Can I use the drawing for a real project?

As a starting point for layout and layers, yes. The ratings, settings and cable sizes are made up, so the diagram has to be checked and changed for your project before it is used for design or construction.

Why are the layers coloured?

Colours and line weights follow the layers: power circuits are red and heavy, control is cyan, signal is green. The plot style table in the ZIP prints everything black and keeps the line weights, so you can plot in black and white as well.

Which CAD programs open it?

The drawing and the template are in AutoCAD 2018 format, which AutoCAD 2018 and later open, and so do other CAD programs that read this format. The browser viewer needs nothing installed.

Kaynaklar Tek hat şeması sembolleri

Substation single-line diagram: sample DWGs and electrical template

Complete single-line diagrams of a substation on an ISO A3 sheet, drawn two ways: a 10/0.4 kV substation with a single busbar, and a 10 kV double busbar switchboard with two sections, a bus coupler and two incomers. Each has a protection schedule, a legend and a filled-in title block. All symbols are blocks from the power system single-line symbol library, with tags and ratings filled in.

Free to use and modify in your own projects, including commercial ones. The ZIP holds the sample drawing, a template, a plot style table and a README; no add-in needed. The data in the drawing is made up, so it is not for design or construction. Provided as is, without warranty.

Single busbar

One 10 kV busbar feeding two 1.6 MVA transformers and a voltage transformer, with a 0.4 kV board in two sections joined by a bus coupler and eight feeders.

Download ZIP Tarayıcıda önizle

Double busbar

A 10 kV switchboard with two busbars, each split into section I and section II by a section breaker. Two incomers, a bus coupler between the busbars, every bay on both busbars through two disconnectors, and four outgoing bays.

Download ZIP Tarayıcıda önizle

This sample uses these resources

The symbols are blocks from our own libraries, with their attributes filled in. The sheet and its title block come from our ISO A3 title block template. Download them to draw your own diagrams.

What is in the ZIP

Substation-Single-Busbar-Sample.dwg
Sample drawing (DWG, AutoCAD 2018 format)
Substation-Double-Busbar-Sample.dwg
Sample drawing (DWG, AutoCAD 2018 format)
Electrical-Template-ISO-A3.dwt
Template (DWT) that the drawing was made on
CADXChange-Monochrome.ctb
Plot style table (CTB) that prints every colour black
README.txt
README with the layer list and how to use the files

Every ZIP holds its own drawing together with the template, the plot style table and the README.

The template

The electrical template has 16 layers with colours, line weights and linetypes (power circuits, busbars, control, signal, protective earth, enclosure boundaries, text and more), the text styles ISO-2.5 to ISO-5, the dimension style ISO-25 and an ISO A3 layout with a title block and revision table. The layer names are a common convention, not a standard; rename them to match your company's rules.

Layers defined

Every layer in the template with its colour, line weight and linetype, and how many objects of this sample are on it. Layers the sample does not use are still defined, ready for your own drawing.

Layer	Colour	Line weight	Linetype	Used for	Single busbar	Double busbar
Electrical layers
ELEC-POWER	1	0.50 mm	Continuous	Main power circuits	37	64
ELEC-BUS	1	0.70 mm	Continuous	Busbars and heavy lines	4	5
ELEC-CONTROL	4	0.25 mm	Continuous	Control circuits	not used here	not used here
ELEC-SIGNAL	3	0.18 mm	Continuous	Signal, instrumentation and communication circuits	not used here	not used here
ELEC-PE	2	0.35 mm	Continuous	Protective earth and bonding	not used here	not used here
ELEC-CABLE	30	0.25 mm	DASHED	Cable, conduit and tray routes	not used here	not used here
SYMBOL	7	0.25 mm	Continuous	Symbols (the layer the symbol libraries use)	35	40
ELEC-TERMINAL	7	0.25 mm	Continuous	Terminals and connection points	not used here	not used here
ELEC-BOUNDARY	5	0.18 mm	DASHDOT	Enclosure, panel and device boundaries	2	not used here
ELEC-MECH-LINK	8	0.18 mm	DASHED	Mechanical links, interlocks and measuring links	4	3
ELEC-REF	7	0.18 mm	Continuous	Reference designations (-QF1, -K2)	not used here	not used here
ELEC-WIRE-NO	7	0.18 mm	Continuous	Wire numbers and cable labels	8	not used here
ELEC-XREF	9	0.13 mm	Continuous	Contact and cross reference texts	not used here	not used here
ELEC-TEXT	7	0.18 mm	Continuous	General text	41	31
ELEC-NOTES	7	0.18 mm	Continuous	Notes and legends	4	4
ELEC-DIM	3	0.18 mm	Continuous	Dimensions	not used here	not used here
Sheet and symbol layers
0	7	default	Continuous	Default layer, keep it empty	not used here	not used here
FRAME	7	default	Continuous	Sheet border	5	5
TITLEBLOCK	7	default	Continuous	Title block and revision table	1	1
VIEWPORT	8	default	Continuous	Layout viewport frame (does not plot)	2	2
DRAWING-AREA	8	default	Continuous	Boundary of the model drawing area (does not plot)	2	2

Styles defined

The text styles, the dimension style and the linetypes that the template defines, so you do not have to set them up in each new drawing.

Kind	Name	Settings
Text style	ISO	isocp.shx, 15°, variable height
Text style	ISO-2.5	isocp.shx, 15°, 2.5 mm high
Text style	ISO-3.5	isocp.shx, 15°, 3.5 mm high
Text style	ISO-5	isocp.shx, 15°, 5 mm high
Text style	TB-en	Arial, used by the title block
Dimension style	ISO-25	Text 2.5 mm, arrows 2.5 mm, extension lines 1.25 mm beyond the dimension line and 0.625 mm from the object, dimension lines 3.75 mm apart, 0 decimals
Linetype	Continuous	Solid line
Linetype	DASHED	Dashed
Linetype	DASHDOT	Dash-dot
Linetype	CENTER	Centre line
Linetype	PHANTOM	Phantom line
Linetype	HIDDEN	Hidden line

Sheet and drawing setup

How the sheet is set up, so your own drawings print the same way.

Sheet: ISO A3 landscape, 420 × 297 mm.
Layout: One layout named ISO-A3, plotted at 1:1 on full-bleed A3 media, so the sheet has no printer margin.
Border: 20 mm from the left edge (binding side) and 10 mm from the other edges; the drawing area inside is 390 × 277 mm.
Model space: Units are millimetres. The drawing area is shown at 1:1, so 1 mm in the drawing is 1 mm on paper.
Title block: 160 × 79 mm at the lower right, with a four-line revision table above the company, project, title and approval fields.
Text size: 2.5 mm for labels and notes, 3.5 mm and 5 mm for headings.
Linetype scale: 1, so dashes are sized for plotting at 1:1.
Plot style: None set. Pick the CTB from the ZIP in the page setup for black-and-white plots.

Single busbar

Title block fields

The attributes of the title block. Double-click it to fill them in, or write them for a whole set of drawings with BlockSync.

Attribute	Field on the sheet	Value in this sample
COMPANY	COMPANY	CADXChange
PROJECT	PROJECT	10/0.4 kV Distribution Substation
AREA	AREA	Substation
SYSTEM	SYSTEM	10 kV / 0.4 kV
CLIENT	CLIENT	Sample
TITLE	DRAWING TITLE	Single-line diagram
DRAWING_NO	DRAWING NO.	E-001
CONTRACT_NO	CONTRACT NO.	—
REV	REV	A
DRAWN	DRAWN	—
CHECKED	CHECKED	—
APPROVED	APPROVED	—
DATE	DATE	2026-10-20
SCALE	SCALE	NTS
SHEET	SHEET	1
SHEET_OF	OF	1

Revision table: R1 to R4, each with REV, DATE, DESCRIPTION and BY (16 attributes, empty in this sample).

Blocks in the drawing

The equipment list of the drawing: block name, symbol and how many times it is placed. BlockSync exports the same list from your own drawings.

Symbol	Block	Placed
Moulded case circuit breaker	PWR_LV_MCCB	8
Motor, induction	PWR_MOTOR_IM	4
Circuit breaker, vacuum	PWR_CB_VCB	3
Current transformer	PWR_CT	3
Relay, overcurrent (50/51)	PWR_R_5051	3
Load (static)	PWR_LOAD	3
Transformer, delta-star, neutral earthed	PWR_TX_DYN	2
Air circuit breaker	PWR_CB_ACB	2
Grid infeed (utility source)	PWR_GRID	1
Disconnector	PWR_DISCONNECTOR	1
Fuse	PWR_FUSE	1
Voltage transformer	PWR_VT	1
Earth	PWR_EARTH	1
Bus tie breaker	PWR_BUS_TIE	1
Power factor correction	PWR_LV_PFC	1

Equipment schedule

One row per placed symbol, read from the attributes of the blocks in the drawing: what is shown on the sheet, and the schedule attributes that were filled in but are not shown. BlockSync exports these same attributes from your own drawings.

Tag	Description	Shown on the sheet	Filled in, not shown
G1	Grid infeed (utility source)PWR_GRID	RATING = 250 MVA	VOLTAGE_KV = 10
QS1	DisconnectorPWR_DISCONNECTOR	RATED_KV = 12 kV	RATED_CURRENT_A = 630SHORT_TIME_KA = 25EARTHING_SWITCH = NoMECHANISM = Manual
QF1	Circuit breaker, vacuumPWR_CB_VCB	RATED_KV = 12 kV	RATED_CURRENT_A = 630BREAKING_KA = 25INTERRUPTER = VacuumMECHANISM = SpringCONTROL_VOLTAGE = 110 V DC
TA1	Current transformerPWR_CT	RATIO = 200/1 A	CLASS = 5P20BURDEN_VA = 15CORES = 2RATED_KV = 12
F1	Relay, overcurrent (50/51)PWR_R_5051	FUNCTION = OC / EF	SETTING = I> 1.2 In, 0.3 s; I>> 8 In, 0.1 sTRIPS = QF1CT_INPUT = TA1
QF2	Circuit breaker, vacuumPWR_CB_VCB	RATED_KV = 12 kV	RATED_CURRENT_A = 630BREAKING_KA = 25INTERRUPTER = VacuumMECHANISM = SpringCONTROL_VOLTAGE = 110 V DC
TA2	Current transformerPWR_CT	RATIO = 100/1 A	CLASS = 5P20BURDEN_VA = 15CORES = 2RATED_KV = 12
T1	Transformer, delta-star, neutral earthedPWR_TX_DYN	RATING_MVA = 1.6 MVA	VOLTAGE_RATIO = 10/0.4 kVVECTOR_GROUP = Dyn11IMPEDANCE_PCT = 6TAP_RANGE = +/-2x2.5%COOLING = ONANNEUTRAL_EARTHING = Solid
QF4	Air circuit breakerPWR_CB_ACB	RATED_KV = 0.69 kV	RATED_CURRENT_A = 2500BREAKING_KA = 50INTERRUPTER = AirMECHANISM = Motor-charged springCONTROL_VOLTAGE = 110 V DC
F2	Relay, overcurrent (50/51)PWR_R_5051	FUNCTION = OC / EF	SETTING = I> 1.1 In, 0.4 s; I>> 7 In, 0.1 sTRIPS = QF2CT_INPUT = TA2
QF3	Circuit breaker, vacuumPWR_CB_VCB	RATED_KV = 12 kV	RATED_CURRENT_A = 630BREAKING_KA = 25INTERRUPTER = VacuumMECHANISM = SpringCONTROL_VOLTAGE = 110 V DC
TA3	Current transformerPWR_CT	RATIO = 100/1 A	CLASS = 5P20BURDEN_VA = 15CORES = 2RATED_KV = 12
T2	Transformer, delta-star, neutral earthedPWR_TX_DYN	RATING_MVA = 1.6 MVA	VOLTAGE_RATIO = 10/0.4 kVVECTOR_GROUP = Dyn11IMPEDANCE_PCT = 6TAP_RANGE = +/-2x2.5%COOLING = ONANNEUTRAL_EARTHING = Solid
QF5	Air circuit breakerPWR_CB_ACB	RATED_KV = 0.69 kV	RATED_CURRENT_A = 2500BREAKING_KA = 50INTERRUPTER = AirMECHANISM = Motor-charged springCONTROL_VOLTAGE = 110 V DC
F3	Relay, overcurrent (50/51)PWR_R_5051	FUNCTION = OC / EF	SETTING = I> 1.1 In, 0.4 s; I>> 7 In, 0.1 sTRIPS = QF3CT_INPUT = TA3
FU1	FusePWR_FUSE	RATED_KV = 12 kV	RATED_CURRENT_A = 6BREAKING_KA = 50CHARACTERISTIC = Current limiting
TV1	Voltage transformerPWR_VT	RATIO = 10/0.1 kV	CLASS = 0.5BURDEN_VA = 50WINDINGS = 2RATED_KV = 12
E1	EarthPWR_EARTH	EARTH_TYPE = PE
QF6	Bus tie breakerPWR_BUS_TIE	VOLTAGE_KV = 0.4	RATED_CURRENT_A = 2000CONDUCTOR = Copper busbarSHORT_CIRCUIT_KA = 50
QM11	Moulded case circuit breakerPWR_LV_MCCB	RATED_CURRENT_A = 125 A	VOLTAGE = 400 VBREAKING_KA = 36TRIP_UNIT = Thermal-magneticPOLES = 3
M1	Motor, inductionPWR_MOTOR_IM	POWER_KW = 30 kW	VOLTAGE = 400 VPOWER_FACTOR = 0.85STARTING = Star-deltaSERVICE = Feed pump P-101
QM12	Moulded case circuit breakerPWR_LV_MCCB	RATED_CURRENT_A = 125 A	VOLTAGE = 400 VBREAKING_KA = 36TRIP_UNIT = Thermal-magneticPOLES = 3
M2	Motor, inductionPWR_MOTOR_IM	POWER_KW = 75 kW	VOLTAGE = 400 VPOWER_FACTOR = 0.85STARTING = Star-deltaSERVICE = Cooling fan F-201
QM13	Moulded case circuit breakerPWR_LV_MCCB	RATED_CURRENT_A = 125 A	VOLTAGE = 400 VBREAKING_KA = 36TRIP_UNIT = Thermal-magneticPOLES = 3
L1	Load (static)PWR_LOAD	POWER_KW = 20 kW	VOLTAGE = 400 VPOWER_FACTOR = 0.95SERVICE = Lighting LP-1
QM14	Moulded case circuit breakerPWR_LV_MCCB	RATED_CURRENT_A = 125 A	VOLTAGE = 400 VBREAKING_KA = 36TRIP_UNIT = Thermal-magneticPOLES = 3
C1	Power factor correctionPWR_LV_PFC	RATED_CURRENT_A = 100 kvar	VOLTAGE = 400 VBREAKING_KA = 36TRIP_UNIT = Thermal-magneticPOLES = 3
QM15	Moulded case circuit breakerPWR_LV_MCCB	RATED_CURRENT_A = 125 A	VOLTAGE = 400 VBREAKING_KA = 36TRIP_UNIT = Thermal-magneticPOLES = 3
M3	Motor, inductionPWR_MOTOR_IM	POWER_KW = 55 kW	VOLTAGE = 400 VPOWER_FACTOR = 0.85STARTING = Star-deltaSERVICE = Compressor K-301
QM16	Moulded case circuit breakerPWR_LV_MCCB	RATED_CURRENT_A = 125 A	VOLTAGE = 400 VBREAKING_KA = 36TRIP_UNIT = Thermal-magneticPOLES = 3
L2	Load (static)PWR_LOAD	POWER_KW = 40 kW	VOLTAGE = 400 VPOWER_FACTOR = 0.95SERVICE = Heating HP-1
QM17	Moulded case circuit breakerPWR_LV_MCCB	RATED_CURRENT_A = 125 A	VOLTAGE = 400 VBREAKING_KA = 36TRIP_UNIT = Thermal-magneticPOLES = 3
L3	Load (static)PWR_LOAD	POWER_KW = 60 kW	VOLTAGE = 400 VPOWER_FACTOR = 0.95SERVICE = Process PP-1
QM18	Moulded case circuit breakerPWR_LV_MCCB	RATED_CURRENT_A = 125 A	VOLTAGE = 400 VBREAKING_KA = 36TRIP_UNIT = Thermal-magneticPOLES = 3
M4	Motor, inductionPWR_MOTOR_IM	POWER_KW = 37 kW	VOLTAGE = 400 VPOWER_FACTOR = 0.85STARTING = Star-deltaSERVICE = Mixer A-401

Manufacturer, model and remarks are left empty on every block, ready for your data. The values are examples.