power & environmental monitoring, metering, alarms (POA — not included in estimate)
1
Rack PDU (end-of-row / column head cabinet)
rack PDU
per-rack power distribution + branch metering (POA — not included in estimate)
13
📐 Single-line diagram
⚙️ Electrical schematic (protection & metering)
⛳ Grounding grid layout
🔌 Cable schedule & routing
🗄 Switchgear arrangement
🛡 Protection configuration
📋 Protection settings
Circuit
Protection
Setting
Time
Standard
HV incoming 10 kV
50 instantaneous
739 A
inst
IEC 60255-151 / IEEE 242
HV incoming 10 kV
51 overcurrent
111 A
0.5 s
IEC 60255-151 / IEEE 242
HV incoming 10 kV
51N earth-fault
18 A
0.5 s
IEC 60364-4-41
Transformer 1600 kVA
87 differential
18 A
inst
IEEE C37.91 / GB/T 14285
Transformer 1600 kVA
49 thermal overload
99% of rated
alarm/trip
IEC 60076-7 / IEEE C57.91
LV incoming 0.4 kV
50 instantaneous
18475 A
inst
IEC 60947-2
LV incoming 0.4 kV
51 overcurrent
2771 A
0.3 s
IEC 60947-2 / IEC 60255
LV incoming 0.4 kV
51N earth-fault
462 A
0.3 s
IEC 60364-4-41
LV bus-tie
50/51 overcurrent
2771 A
0.3 s
IEC 60947-2
IT feeder 1
50/51/51N (MCCB)
Ir 351 A - Im 2552 A - Ig 64 A
0.1 s (grading)
IEC 60947-2 / IEC 60255
IT feeder 2
50/51/51N (MCCB)
Ir 351 A - Im 2552 A - Ig 64 A
0.1 s (grading)
IEC 60947-2 / IEC 60255
IT feeder 3
50/51/51N (MCCB)
Ir 351 A - Im 2552 A - Ig 64 A
0.1 s (grading)
IEC 60947-2 / IEC 60255
IT feeder 4
50/51/51N (MCCB)
Ir 351 A - Im 2552 A - Ig 64 A
0.1 s (grading)
IEC 60947-2 / IEC 60255
IT feeder 5
50/51/51N (MCCB)
Ir 351 A - Im 2552 A - Ig 64 A
0.1 s (grading)
IEC 60947-2 / IEC 60255
IT feeder 6
50/51/51N (MCCB)
Ir 351 A - Im 2552 A - Ig 64 A
0.1 s (grading)
IEC 60947-2 / IEC 60255
+2 more feeders
50/51/51N (MCCB)
per feeder load
0.1 s (grading)
IEC 60947-2
Settings are illustrative starting points — confirm with a protection coordination study per IEC 60255 / IEEE 242.
📚 Calculation book
CALCULATION BOOK
1600 kVA - 10kV/0.4kV - N+1 - illustrative
1. Load calculation
Standard: IEC 60076 - IEC 60364-5-52
Parameter
Formula
Value
Connected load
P = sum(kW)
1,680 kW
Demand factor
Kd
0.9
Demand power
Pd = P x Kd
1,512 kW
Power factor
cos(phi) before -> after
0.95 -> 0.95
Design apparent power
Sd = Pd / cos(phi)
1,592 kVA
Transformer loading
Sd / Srated
99%
2. Short-circuit calculation
Standard: IEC 60909
Parameter
Formula
Value
System impedance (pu)
Zs = S / Ssc
0.32% (on 1600 kVA base)
Transformer impedance
Zt = Z%
6%
Total impedance
Z = Zt + Zs
6.32%
LV prospective Isc
Isc = In / Z
36.5 kA
HV prospective Isc
Isc = Ssc / (sqrt(3) x V)
28.9 kA
Breaking check
Icu >= Isc
LV 50 kA (1.4x margin) PASS
3. Voltage drop
Standard: IEC 60364-5-52 Annex G
Parameter
Formula
Value
Main feeder
dU = sqrt(3) x I x L x R / V
300 mm2 - dU 0.90% @ 60 m
Limit
max 3%
within limit
Transformer volt. reg.
dU ~ loading x Z% x sin(phi)
1.9% at full load
4. Reactive power / harmonics
Standard: IEC 61921 (PFC) - IEEE 519 (harmonics)
Parameter
Formula
Value
Required compensation
Qc = Pd x (tan1 - tan2)
0 kvar
PFC bank
standard step
0 kvar
Detuned reactor
p = 6%
n/a
5. Grounding
Standard: IEC 60364-5-54 earthing arrangements and protective conductors LV earthing target 10 ohm (TN systems); 4 ohm used as a conservative design target - target 4 ohm
Parameter
Formula
Value
Single rod resistance
R1 = rho/(2 x pi x L) x ln(4L/d)
39.6 ohm
Rods required
n = R1 / (target x 0.8)
13 rod(s) <= 4 ohm
Rod spec
dia x length
20 mm x 2.5 m
This calculation book is illustrative it consolidates the computed values with the referenced standards. A licensed engineer must verify and seal final design documents for construction.
🔧 Secondary schematic (control & signal)
🔩 Terminal strip (typical)
🔋 UPS system
Parameter
Value
UPS module capacity
1250 kVA (1125 kW @ 0.9 PF)
Redundancy topology
2N → 2 module(s) across 2 path(s)
UPS efficiency basis
92% (online double-conversion)
Battery autonomy
10 min → ≈ 181 kWh
🌡️ PUE & efficiency
Parameter
Value
PUE (computed)
1.68 = total facility load ÷ IT load
Rack density
8 kW/rack → 125 racks
Reference range
1.2–1.6 typical; GB 50174 / Uptime Institute recommend monitoring and minimizing
Cable & grounding pricing:Cable conductors and grounding are priced from the confirmed cables-trays-grounding price reference (per-metre copper YJV; aluminium remains POA). The main copper busbar is POA — its length is project-specific.
Busway (high-current feeders):For LV feeders above ~2500 A, a busway (母线槽) trunking system is recommended instead of parallel cables.
PUE estimate:Computed PUE 1.68 (typical modern data centers 1.2–1.6; actual depends on cooling technology and climate).
UPS pricing:Data-center UPS modules are quoted per project — the online catalogue covers 1–3 kVA units, so these are shown POA.
UPS battery bank:A 181 kWh battery bank provides 10 min autonomy at full IT load — sized separately and quoted per project.
DCIM & rack PDU:DCIM monitoring and per-rack PDUs (列头柜/rack PDU) provide power metering and branch monitoring — quoted per project.
Tier & redundancy:Uptime Tier III requires N+1 minimum redundancy; you selected 2N. 2N → two independent power paths, each sized for 100% of the IT load (fault-tolerant).
UPS battery autonomy:10 min runtime at full IT load ≈ 181 kWh battery (sized separately, quoted per project).
Rack density:8 kW/rack → 125 racks. Within typical air-cooled range.
PUE warning:Computed PUE 1.68 exceeds the typical modern range (1.2–1.6) — consider more efficient cooling (liquid / close-coupled / free cooling) to cut energy cost.
Example 2 — 400 kW Data Center (N+1) · FOB $224,637
Data center power system · N+1 · 10kV/0.4kV · Tier II
power & environmental monitoring, metering, alarms (POA — not included in estimate)
1
Rack PDU (end-of-row / column head cabinet)
rack PDU
per-rack power distribution + branch metering (POA — not included in estimate)
7
📐 Single-line diagram
⚙️ Electrical schematic (protection & metering)
⛳ Grounding grid layout
🔌 Cable schedule & routing
🗄 Switchgear arrangement
🛡 Protection configuration
📋 Protection settings
Circuit
Protection
Setting
Time
Standard
HV incoming 10 kV
50 instantaneous
291 A
inst
IEC 60255-151 / IEEE 242
HV incoming 10 kV
51 overcurrent
44 A
0.5 s
IEC 60255-151 / IEEE 242
HV incoming 10 kV
51N earth-fault
7 A
0.5 s
IEC 60364-4-41
Transformer 630 kVA
87 differential
7 A
inst
IEEE C37.91 / GB/T 14285
Transformer 630 kVA
49 thermal overload
95% of rated
alarm/trip
IEC 60076-7 / IEEE C57.91
LV incoming 0.4 kV
50 instantaneous
7275 A
inst
IEC 60947-2
LV incoming 0.4 kV
51 overcurrent
1091 A
0.3 s
IEC 60947-2 / IEC 60255
LV incoming 0.4 kV
51N earth-fault
182 A
0.3 s
IEC 60364-4-41
LV bus-tie
50/51 overcurrent
1091 A
0.3 s
IEC 60947-2
IT feeder 1
50/51/51N (MCCB)
Ir 132 A - Im 960 A - Ig 24 A
0.1 s (grading)
IEC 60947-2 / IEC 60255
IT feeder 2
50/51/51N (MCCB)
Ir 132 A - Im 960 A - Ig 24 A
0.1 s (grading)
IEC 60947-2 / IEC 60255
IT feeder 3
50/51/51N (MCCB)
Ir 132 A - Im 960 A - Ig 24 A
0.1 s (grading)
IEC 60947-2 / IEC 60255
IT feeder 4
50/51/51N (MCCB)
Ir 132 A - Im 960 A - Ig 24 A
0.1 s (grading)
IEC 60947-2 / IEC 60255
IT feeder 5
50/51/51N (MCCB)
Ir 132 A - Im 960 A - Ig 24 A
0.1 s (grading)
IEC 60947-2 / IEC 60255
IT feeder 6
50/51/51N (MCCB)
Ir 132 A - Im 960 A - Ig 24 A
0.1 s (grading)
IEC 60947-2 / IEC 60255
+2 more feeders
50/51/51N (MCCB)
per feeder load
0.1 s (grading)
IEC 60947-2
Settings are illustrative starting points — confirm with a protection coordination study per IEC 60255 / IEEE 242.
📚 Calculation book
CALCULATION BOOK
630 kVA - 10kV/0.4kV - N+1 - illustrative
1. Load calculation
Standard: IEC 60076 - IEC 60364-5-52
Parameter
Formula
Value
Connected load
P = sum(kW)
632 kW
Demand factor
Kd
0.9
Demand power
Pd = P x Kd
569 kW
Power factor
cos(phi) before -> after
0.95 -> 0.95
Design apparent power
Sd = Pd / cos(phi)
599 kVA
Transformer loading
Sd / Srated
95%
2. Short-circuit calculation
Standard: IEC 60909
Parameter
Formula
Value
System impedance (pu)
Zs = S / Ssc
0.13% (on 630 kVA base)
Transformer impedance
Zt = Z%
6%
Total impedance
Z = Zt + Zs
6.13%
LV prospective Isc
Isc = In / Z
14.8 kA
HV prospective Isc
Isc = Ssc / (sqrt(3) x V)
28.9 kA
Breaking check
Icu >= Isc
LV 25 kA (1.7x margin) PASS
3. Voltage drop
Standard: IEC 60364-5-52 Annex G
Parameter
Formula
Value
Main feeder
dU = sqrt(3) x I x L x R / V
300 mm2 - dU 0.89% @ 60 m
Limit
max 3%
within limit
Transformer volt. reg.
dU ~ loading x Z% x sin(phi)
1.8% at full load
4. Reactive power / harmonics
Standard: IEC 61921 (PFC) - IEEE 519 (harmonics)
Parameter
Formula
Value
Required compensation
Qc = Pd x (tan1 - tan2)
0 kvar
PFC bank
standard step
0 kvar
Detuned reactor
p = 6%
n/a
5. Grounding
Standard: IEC 60364-5-54 earthing arrangements and protective conductors LV earthing target 10 ohm (TN systems); 4 ohm used as a conservative design target - target 4 ohm
Parameter
Formula
Value
Single rod resistance
R1 = rho/(2 x pi x L) x ln(4L/d)
39.6 ohm
Rods required
n = R1 / (target x 0.8)
13 rod(s) <= 4 ohm
Rod spec
dia x length
20 mm x 2.5 m
This calculation book is illustrative it consolidates the computed values with the referenced standards. A licensed engineer must verify and seal final design documents for construction.
🔧 Secondary schematic (control & signal)
🔩 Terminal strip (typical)
🔋 UPS system
Parameter
Value
UPS module capacity
500 kVA (450 kW @ 0.9 PF)
Redundancy topology
N+1 → 2 module(s) across 1 path(s)
UPS efficiency basis
92% (online double-conversion)
Battery autonomy
10 min → ≈ 72 kWh
🌡️ PUE & efficiency
Parameter
Value
PUE (computed)
1.58 = total facility load ÷ IT load
Rack density
6 kW/rack → 67 racks
Reference range
1.2–1.6 typical; GB 50174 / Uptime Institute recommend monitoring and minimizing
Cable & grounding pricing:Cable conductors and grounding are priced from the confirmed cables-trays-grounding price reference (per-metre copper YJV; aluminium remains POA). The main copper busbar is POA — its length is project-specific.
Busway (high-current feeders):For LV feeders above ~2500 A, a busway (母线槽) trunking system is recommended instead of parallel cables.
PUE estimate:Computed PUE 1.58 (typical modern data centers 1.2–1.6; actual depends on cooling technology and climate).
UPS pricing:Data-center UPS modules are quoted per project — the online catalogue covers 1–3 kVA units, so these are shown POA.
UPS battery bank:A 72 kWh battery bank provides 10 min autonomy at full IT load — sized separately and quoted per project.
DCIM & rack PDU:DCIM monitoring and per-rack PDUs (列头柜/rack PDU) provide power metering and branch monitoring — quoted per project.
Tier & redundancy:Uptime Tier II requires N+1 minimum redundancy; you selected N+1. N+1 → one spare module per system, single path (concurrent maintainability).
UPS battery autonomy:10 min runtime at full IT load ≈ 72 kWh battery (sized separately, quoted per project).
Rack density:6 kW/rack → 67 racks. Within typical air-cooled range.
计算过程说明
选型计算方式
总设施负载 P = IT 负载 + 制冷(占 IT 的百分比)+ 辅助负载(约 8%)。UPS 视在功率 S = IT ÷ (PF × η),在线双变换机组的 η ≈ 0.92。变压器 kVA 按总设施需求的目标功率因数选型,然后由冗余(N / N+1 / 2N)确定并联机组数量和独立供电路径数。PUE = 总设施负载 ÷ IT 负载。
适用标准
选型参考 GB 50174(数据中心设计规范)、TIA-942、Uptime Institute 等级评定、IEC 62040(UPS)和 GB 50052(供电设计)。
常见问题
数据中心供电的 N+1 和 2N 冗余有什么区别?
N+1 是在最小配置外多加一个备用模块(如需要 3 台 UPS 时配 4 台),能承受单点故障。2N 是把整条供电路径复制成两路独立电源、各自能带满负荷,任何单点故障都不影响运行。2N 投资约为翻倍,N+1 增加约 25-35%。Tier III 常对应 N+1,Tier IV 对应 2N。
如何按 IT 负载选数据中心 UPS 容量?
以 IT 负载 kW 为起点,加冷却与机械负载(典型为 IT 负载的 50-70%),留 20-30% 扩容裕量,再按 0.9-0.95 功率因数折算 kVA。1000 kW IT + 60% 冷却 ≈ 1600 kW,约 1700-1780 kVA,故选 2000 kVA UPS。计算器按此流程并匹配标准 UPS 容量。
现代数据中心的 PUE 应做到多少?
PUE = 总设施功率 ÷ IT 功率。传统机房 1.6-1.8,现代风冷数据中心 1.3-1.4,带自然冷却的超大规模可到 1.1-1.2。PUE 每降 0.1,非 IT 能耗约降 10%。TIA-942 与 Uptime Institute 都将 PUE 作为关键效率指标;计算器输出设施/IT 负荷拆分。