A 19-chapter, 38-slide interactive guide to power systems engineering — transmission and grid interconnection at 230–500 kV, 13.8 kV distribution feeder and underground loop design, hospital/mall/campus facility power systems, solar and flow-battery renewable interconnection, and advanced grid concepts including HVDC protection, microgrid black start and islanding, smart-city grids, and peer-to-peer nanogrid energy trading. Every reference one-line diagram gets its own full-size slide so voltages, equipment ratings, and protection schemes stay legible.
Chapters 1–4 cover transmission and grid interconnection: interconnected multi-plant grids, separate 500 kV/230 kV networks, 230 kV transmission line protection with distance relays and permissive tripping, and a full utility interconnection one-line down to the life-safety interface. Chapters 5–8 cover distribution systems: the utility-to-loads distribution hierarchy, 13.8 kV feeder one-lines, underground loop distribution for reliability, and a storm-hardened coastal city feeder system with FLISR and a microgrid cluster. Chapters 9–12 apply these principles to facility and campus power systems — a hospital standby generator, two shopping mall distribution designs (IEC 415 V and NEC 480 V), and a university campus ring-bus power system. Chapters 13–15 cover renewable energy and storage integration: a 50 MW solar farm interconnection, a 50 MW/300 MWh flow battery plant, and a smart residential community with solar, EV charging, and battery storage. Chapters 16–19 close with advanced grid and resilience concepts: HVDC and inverter-based resource protection, a hospital microgrid with black start and islanding, a smart city grid with AMI and grid-of-grids, and a hybrid AC/DC future grid with nanogrids and peer-to-peer energy trading.
Use the Prev / Next buttons at the bottom, or press the arrow keys on your keyboard. Click the ☰ menu button in the top-right to open the table of contents and jump to any of the 19 chapters. Each chapter's one-line diagram follows immediately after its text as its own dedicated slide, so you can view the full drawing at a readable size — voltage levels, equipment ratings, and protection settings included — before moving to the next chapter.
Electrical and power systems engineers who want a structured reference spanning transmission through distribution to facility-level design; PE Power exam candidates reviewing grid interconnection, protection coordination, and renewable/storage integration; and engineering students learning how one-line diagrams represent real transmission, distribution, and microgrid systems — from a 500 kV transmission corridor down to a 380 V DC nanogrid.
Transmission typically runs 230–500 kV for bulk, long-distance power transfer between plants and regions. Sub-transmission steps that down to roughly 69–115 kV to feed local distribution areas. Primary distribution is commonly 4.16–34.5 kV (13.8 kV is a frequent choice) for neighborhood- and facility-level feeders, and secondary distribution steps down to 120/240 V or 480/277 V at the point of use.
A feeder disconnector taps a 13.8 kV substation or generation bus, and individually breakered feeders (typically 15 kV class, 1200 A, 25 kA) carry power to specific loads or areas. Loop (ring) configurations connect multiple feeders and transformers together so a fault on one segment can be isolated while an alternate path keeps every downstream customer powered — a design covered in this guide for both a simple radial feeder set and a full underground loop system.
A standby generator connects through an automatic transfer switch (ATS) that senses loss of utility power and transfers only the critical-load side of the building — life safety, emergency, and critical care systems per NFPA 99/110 — to generator power. A full microgrid design goes further, adding solar, battery storage, and a microgrid controller so the facility can island from the grid indefinitely and even black-start from a fully de-energized state.
PV blocks or battery inverters feed a medium-voltage collector bus (commonly 34.5 kV), which steps up through a generator step-up transformer to the transmission interconnection voltage (115 kV or higher) at a single point of interconnection (POI) circuit breaker. The whole plant is designed to IEEE 1547-2018 interconnection requirements, with SCADA/RTU protection and control monitoring the collector system and the POI.
Islanding is a microgrid intentionally disconnecting from the main utility grid and continuing to serve its own loads from local generation, solar, and storage. A microgrid controller detects the loss of grid connection, opens the tie breaker, and — if starting from a fully dead bus — can black-start from a diesel generator, bring the battery storage online for voltage/frequency support, then pick up critical loads first and non-critical loads last, closing back to the utility only after a synchronism check confirms it is safe to reconnect.
Disclaimer: This guide summarizes general power systems engineering concepts and illustrative one-line diagrams for educational purposes only. All facilities, ratings, and configurations shown are representative examples, not as-built designs. Always consult a licensed professional engineer and the applicable utility, IEEE, IEC, NESC, and NFPA requirements for actual project design.