Elkraftingenjör Study Notes
These comprehensive study notes cover the core pillars of an Elkraftingenjör
(Electrical Power Engineer) curriculum. They balance theoretical foundations
with Swedish regulatory and field frameworks.
1. Fundamental Power Engineering & Circuit Analysis (Ellära &
Elkraft)
• Three-Phase Systems (Trefassystem):
◦ Line vs. Phase: Line voltage (UL) is measured between two
phases (400 V). Phase voltage (UP) is measured between one
phase and neutral (230 V). UL = √3 × UP.
◦ Configurations: Y-connection (Y-koppling) shares a common
neutral point where IL = IP. Delta-connection (D-koppling) has no
neutral, where IL = √3 × IP.
• Power Triangles (Effekt):
◦ Active Power (P): Measured in Watts (W). P = √3 × UL × IL ×
cos(φ)
◦ Reactive Power (Q): Measured in Volt-Amps Reactive (VAr). Q =
√3 × UL × IL × sin(φ)
◦ Apparent Power (S): Measured in Volt-Amps (VA). S = √3 × UL × IL
= √(P² + Q²)
◦ Power Factor (cos φ): The efficiency ratio of active power to total
apparent power (P/S).
2. Grid Infrastructure & Equipment (Anläggningar &
Elmaskiner)
• Grid Hierarchy (Eldistributionsnät):
◦ Transmission (Stamnät): 220 kV - 400 kV (managed nationally by
Svenska kraftnät).
◦ Regional (Regionalnät): 40 kV - 130 kV.
◦ Distribution (Lokalnät): Low/Medium voltage 0.4 kV - 20 kV
feeding homes and commercial facilities.
• Transformers (Transformatorer): Used to step voltage up or down
based on winding ratios.
◦ Formula: U₁ / U₂ = N₁ / N₂ = I₂ / I₁
• Electrical Machines (Elmaskiner): Focus on asynchronous induction
motors (Asynkronmotorer) and synchronous generators
(Synkrongeneratorer) used in wind and hydro power generation.
3. Swedish Standards & Safety Regulations (Regler,
Standarder & ESA)
• ESA (Elsäkerhetsanvisningarna): Mandatory safety provisions
governing work on or near electrical systems. Key highlights include:
◦ Control Functions: Clear distinction between the Operations
Manager (Elanläggningsansvarig) and the Work Leader
(Elsäkerhetsledare).
◦ 5 Safety Rules for De-energizing: Disconnect completely →
Secure against reconnection → Verify system is dead → Carry out
earthing and short-circuiting → Provide protection against adjacent
live parts.
• EBR (ElnätsBranschens Riktlinjer): Industry guidelines in Sweden
standardizing grid construction, project accounting, and component
requirements.
• Authorized Electrician (Auktoriserad Elinstallatör): The academic
material satisfies the theoretical criteria required by Elsäkerhetsverket for
AL/A (Full Authorization) licenses.
4. Calculations & Design (Nätberäkningar & Elkonstruktion)
• Dimensioning (Dimensioneringsregler): Cables must be sized to
manage thermal load limits, satisfy maximum allowable voltage drop
(typically <4%), and clear short circuits safely.
• Short-Circuit Calculations (Kortslutningsberäkningar): Calculating
prospective fault currents (Ik) to verify that protective fuses or circuit
breakers trip quickly enough to prevent grid damage.
• Relay Protection (Reläskyddssystem): Systems like overcurrent
protection (överströmsskydd) and differential protection (differentialskydd)
designed to isolate grid faults instantly.
5. Essential Design & Engineering Toolset
• CAD & GIS Software: Modern network modeling relies heavily on tools
like elMaster, Febdock (for low voltage calculation), and AutoCAD/
ArcGIS to map, draft, and document network lines geographically.