Box substation commissioning norm work-content boundaries and AC withstand-test charging under railway TB/T 10829-2024 Vol. 8 (power works)

Topic Positioning

The composition and work-content boundaries of the "box substation commissioning" items in railway electrical system commissioning, and how AC withstand tests are charged in estimates. Per TB/T 10829-2024 Vol. 8 Chapter 15 and the supporting acceptance/testing standards.

Core Conclusions

1. Item composition (Chapter 15 Section 2, all "per unit"):

• Box substation commissioning: DY-1407 (<= 1x630kVA), DY-1408 (<= 2x630kVA), DY-1409 (<= 1x1250kVA), DY-1410 (<= 2x1250kVA);
• Box reactor commissioning: DY-1411 (<= 100kvar);
• Box distribution-station commissioning: DY-1412 (1-in-4-out), DY-1413 (2-in-4-out);
• Indoor substation commissioning: DY-1414~DY-1417 (<= 1x630 / 2x630 / 1x1250 / 2x1250kVA). Base prices and consumptions per the norm tables.

2. Work-content boundary: the verbatim content is "high- and low-voltage insulation testing; functional and grounding-continuity testing" — insulation and functional/grounding-continuity only. AC withstand testing is not in the item.

3. AC withstand charging:

1. It is a handover test: TB 10420-2018, 5.16.3: "Box substations and box reactors shall undergo handover tests; main electrical performance checks per GB 50150. Inspection: contractor tests all, supervisor witnesses; method: tested by a qualified testing body with supervision witnessing." TB 10757-2018, 5.16.3 the same.
2. TB/T 10438-2024 Annex A sets AC withstand voltages for transformers, reactors, and other primary equipment (Table A.0.1 by oil-immersed/dry type) — a statutory test.
3. Conclusion: the volume sets no standalone "AC withstand test" item; its cost must not be presumed inside "box substation commissioning"; charge it per the handover/inspection fee caliber per actual conditions, and do not re-charge under other commissioning items.

4. Companion items and factors (same chapter; avoid overlap with box commissioning): surge-arrester commissioning DY-1424 (10kV), DY-1425 (35kV) per "group" — "every 3 phases count as 1 group; even with only one or two arrester phases, count 1 group"; earthing-resistance commissioning DY-1426 and 10kV bus commissioning DY-1427 per "group". Box substation installation (DY-1074~DY-1084; work "unpacking/inspection, fixing, wiring, earthing") is separate from commissioning. Factors: 35kV substation items assume one main transformer — each additional adds 0.8; 10kV stations assume one incoming feeder — each additional adds 0.8; transformer items assume oil-immersed — dry types x 0.8.

5. Building reference (not a railway basis): GB 50303-2015, 4.1.6 — box substations assembled from HV switchgear, LV switchgear, and a transformer: the HV portion shall pass handover tests; where HV switches, fuses, and the transformer share one sealed oil tank, tests per product documents; LV panels and feeders: phase-to-phase and phase-to-earth insulation >= 0.5 MΩ; where product standards are silent, AC power-frequency withstand 1000V for 1min; with insulation > 10 MΩ, a 2500V megger is preferred.

Applicable Boundaries

• Applies to railway (incl. high-speed) power works estimates and reviews — box substation/reactor commissioning item selection and AC withstand (handover) test charging; basis TB/T 10829-2024 Vol. 8 (2024); prices per the tables and period adjustments.
• "AC withstand not included" follows the item work-content vs acceptance-standard comparison; projects also follow design, contract, and the employer's inspection-fee rules.
• Box distribution-station, indoor-substation, and box-substation commissioning target different objects — mixing them is misapplication.
• Building box-substation handover tests follow GB 50303-2015 — not interchangeable with railway calibers.

Further Reading

• TB/T 10829-2024 Vol. 8: Chapter 15 commissioning, Section 2 items DY-1407~DY-1417, Section 7 DY-1424~DY-1427; Chapter 9 Section 2 installation DY-1074~DY-1084.
• TB 10420-2018, 5.16; TB 10757-2018, 5.16.
• TB/T 10438-2024 Annex A (AC withstand voltages).
• GB 50150; GB 50303-2015, 4.1.6.