Summary of "دورة اعداد مهندس كهرباء موقع - الدرس السادس ما هو (ups) ؟"

Summary of Video: دورة اعداد مهندس كهرباء موقع - الدرس السادس ما هو (UPS) ؟

Main Topic

Explanation of the UPS (Uninterruptible Power Supply) system, its components, types, functions, and integration with other power backup systems like the ETS (Automatic Transfer Switch) and diesel generators.

Key Concepts and Lessons

Introduction and Context

Recap of previous lesson on ETS (Automatic Transfer Switch), which automatically transfers power to an emergency panel during a power outage.
Today’s focus is on the UPS, a critical device used in large projects to ensure uninterrupted power to extremely important loads.

What is a UPS?

UPS stands for Uninterruptible Power Supply.
It is used to maintain continuous electrical power to critical loads that cannot tolerate any power interruption (e.g., server rooms, monitoring systems, bank computers).
The UPS prevents power cuts from affecting these loads under any circumstances.

Basic Components of a UPS

Rectifier: Converts incoming AC (Alternating Current) from the main power source into DC (Direct Current).
Batteries: Store DC power and supply it when the main power is interrupted.
Inverter: Converts DC power from the batteries back into AC power to feed the loads.

Types of UPS

Standby UPS
Line-interactive UPS
Online UPS
Hybrid Standby
Ferro Standby
Online Cover
Delta Standby

Note: Understanding the function and purpose of UPS is more important than memorizing types.

Critical Loads for UPS

Server rooms
Monitoring rooms or screens
Bank computers and servers
Any load where power interruption is unacceptable

UPS Operation During Power Outage

When main power cuts off, the rectifier stops charging the batteries.
Batteries supply DC power to the inverter, which converts it to AC to keep the loads running without interruption.
The duration the UPS can supply power depends on:
- Battery capacity (measured in ampere-hours)
- Load current drawn
Key UPS specifications to consider when purchasing:
- Maximum current it can supply
- Duration it can supply power during outage

Integration with ETS and Backup Generators

UPS covers the short period immediately after power failure to avoid any interruption.
ETS switches power source from the main grid to the backup diesel generator.
Once the diesel generator starts, it supplies power to the UPS, which recharges the batteries and continues feeding the loads.
When main power returns, ETS switches back from the generator to the main grid, and the cycle repeats.

Summary of Power Flow During Outage

Main power fails.
UPS batteries instantly supply power via inverter to critical loads.
ETS starts diesel generator and switches load to generator.
Generator supplies power, rectifier charges batteries, inverter feeds loads.
When main power returns, ETS switches back to main power source.

Final Notes

Understanding UPS operation is essential for electrical engineers working on projects involving critical loads.
The instructor encourages students to ask questions if unclear and emphasizes the importance of fully understanding the material before moving on.

Detailed Methodology and Instructions

To understand UPS operation:
- Know the three main components: rectifier (AC→DC), batteries (store DC), inverter (DC→AC).
- Identify critical loads that require UPS protection.
- Recognize the importance of battery capacity and load current in determining UPS size and backup duration.
- Understand the interaction between UPS, ETS, and backup generators during power outages.
- Remember that UPS covers the immediate power gap until the generator starts and takes over.
- When selecting a UPS, specify:
  - Maximum current capacity
  - Backup duration (how long it can supply power)
Practical operation sequence during power failure:
- Power outage → UPS battery powers load instantly → ETS starts generator → ETS switches load to generator → Generator powers UPS and charges batteries → Main power returns → ETS switches back to main power.