Emergency power systems are essential for providing reliable power support when normal power supply fails or is interrupted, ensuring the continuous operation of critical equipment and facilities. These systems prevent significant losses and impacts, making them a crucial component of power assurance. Typically, an emergency power system comprises various power devices and associated control, switching, and monitoring equipment. Common emergency power devices include diesel generators, which have robust power generation capabilities and can independently supply power to critical loads when the main power supply is unavailable. Below is an overview of the types of emergency power systems and key design considerations.

Types of Emergency Power Sources:

Independent Power Generators Separate from Normal Power Supply:

Among emergency power options, generators independent of the normal power supply play a vital role. Emergency gas turbine generators, known for their efficiency and quick response, are highly regarded, while emergency diesel generators are commonly chosen for their reliability and broad applicability. Quick-start generators are especially suitable for power supply scenarios that allow for a power interruption time of more than 15 seconds.

Example: In large industrial plants, when normal power fails, these generators can quickly start up, providing continuous power to critical equipment and ensuring that production processes are not disrupted, thereby avoiding significant economic losses.

UPS (Uninterruptible Power Supply):

The UPS is a highly sophisticated and efficient emergency power device. It is suitable for loads that allow for power interruption times in the millisecond range. Its outstanding quick response capability enables instantaneous switching to an alternate power supply, ensuring that equipment requiring high power stability, such as financial transaction systems and life support systems in medical equipment, is not affected in any way.

Example: In a hospital operating room, the UPS can instantly provide power when even the slightest interruption in the main power supply occurs, ensuring that surgeries proceed smoothly and protecting patient safety.

EPS (Emergency Power Supply):

EPS is a unique emergency power supply that inverts the DC power from batteries into AC power. It is suitable for loads that allow for power interruption times of 0.25 seconds or more. Compared to UPS, its structure and operating principles are somewhat simpler.

Example: In small shopping malls, EPS systems can quickly activate during a power failure, providing sufficient lighting for evacuation routes and important areas, guiding people to safety.

Dedicated Feeder Lines with Automatic Transfer Devices Independent of Normal Power:

This emergency power method has a unique advantage and is suitable for loads that allow for power interruption times of 1.5 seconds or 0.6 seconds or more. In large data centers, such dedicated feeder lines can quickly come into operation when there is an issue with the main power supply, ensuring the normal operation of servers and storage devices, preventing data loss and business interruptions.

Batteries:

Batteries, used as emergency power, are suitable for particularly important loads with small capacities and play a crucial role where DC power sources can be used.

Example: In remote communication base stations, batteries can provide short but critical power support to base station equipment when the main power is interrupted, ensuring smooth communication.

Key Points of Emergency Power System Design:

Careful Evaluation of Critical Loads:

In engineering design, for critically important loads proposed by other disciplines, it is necessary to carefully evaluate and minimize the load as much as possible, except for those requiring dual security measures.

Example: In a smart office building design, multiple departments may request high-reliability power supply for specific equipment or systems. By carefully analyzing their actual operational needs and importance, the load can be optimized to ensure that truly critical equipment is adequately protected.

Avoiding Non-Critical Loads in Emergency Power Systems:

To ensure power supply to critical loads, it is strictly prohibited to connect non-critical loads to the emergency power system.

Example: In a hospital's intensive care unit (ICU), connecting non-essential equipment to the emergency power system could jeopardize the operation of life-support equipment during an emergency.

Preventing Parallel Operation of Emergency and Normal Power Sources:

Reliable measures must be taken to prevent parallel operation of emergency and normal power sources to maintain the exclusivity of the emergency power supply and prevent backfeeding into the system. This is crucial to ensure the safe and stable operation of the power system.

Example: In complex industrial production environments, improper parallel operation of emergency and normal power sources could lead to short circuits, overloads, or even severe faults, potentially impacting the entire power grid.

Automatic Switching at the Final Distribution Box for Disaster-Prevention Equipment:

Two power supply lines for disaster prevention or similar important electrical equipment should automatically switch at the final distribution box. Large enterprises and significant civil buildings often use several types of emergency power sources, which should work closely together to maximize their effectiveness.

Example: In large commercial complexes, the fire alarm system and fire elevator power lines should automatically switch at the final distribution box to ensure these systems operate reliably in an emergency.

Furthermore, the coordination of various emergency power sources, such as batteries providing short-term backup power, diesel generators for long-term power supply, and UPS systems for instantaneous stability, work together to build a robust and reliable emergency power supply system.