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配电系统设计与报价计算器

为任意配电项目选型变压器、HV/LV 开关柜、电缆和接地——基于标准设计（IEC / NEC / GB），并即时生成带 FOB 报价的物料清单。

开始计算

标准

变压器类型 *

总连接负载（kW） *

HV 电压（kV） *

LV 电压（kV） *

平均功率因数 *

回路（馈线）

目标功率因数

需用系数

上游短路容量 Ssc（MVA）

土壤电阻率 ρ（Ω·m）

馈线敷设长度（m）

冗余

绕组

效率 / 系列

HV 开关柜类型

电缆分支箱

高级参数

默认值符合标准设计基准——请根据现场具体条件进行调整。

接地棒长度 (m)

接地棒直径 (mm)

接地目标 (Ω)

电缆导体

电缆相数

最大电压降 (%)

调谐电抗器电抗率 (%)

智能化与监控

在 BOM 中加入 SCADA、综保 IED、直流屏、通信与计量。选「不含」则设计完全不变。

自动化档位

通信协议

工作原理

输入连接负载、电压等级和少量现场参数。计算器会应用需用系数，按标准 kVA 容量选型变压器，选择 HV/LV 开关柜，并校验短路和电压降限值——然后对设备进行报价。

Worked Examples

Example 1 — 500 kW Industrial Distribution System · FOB $45,442

Distribution system · iec standard

500 kVA transformer

S13-M-500/10

Est. total (FOB)

$45,442

📦 Bill of Materials (example)

Equipment	Model	Spec	Qty
HV incoming panel	KYN28A-12-630-315	630 A / 31.5 kA · vacuum	1
Main transformer	S13-M-500/10	500 kVA · Oil-Immersed · Copper · S13	1
LV incoming panel	GGD-1000	1000 A busbar · In 722 A	1
LV feeder panel	GGD-1000	distributes 4 circuits	1
PFC capacitor bank	150 kVAR	automatic · GCK LV cabinet	1
Series reactor (detuned)	CKSG-9.0/0.4	9.0 kVAR · 6% · 0.4 kV	1
Main feeder cable (TX→LV)	YJV 0.6/1kV 240 mm² ×2	2× 240 mm² Cu · ΔU 0.88% @ 60 m · $123.0/m	2
Feeder cable — LV feeder circuit 1 (×4)	YJV 95 mm²	95 mm² Cu · 212 A · ΔU 1.3% · $47.2/m	4
Main busbar (Cu)	Cu 63×6.3	63×6.3 · 900 A rating · ref $47/m	included
Grounding electrode	Φ20mm × 2.5m rod	R₁ 39.6 Ω → 13 rod(s) ≤ 4 Ω	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	231 A	inst	IEC 60255-151 / IEEE 242
HV incoming 10 kV	51 overcurrent	35 A	0.5 s	IEC 60255-151 / IEEE 242
HV incoming 10 kV	51N earth-fault	6 A	0.5 s	IEC 60364-4-41
Transformer 500 kVA	49 thermal overload	84% of rated	alarm 90%	IEC 60076-7 / IEEE C57.91
LV incoming 0.4 kV	50 instantaneous	5774 A	inst	IEC 60947-2
LV incoming 0.4 kV	51 overcurrent	866 A	0.3 s	IEC 60947-2 / IEC 60255
LV incoming 0.4 kV	51N earth-fault	144 A	0.3 s	IEC 60364-4-41
LV feeder circuit 1	50/51/51N (MCCB)	Ir 233 A - Im 1698 A - Ig 42 A	0.1 s (grading)	IEC 60947-2 / IEC 60255
LV feeder circuit 2	50/51/51N (MCCB)	Ir 233 A - Im 1698 A - Ig 42 A	0.1 s (grading)	IEC 60947-2 / IEC 60255
LV feeder circuit 3	50/51/51N (MCCB)	Ir 233 A - Im 1698 A - Ig 42 A	0.1 s (grading)	IEC 60947-2 / IEC 60255
LV feeder circuit 4	50/51/51N (MCCB)	Ir 233 A - Im 1698 A - Ig 42 A	0.1 s (grading)	IEC 60947-2 / IEC 60255

Settings are illustrative starting points — confirm with a protection coordination study per IEC 60255 / IEEE 242.

📚 Calculation book

CALCULATION BOOK

500 kVA - 10kV/0.4kV - single - illustrative

1. Load calculation

Standard: IEC 60076 - IEC 60364-5-52

Parameter	Formula	Value
Connected load	P = sum(kW)	500 kW
Demand factor	Kd	0.8
Demand power	Pd = P x Kd	400 kW
Power factor	cos(phi) before -> after	0.85 -> 0.95
Design apparent power	Sd = Pd / cos(phi)	421 kVA
Transformer loading	Sd / Srated	84%

2. Short-circuit calculation

Standard: IEC 60909

Parameter	Formula	Value
System impedance (pu)	Zs = S / Ssc	0.10% (on 500 kVA base)
Transformer impedance	Zt = Z%	4%
Total impedance	Z = Zt + Zs	4.10%
LV prospective Isc	Isc = In / Z	17.6 kA
HV prospective Isc	Isc = Ssc / (sqrt(3) x V)	28.9 kA
Breaking check	Icu >= Isc	LV 25 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	240 mm2 - dU 0.88% @ 60 m
Limit	max 3%	within limit
Transformer volt. reg.	dU ~ loading x Z% x sin(phi)	1.1% at full load

4. Reactive power / harmonics

Standard: IEC 61921 (PFC) - IEEE 519 (harmonics)

Parameter	Formula	Value
Required compensation	Qc = Pd x (tan1 - tan2)	116 kvar
PFC bank	standard step	150 kvar
Detuned reactor	p = 6%	9.0 kvar @ 6% (anti-resonance)

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)

📏 Standard basis (依据标准)

Topic	Standard
Standard basis	IEC · IEC 60364-5-52
Conductor ampacity	IEC 60364-5-52 Table B.52.2–B.52.5 (copper, 3 loaded conductors, 30°C ambient, PVC) — typical/rounded values, conservative (±3%)
Voltage-drop limit	IEC 60364-5-52 Annex G · max drop 3%
Winding temp rise	IEC 60076-2 — winding temp rise 65 K (Class A insulation, ONAN)
kVA ratings	IEC 60076-1 R10 preferred numbers
Breaker frames	IEC 60947-2 frame sizes (In)
Grounding target	IEC 60364-5-54 earthing arrangements and protective conductors — LV earthing target ≤ 10 Ω (TN systems); 4 Ω used as a conservative design target · target 4 Ω

🧮 How it was calculated

1. Loads: P=500 kW, PF 0.85, 4 circuits

2. Demand: 500 × 0.8 = 400 kW

3. PFC: Qc = 400 × (0.620 − 0.329) = 116 kVAR → 150 kVAR bank

4. Transformer: S = 400 ÷ 0.95 = 421.1 kVA → 500 kVA standard

4b. Loading: 421 ÷ 500 = 84% (good range)

4c. Voltage regulation: 84% × 4% × sinφ ≈ 1.1% at full load

5. HV: In 28.9 A, Isc 28.9 kA → KYN28A-12-630-315

6. LV: In 722 A, Isc 17.6 kA (Xfmr Z 4% + system 0.1%) → GGD-1000, 1 feeder panel(s)

7. Grounding: R₁ 39.6 Ω → 13 rod(s)

8. Main feeder: 2× 240 mm² · ΔU 0.88% — OK

Example 2 — 800 kW Dry-Type (N+1) Distribution System · FOB $128,552

Distribution system · iec standard

1,000 kVA transformer

SCB13-1000/10

Est. total (FOB)

$128,552

📦 Bill of Materials (example)

Equipment	Model	Spec	Qty
HV incoming panel	KYN28A-12-630-25	630 A / 25 kA · vacuum	2
HV bus-tie panel	KYN28A-12-630-25	630 A / 25 kA · vacuum	1
Main transformer (each)	SCB13-1000/10	1000 kVA · Dry-Type · Aluminum · SCB13	2
LV incoming panel	GGD-1600	1600 A busbar · In 1443 A	2
LV bus-tie panel	GGD-1600	1600 A busbar	1
LV feeder panel (×2)	GGD-1600	distributes 8 circuits	2
PFC capacitor bank	150 kVAR	automatic · GCK LV cabinet	2
Cable branch box (LV)	DFW-0.4	1-in / 4-out · 0.4 kV · 630 A	1
Series reactor (detuned)	CKSG-9.0/0.4	9.0 kVAR · 6% · 0.4 kV	1
Main feeder cable (TX→LV)	YJV 0.6/1kV 240 mm² ×4	4× 240 mm² Cu · ΔU 1.17% @ 80 m · $123.0/m	4
Feeder cable — LV feeder circuit 1 (×8)	YJV 70 mm²	70 mm² Cu · 160 A · ΔU 1.8% · $37.0/m	8
Branch trunk cable (LV → branch box 1)	YJV 185 mm² ×2	2× 185 mm² Cu · 642 A · ΔU 1.4% · $103.0/m	2
Main busbar (Cu)	Cu 100×10	100×10 · 2000 A rating · ref $118/m	included
Grounding electrode	Φ20mm × 2.5m rod	R₁ 59.3 Ω → 19 rod(s) ≤ 4 Ω	19

📐 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	462 A	inst	IEC 60255-151 / IEEE 242
HV incoming 10 kV	51 overcurrent	69 A	0.5 s	IEC 60255-151 / IEEE 242
HV incoming 10 kV	51N earth-fault	12 A	0.5 s	IEC 60364-4-41
Transformer 1000 kVA	87 differential	12 A	inst	IEEE C37.91 / GB/T 14285
Transformer 1000 kVA	49 thermal overload	72% of rated	alarm 90%	IEC 60076-7 / IEEE C57.91
LV incoming 0.4 kV	50 instantaneous	11547 A	inst	IEC 60947-2
LV incoming 0.4 kV	51 overcurrent	1732 A	0.3 s	IEC 60947-2 / IEC 60255
LV incoming 0.4 kV	51N earth-fault	289 A	0.3 s	IEC 60364-4-41
LV bus-tie	50/51 overcurrent	1732 A	0.3 s	IEC 60947-2
LV feeder circuit 1	50/51/51N (MCCB)	Ir 176 A - Im 1283 A - Ig 32 A	0.1 s (grading)	IEC 60947-2 / IEC 60255
LV feeder circuit 2	50/51/51N (MCCB)	Ir 176 A - Im 1283 A - Ig 32 A	0.1 s (grading)	IEC 60947-2 / IEC 60255
LV feeder circuit 3	50/51/51N (MCCB)	Ir 176 A - Im 1283 A - Ig 32 A	0.1 s (grading)	IEC 60947-2 / IEC 60255
LV feeder circuit 4	50/51/51N (MCCB)	Ir 176 A - Im 1283 A - Ig 32 A	0.1 s (grading)	IEC 60947-2 / IEC 60255
LV feeder circuit 5	50/51/51N (MCCB)	Ir 176 A - Im 1283 A - Ig 32 A	0.1 s (grading)	IEC 60947-2 / IEC 60255
LV feeder circuit 6	50/51/51N (MCCB)	Ir 176 A - Im 1283 A - Ig 32 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

1000 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)	800 kW
Demand factor	Kd	0.85
Demand power	Pd = P x Kd	680 kW
Power factor	cos(phi) before -> after	0.90 -> 0.95
Design apparent power	Sd = Pd / cos(phi)	716 kVA
Transformer loading	Sd / Srated	72%

2. Short-circuit calculation

Standard: IEC 60909

Parameter	Formula	Value
System impedance (pu)	Zs = S / Ssc	0.29% (on 1000 kVA base)
Transformer impedance	Zt = Z%	6%
Total impedance	Z = Zt + Zs	6.29%
LV prospective Isc	Isc = In / Z	23.0 kA
HV prospective Isc	Isc = Ssc / (sqrt(3) x V)	20.2 kA
Breaking check	Icu >= Isc	LV 25 kA (1.1x 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	240 mm2 - dU 1.17% @ 80 m
Limit	max 3%	within limit
Transformer volt. reg.	dU ~ loading x Z% x sin(phi)	1.3% at full load

4. Reactive power / harmonics

Standard: IEC 61921 (PFC) - IEEE 519 (harmonics)

Parameter	Formula	Value
Required compensation	Qc = Pd x (tan1 - tan2)	106 kvar
PFC bank	standard step	150 kvar
Detuned reactor	p = 6%	9.0 kvar @ 6% (anti-resonance)

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)	59.3 ohm
Rods required	n = R1 / (target x 0.8)	19 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)

📏 Standard basis (依据标准)

Topic	Standard
Standard basis	IEC · IEC 60364-5-52
Conductor ampacity	IEC 60364-5-52 Table B.52.2–B.52.5 (copper, 3 loaded conductors, 30°C ambient, PVC) — typical/rounded values, conservative (±3%)
Voltage-drop limit	IEC 60364-5-52 Annex G · max drop 3%
Winding temp rise	IEC 60076-11 — dry-type Class F 100 K rise
kVA ratings	IEC 60076-1 R10 preferred numbers
Breaker frames	IEC 60947-2 frame sizes (In)
Grounding target	IEC 60364-5-54 earthing arrangements and protective conductors — LV earthing target ≤ 10 Ω (TN systems); 4 Ω used as a conservative design target · target 4 Ω

🧮 How it was calculated

1. Loads: P=800 kW, PF 0.90, 8 circuits

2. Demand: 800 × 0.85 = 680 kW

3. PFC: Qc = 680 × (0.484 − 0.329) = 106 kVAR → 150 kVAR bank

4. Transformer: S = 680 ÷ 0.95 = 715.8 kVA → 1,000 kVA standard

4b. Loading: 716 ÷ 1,000 = 72% (good range)

4c. Voltage regulation: 72% × 6% × sinφ ≈ 1.3% at full load

5. HV: In 57.7 A, Isc 20.2 kA → KYN28A-12-630-25

6. LV: In 1443 A, Isc 23.0 kA (Xfmr Z 6% + system 0.3%) → GGD-1600, 2 feeder panel(s)

6b. Cable branch boxes: 1 × DFW-0.4 (1-in/4-out) for feeder grouping

7. Grounding: R₁ 59.3 Ω → 19 rod(s)

8. Main feeder: 4× 240 mm² · ΔU 1.17% — OK

计算过程说明

选型依据

变压器 kVA = 需求 kW ÷ 目标功率因数，向上取整至标准容量；电缆截面根据载流量和电压降限值确定；LV 短路电流由变压器阻抗加上上游系统计算得出；接地棒数量根据电极电阻与目标接地电阻确定。

适用标准

设计遵循所选标准中的导体载流量、电压降限值、绕组温升、标准 kVA 容量、断路器框架和接地目标——每项输出均标注其标准依据。

常见问题

低压配电系统中可接受的电压降是多少？

IEC 60364-5-52 建议从电源到负载的总电压降控制在 5% 以内（配电回路 4% + 末级回路 1%），照明回路限值 3%。超过 5% 会导致电机电流增大、过热甚至跳闸，因此馈线选型通常把稳态压降控制在 2-3% 左右，并给电机启动留出裕量。

如何计算配电系统所需的变压器容量（kVA）？

计算需用容量 Sd = 总装机 kW × 需用系数 kd ÷ 目标功率因数。工业厂房 kd 通常 0.6-0.8，商业建筑 0.4-0.6。然后按 IEC 60076 取邻近的标准容量（100/160/250/400/630/800/1000/1250 kVA），使负载率落在 70-80% 左右，兼顾效率与未来扩容。

铜绕组与铝绕组——导体材质对变压器成本和损耗影响多大？

相同容量下铝绕组比铜绕组采购成本低约 15-25%，但负载损耗高约 25-35%，因为铝的电阻率（2.65 μΩ·cm）约为铜（1.68 μΩ·cm）的 1.6 倍。铜变压器体积更小、温升更低，铝变压器首购价占优。本计算器对 S9/S11/S13/S20 系列按铜/铝双材质报价，可直接对比全生命周期成本。

开关柜的短路容量应选多大？

开关柜分断能力要按母线处故障水平校核，由上级短路容量和变压器阻抗算出。10 kV/0.4 kV、1000 kVA、阻抗 6% 的变压器在低压母线约贡献 24 kA，因此应选 31.5 kA 或 36 kA 的柜子而非 16 kA。计算方法见 IEC 60909。

计算器里的 FOB 价格是怎么算出来的？

价格来自 QDTB 定价矩阵（calculator-data.json），变压器按铜价联动因子计算。变压器价格按容量曲线 a·S^b 拟合，铜绕组随每日铜价（基准约 14200 美元/吨）联动，开关柜/补偿按区间定价。总价为青岛 FOB 参考价，含标准附件，不含运费、关税和安装。

工厂负载的需用系数（demand factor）该取多少？

需用系数 kd = 最大同时负荷 ÷ 总装机容量。典型值：连续流程工厂 0.8-0.9、一般制造 0.6-0.7、商业办公 0.4-0.6、住宅 0.3-0.5。取对 kd 可避免变压器超配 30-40% 及其空载损耗；计算器在选标准 kVA 前会先套用 kd。

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