV records voltage to earth, rated system voltage, and maximum system voltage. It still says nothing about continuous load, fault duty, материал проводника, route losses, water barrier, sheath fault current, метод склеивания, аксессуары, installation force, or evidence boundaries.
МЭК 60183 treats high-voltage selection as a coordinated decision involving conductor size, insulation level, строительство, аксессуары, special screen bonding, и условия окружающей среды. МЭК 60287 then provides steady-state rating and loss equations while deliberately leaving important construction, среда, and agreed service-margin inputs to the actual project. This is why a catalogue ampacity cannot close a 220 kV route design.
| Interface to freeze | Minimum controlled inputs | What can fail if it remains open |
|---|---|---|
| Electrical design basis. | U0/U(Один), частота, заземление, continuous and cyclic load, emergency duty, fault current and duration, impulse and switching duty. | Wrong insulation basis, проводник зоны, metallic sheath duty, or accessory class. |
| Route and thermal model. | Installation zones, soil/backfill data, каналы, tunnel air, глубина, расстояние, формирование, переправы, adjacent heat sources. | Unverified current rating or a local thermal bottleneck. |
| Кабельная конструкция. | Дирижер, XLPE system, блокировка воды, металлическая оболочка, внешняя оболочка, fire or environmental declarations. | Construction that does not match route, fault, вода, or interface conditions. |
| Sheath system. | Bonding schematic, длины секций, earthing, поля ссылок, bonding leads, SVLs, standing and transient voltage study. | Circulating losses, unsafe sheath voltage, or inadequate insulation coordination. |
| Accessories. | Joint type, termination type, connected equipment, размеры, materials, field control, mechanical and sealing interfaces. | A nominally matched accessory outside the qualified system family. |
| Lengths and logistics. | Route chainage, суставные отсеки, направление вытягивания, drum limits, transport envelope, storage and handling plan. | Extra joints, inaccessible bays, unsuitable drums, or impossible pulls. |
| Evidence and acceptance. | Standard edition, prequalification and type-test envelope, routine/sample tests, ITP, site records, after-laying test. | Reports that do not cover the delivered design or installed circuit. |
Route data should enter as controlled zones
A long underground circuit rarely has one thermal environment. Прямое захоронение, concrete-encased ducts, horizontal directional drilling, bridge approaches, туннели, суставные отсеки, substation entries, and congested crossings create distinct zones. Each zone needs chainage, geometry, thermal assumptions, метод установки, and design status. The governing rating may come from a short restrictive segment rather than the average route.
The separate XWA guide to underground route constraints explains thermal, тянет, and civil effects in detail. For a 220 kV specification, summarize those calculations in a route-interface register. Record zone boundaries, approved inputs, the responsible discipline, the calculation revision, and any sensitivity that still affects conductor or construction selection.
Three values deserve explicit source records: soil or backfill thermal resistivity, ambient or soil temperature, and cable arrangement. A generic value copied from a tender table is not equivalent to route evidence. Where drying, seasonal change, or uncertain duct occupancy is credible, the rating study should explain the treatment. Do not bury that uncertainty inside one ampacity number.
Sheath design creates its own section schedule
В 220 кВ, the metallic sheath is part of the electrical and thermal system. It provides screening, carries specified fault duty, and interacts with water protection and accessories. Its bonding arrangement influences standing sheath voltage, циркулирующий ток, потери, current rating, overvoltage protection, and safe work conditions.
Single-point bonding, solid bonding, and cross-bonding are engineering options, not quality grades. СИГРЭ ТБ 797 emphasizes that AC transmission systems at and above 66 kV require a project-specific sheath bonding design based on the cable, аксессуары, installation conditions, and connected system. Cross-bonding is common on longer 220 kV routes because balanced minor sections can reduce net induced voltage and circulating loss, but it is not an automatic rule.
| Bonding decision | Data that must be coordinated | Required record |
|---|---|---|
| Major and minor section lengths. | Route chainage, phase arrangement, joint-bay positions, геометрия кабеля. | Section schedule with actual and calculated lengths. |
| Link boxes and bonding leads. | Location, accessibility, conductor duty, insulation level, earth connection. | Equipment schedule and termination drawing. |
| Sheath voltage limiters. | Power-frequency standing voltage, transient study, energy duty, insulation coordination. | Study assumptions and selected rating basis. |
| Metallic sheath size. | Fault current, duration, return paths, bonding mode, material and temperature limits. | Fault-duty calculation linked to construction drawing. |
| Commissioning test points. | Section isolation, links, earths, oversheath access, monitoring interfaces. | Test schematic matching as-built connections. |
A late change to a joint bay therefore changes more than civil chainage. It may disturb minor-section balance, cable delivery lengths, расположение окна ссылок, bonding-lead length, pulling sections, and the test plan. Return the change through the interface register before releasing drum manufacture.
Manufacturing lengths are an engineering output
Derive factory delivery length from route chainage and installation analysis, not only from maximum drum capacity. A useful length schedule aligns four layers: accessible joint-bay positions, feasible pulls, balanced bonding sections, and transportable drums. It also includes termination allowances, joint preparation allowances, route tolerances, sample requirements, and the approved policy for spare length.
Unnecessary joints add accessory interfaces and installation work. Excessively long sections can exceed drum mass, transport envelope, напряжение, давление на боковую стенку, or site handling capability. The optimum schedule is therefore not “fewest joints” in isolation. It is the lowest-risk arrangement that satisfies electrical, гражданский, установка, логистика, and maintenance constraints together.
The manufacturing release should identify each phase and drum, start and end chainage, направление вытягивания, destination joint or termination, calculated section length, ordered length, drum dimensions and mass, and corresponding bonding section. Drum marks and packing documents should use the same identifiers as drawings and site records.
Accessories must belong to the offered system family
Do not accept a 220 kV joint or termination only because its nameplate voltage matches the cable. The cable insulation diameter, screen geometry, conductor connection, material interfaces, and electric-field control all matter. Thermal expansion, уплотнение, mechanical loads, and connected equipment also affect the interface.
СИГРЭ ТБ 968 describes cable-accessory interfaces as critical electrical, термический, material, and thermomechanical boundaries. Surface preparation, interface pressure, смазка, contamination control, and material compatibility can affect performance. The accessory data sheet should therefore reference the exact cable construction and dimensional tolerance range, not a generic 220 kV family label.
Termination interfaces also need the connected equipment basis: outdoor air termination, GIS interface, or transformer connection; pollution and altitude conditions; mechanical loading; phase spacing; support arrangement; fluid or gas boundary where applicable; and terminal hardware. Joint bays need working space, environmental control, earthing, support, and a controlled installation procedure.
Map IEC 62067 evidence to the supplied design
МЭК 62067:2022 specifies requirements and tests for the cable system, кабели, and accessories in its scope. Review each evidence layer by purpose. A prequalification report addresses long-term thermo-electrical behavior for a defined system family. Type-test evidence addresses a defined design. Routine and sample tests address manufactured output. Site records and after-installation tests address the assembled circuit. One document cannot replace all other layers.
| Evidence layer | Question answered | Interface check |
|---|---|---|
| Prequalification. | Has the system family completed the required long-duration qualification? | Compare conductor, система изоляции, аксессуары, размеры, materials, класс напряжения, and permitted extensions. |
| Типовые испытания. | Has the defined cable-and-accessory design passed the applicable design tests? | Confirm offered joint and termination combinations are represented. |
| Routine tests. | Has each required manufactured length or accessory passed production checks? | Trace reports to drum, phase, accessory serial identity, and drawing revision. |
| Sample tests. | Do selected production characteristics meet specified requirements? | Define sampling frequency, witness points, acceptance, and nonconformance handling. |
| Installation records. | Was transport, тянет, preparation, jointing, and termination work controlled? | Link personnel, среда, measurements, materials, photographs, and check sheets. |
| After-installation tests. | Does the assembled circuit meet the approved commissioning basis? | Match source capability, длина маршрута, аксессуары, test connections, method, and acceptance criteria. |
СИГРЭ ТБ 841 reviews modern after-laying test sources and their limitations for HV and EHV systems. Agree the method, Напряжение, duration, source frequency, diagnostic additions, and test connections in the project test schedule. Do not improvise them after assembling the circuit.
Seven hold points prevent expensive late changes
- Design-basis hold: freeze U0/U(Один), заземление, load cases, fault duty, insulation coordination, and governing editions.
- Route-model hold: approve chainage, zone inputs, rating model, installation calculations, and unresolved sensitivities.
- System-design hold: approve cable construction, дирижер, размеры, металлическая оболочка, water barrier, and environmental declarations.
- Accessory-interface hold: approve joints, прекращение, dimensional envelopes, connected equipment, and qualification mapping.
- Bonding hold: approve section schedule, поля ссылок, earthing, SVLs, insulation coordination, and test access.
- Length-and-drum hold: approve delivery lengths, направление вытягивания, суставные отсеки, drum details, route tolerances, and identifiers.
- Quality-plan hold: approve the ITP, report templates, прослеживаемость, witness points, nonconformance process, and commissioning method.
These hold points should use controlled revisions and named owners. CIGRE’s 2026 lifecycle QA/QC work identifies interface management as a central risk because deficiencies in early project phases can propagate into manufacturing, transport, установка, и эксплуатация. A signed datasheet without closed interfaces is therefore not a reliable manufacturing release.
A practical 220 kV interface register
The register can remain compact if every line has five fields: requirement, verified input, evidence reference, responsible owner, and status. Open items should show the decision date and the downstream documents they block. The most useful register is not the longest one; it is the one that makes dependencies visible.
- Voltage and system: 127/220(245) kV designation, AC frequency, заземление, overvoltage basis, load and fault cases.
- Маршрут: chainage, zone drawings, thermal values, формирование, расстояние, глубина, civil method, pull and bending checks.
- Строительство: дирижер, система изоляции, металлическая оболочка, water protection, внешняя оболочка, dimensions and tolerances.
- Accessories: exact joint and termination designs, cable dimensional windows, connected equipment, installation conditions.
- Bonding: major/minor sections, поля ссылок, leads, earths, SVLs, sheath-voltage and fault-duty calculations.
- Производство: phase/drum schedule, ordered lengths, samples, маркировка, inspection points, transport and storage limits.
- Evidence: qualification matrix, production reports, traceability dossier, installation records, as-builts, commissioning report.
Common questions about 220 kV underground specifications
Does IEC 62067 define the current rating of a 220 кВ кабель?
Нет. МЭК 62067 defines tests and requirements within its scope. Current rating depends on the actual construction, потери, installation geometry, thermal environment, bonding arrangement, and operating duty. МЭК 60287 provides calculation methods, not one universal catalogue value.
Is cross-bonding mandatory for every 220 kV route?
Нет. Engineers must design the sheath system for the circuit. Cross-bonding often suits longer routes. Single-point or solid arrangements may fit particular section lengths and conditions. The decision requires induced-voltage, потеря, fault, transient, earthing, and maintenance analysis.
Can joint-bay positions remain open until after cable manufacture?
That creates major risk. Joint bays control delivery lengths, pulling sections, bonding-section balance, link-box locations, accessory quantities, and site access. Provisional positions should block final drum release unless an approved tolerance and change method exist.
Does a prequalification report prove the delivered circuit?
It supports a defined qualified system family. Map the offered construction and accessories to that family and its extension rules. Production, установка, and commissioning evidence remain separately necessary.
What belongs in the final technical submission?
The submission should align the cable schedule, construction drawings, дополнительные интерфейсы, bonding study, rating report, delivery-length schedule, qualification matrix, ITP, production reports, installation records, as-built drawings, and after-installation test report under one revision-controlled index.
Инженерное заключение
A reliable 220 kV underground cable specification is an interface-control document. МЭК 62067 establishes the system test basis. Project performance also depends on links between electrical duty, route zones, строительство, металлическая оболочка, аксессуары, lengths, установка, and evidence. Release manufacture only when every drum and accessory has a traceable path from design input to route position. The same path should connect the qualification envelope to the commissioning record.
The relevant XWA 127/220(245) kV product range provides voltage-class and construction context, while the broader high-voltage cable portfolio places it within the 66-500 kV system range. For neutral engineering guidance on project-specific sheath design, see the CIGRE technical overview.
Submit the 220 kV Interface Schedule
For an engineering review, provide U0/U(Один), frequency and grounding, continuous and emergency load cases, fault current and duration, route chainage and thermal zones, formation and civil method, bonding concept, joint-bay and termination interfaces, required IEC edition, qualification and test requirements, delivery quantities, и пункт назначения. XWA Мощность & Cable can align the proposed construction, accessory interface data, manufacturing lengths, and evidence schedule with the approved system basis. Final capability confirmation follows closure of the technical interfaces.