IEC + CEA / CBIP and ANSI / IEEE compared
The IEC + CEA / CBIP set and the ANSI / IEEE set design pooling and switching substations with the same design steps. They differ in the standards each step follows, in the voltage levels and the frequency, and in the words and units of the deliverables. The method of the earth mat and of the HV yard's lightning protection is common to both.
Read first: The IEC + CEA / CBIP set · The ANSI / IEEE set
1Levels and frequency
the table compares the scope of the sets. A project takes the levels of its own set.
| Item | IEC + CEA / CBIP set | ANSI / IEEE set |
|---|---|---|
| Pooling substations, HV | 33 kV, 66 kV, 132 kV, 220 kV, 400 kV | 69 kV, 115 kV, 138 kV, 161 kV, 230 kV, 345 kV |
| Switching substations | Up to 765/400 kV | Up to 345/230 kV |
| Collector (MV) bus | 33 kV, or 11 kV at 66 kV and 132 kV | 34.5 kV |
| System frequency | 50 Hz or 60 Hz | 60 Hz |
| Generating plants with synchronous generators | Designed | Not offered |
| Insulation levels | Um and BIL per CEA Construction Regulations 2022 Reg. 45(1), Table 9 | Rated maximum voltage and BIL per IEEE C37.04-2018 Table 6 |
| Switching impulse level | SIWL at 400 kV and 765 kV | BSL at 345 kV |
| Design fault level | The minimum short-time withstand per CEA Construction Regulations 2022 Reg. 43(1), Table 6 | A rated short-circuit current of IEEE C37.04-2018 Tables 12 and 16 |
2Short circuit
Both sets study the same network: the grid behind its lines, the transformers, the MV sections with their neutral earthing resistors and the plant's converter infeed. The methods differ in the source voltage, the corrections, the treatment of the DC component and the ratings checked. the table compares them.
| Item | IEC + CEA / CBIP set | ANSI / IEEE set |
|---|---|---|
| Standard | IEC 60909-0:2016 | IEEE C37.010-2016 with IEEE C37.04-2018 |
| Source voltage | The equivalent voltage source with the voltage factor c | E, taken at the level's system maximum voltage (C37.010 §5.1.2) |
| Corrections | The voltage factor c and the transformer correction KT | None: the grid from its fault levels, the transformers at their rated impedance |
| Faults | Three-phase, phase-to-earth, phase-to-phase and two-phase-to-earth | Three-phase and line-to-ground |
| DC component | The peak current ip by the factor κ | A duty factor above the rated DC time constant of 45 ms (C37.010 §5.1.4, §5.2.2) |
| Breaking or interrupting check | IEC 62271-100:2008: the breaking current against I″k | The interrupting duty against the rated short-circuit current (C37.010 §5.2.3) |
| Making or closing check | Rated making current, 2.5 × breaking at 50 Hz and 2.6 × at 60 Hz, against the peak ip (IEC 62271-100:2008 §4.103) | Closing and latching 2.6 × the rated short-circuit current at 60 Hz (C37.04 §5.6.2.3) |
| Short-time check | The thermal current against the rated short-time current | The current against the rated short-circuit current for 2 s below 100 kV, 1 s at 100 kV and above |
The IEC method takes the equivalent voltage source c Un/√3 at the fault location, with c 1.10 for the maximum currents and 1.00 for the minimum. The C37.010 method takes the highest typical operating voltage at the breaker, which the design reads as the level's system maximum voltage. The C37.010 duty factor grows with the X/R ratio above the breaker's rated DC time constant. The IEC method carries the DC component in the peak current ip.
3Clearances and the fence
The IEC + CEA / CBIP set takes its clearances from the level table of the CEA / CBIP practice. The ANSI / IEEE set takes them from the row of RUS Bulletin 1724E-300 Table 4-7 for the level's BIL, with the NESC rules in place of the sectional clearance. the table compares the checks.
| Item | IEC + CEA / CBIP set | ANSI / IEEE set |
|---|---|---|
| Phase-to-earth or phase-to-ground | The level table; CEA Safety Regulations 2023 Reg. 46(2)(i) | To grounded parts, RUS Bulletin 1724E-300 Table 4-7 |
| Phase-to-phase | The level table; CEA Safety Regulations 2023 Reg. 46(2)(i) | Metal to metal and the switch spacing, RUS Bulletin 1724E-300 |
| Sectional clearance | The level table; CEA Safety Regulations 2023 Reg. 46(2)(iii), Schedule V | None: NESC Rule 124A1, Table 124-1, by BIL |
| Ground clearance | The level table; CEA Safety Regulations 2023 Reg. 46(2)(iii), Schedule V | The conductor above grade, RUS Bulletin 1724E-300 Table 4-7 |
| Bottom of insulators | At least 2.5 m (CEA) | 2.6 m above grade (NESC Rule 124A) |
| Above 1000 m | The clearances corrected by the altitude factor of IEC 60071-2 | The clearances of a higher standard BIL, by the RUS bulletin |
| Fence | Not less than 1.8 m, earthed (CEA Safety Regulations 2023 Reg. 51(ii)(a)) | At least 2.13 m (NESC Rule 110A1), with the safety clearance zone of Rule 110A2 |
The IEC + CEA / CBIP set also checks the yard's clearances against the minimum clearances of IEC 61936-1:2021. The ANSI / IEEE set's yard geometry is derived from its clearances, so a level's bay width and heights follow its RUS row.
4Earthing and grounding
Both sets design the earth mat by IEEE Std 80-2013: the tolerable touch and step voltages, the grid current, the grid resistance, and the mesh and step voltages (Mesh voltage and touch voltage, Step voltage). The materials, the body weight and the spacing search differ. the table compares them.
| Item | IEC + CEA / CBIP set | ANSI / IEEE set |
|---|---|---|
| Name | Earth mat | Ground grid |
| Conductor | Mild steel rod, the steel 1020 constants of IEEE Std 80-2013 Table 1 | Annealed soft-drawn copper, RUS Bulletin 1724E-300 Table 9-2 |
| Temperature limit | 500 °C, the design's limit for welded steel joints | 1083 °C, the fusing temperature of annealed copper |
| Corrosion allowance | 0.12 mm a year per surface over 25 years | None |
| Sizes | The standard rod diameters 16, 20, 25, 32, 40 and 50 mm | 4/0 AWG to 1000 kcmil |
| Body weight of the verdict | 50 kg | 70 kg |
| Mesh spacing search | From 10 m in steps of 0.5 m to 3 m | From 12.19 m in steps of 0.61 m to 3.05 m |
| Grid resistance | Reported against 1 Ω, a limit the checklist credits to CBIP Publication 311, with the IS 3043 cross-check | Not compared with a limit |
The lighter body weight of the IEC + CEA / CBIP set gives the lower tolerable voltages, so the same mat has less margin there (Tolerable body current). The steel mat carries a corrosion allowance on its sized diameter, and the copper grid none (Conductor sizing).
5Lightning protection
The sets protect the yard in the same way. The HV yard takes the rolling sphere of IEEE Std 998-2012, with the striking distance of Mousa from each protected level's BIL. The MV areas and the building take the lightning protection level (LPL) I sphere of IEC 62305-3. The IEC + CEA / CBIP set adds the shielding requirement of CEA Construction Regulations 2022 Reg. 44(2)(c) to its checklist, and the ANSI / IEEE set lists NFPA 780 for the building.
6Bus schemes, designations and instrument transformers
the table compares the single-line diagram of the sets. The double main bus, one-and-a-half breaker, single sectionalised bus and single bus are common to both (Bus schemes). The ring bus is offered by the ANSI / IEEE set only.
| Item | IEC + CEA / CBIP set | ANSI / IEEE set |
|---|---|---|
| Default bus scheme | Single sectionalised bus at 33 kV and 66 kV, double main bus at 132 kV and 220 kV, one-and-a-half breaker at 400 kV and 765 kV | Ring bus at 69 kV to 161 kV and one-and-a-half breaker at 230 kV and 345 kV |
| Norm named on the SLD | CEA / CBIP, CEA Construction Regulations 2022 Reg. 44(2)(a), Table 7 | ANSI / IEEE |
| Device designations | IEC 81346-2:2019 letter codes: −Q0 breaker, −Q1 and −Q2 bus isolators, −Q9 line isolator, −Q8 earth switch | IEEE C37.2-1996 device numbers: 52 circuit breaker, 89 disconnect switch |
| CT secondary | 1 A | 5 A, multi-ratio HV CTs |
| CT cores | 0.2S metering, 5P20 and PS protection | 0.15 class metering, C800 relaying |
| Voltage transformer secondary | 110/√3 V | 115/√3 V |
| Reactive power device | Static var generator (SVG), ± 25 % of the plant's MW | STATCOM, power factor 0.95 at the high side |
7Station service, units and terms
the table compares the auxiliary supply and the deliverables. The design steps are the same in both sets.
| Item | IEC + CEA / CBIP set | ANSI / IEEE set |
|---|---|---|
| AC supply | 415 V | 480Y/277 V |
| DC supply | 220 V, VRLA batteries | 125 V, vented lead-calcium cells at the 8 h rate |
| Standby source | DG set with an AMF panel | Standby generator with an automatic transfer switch |
| Low-voltage breakers | IEC 60947-2 frames | IEEE C37.13-2015 frames |
| Units | SI | Inch-pound: feet, inches, miles, °F, AWG and kcmil |
| Sheets | A1 sheets, DXF in millimetres | ANSI D (34 × 22 in) at engineering scales, DXF in inches |
| Terms | Earthing, earth mat, isolator, lightning arrester, CVT, auxiliary supply | Grounding, ground grid, disconnect switch, surge arrester, CCVT, station service |
Both sets keep masses in tonnes and soil resistivity in Ω·m. The tags on the drawings, such as ICT-1 and LA, are the same in both sets.
8Compliance checklists
The checklists of the IEC + CEA / CBIP set are CEA / Indian, IEC and IEEE. Those of the ANSI / IEEE set are NESC and NFPA, IEEE and ANSI, and Interconnection. The IEEE 80 and IEEE 998 items use the same checks in both sets, with the 70 kg body weight in the ANSI / IEEE set. The statuses, the answers and the exports are the same in both sets (The IEC + CEA / CBIP set, Compliance checklists).
[1]CEA Construction Regulations 2022, Central Electricity Authority (Technical Standards for Construction of Electrical Plants and Electric Lines) Regulations, 2022.
[2]CEA Safety Regulations 2023, Central Electricity Authority (Measures relating to Safety and Electric Supply) Regulations, 2023.
[3]IEEE Std 80-2013, IEEE Guide for Safety in AC Substation Grounding.
[4]IEEE C37.010-2016, IEEE Application Guide for AC High-Voltage Circuit Breakers.
[5]IEEE C37.04-2018, IEEE Standard for Ratings and Requirements for AC High-Voltage Circuit Breakers.
[6]IEEE C37.2-1996, Standard Electrical Power System Device Function Numbers.
[7]ANSI C2-2007, National Electrical Safety Code.
[8]RUS Bulletin 1724E-300, Design Guide for Rural Substations.
[9]IEC 60909-0:2016, Short-circuit currents in three-phase AC systems, Part 0: Calculation of currents.
[10]IEC 62271-100:2008, High-voltage switchgear and controlgear.
[11]IEC 60071-1:2019, Insulation co-ordination.
[12]IEC 61936-1:2021, Power installations exceeding 1 kV AC.
[13]IEEE Std 998-2012, IEEE Guide for Direct Lightning Stroke Shielding of Substations.
[14]IEC 62305-3, Protection against lightning.
[15]CBIP Publication 311, Manual on Earthing of AC Power Systems.
[16]IEC 81346-2:2019, Classification of objects and codes for classes.