Industrial Uninterruptible Power Supply

Industrial Uninterruptible Power Supply (UPS) Systems: Design, Equipment, Maintenance

Critical Power Solutions

An uninterruptible power supply system is an essential component for providing reliable backup power to ensure the continuous operation of critical systems during power interruptions. In industrial uninterruptible power systems, downtime can result in costly disruptions, equipment damage, and safety hazards. In municipal and utility environments it ensures reliable performance in municipal services, communications, and critical services. Thus, the design, equipment selection, and maintenance of industrial UPS systems are necessary for achieving maximum reliability and efficiency.

Every UPS system includes the best equipment for the project. What are the best industrial uninterruptible power supply systems equipment manufacturers? A handy reference list published by Meteree offers, "This section provides an overview for uninterruptible power supplies (ups) as well as their applications and principles. Also, please take a look at the list of 67 uninterruptible power supply (ups) manufacturers and their company rankings… as of October, 2024:"¹

This article explores the key aspects of industrial UPS system design, the essential equipment involved, and the recommended maintenance strategies that ensure long-term operational success.

1. Importance of Industrial UPS Systems

In industrial sectors such as manufacturing, energy production, oil and gas, and heavy machinery operations, reliable power is crucial. Additionally, reliable power is mandatory for communications and data centers, healthcare facilities, municipal services (fire, police, ambulance, etc.), utility services, and more. Unexpected power disruptions can lead to:

Downtime: Power outages can halt production, leading to significant financial losses.
Equipment damage: Fluctuations in power can cause equipment failures, leading to costly repairs and replacement.
Safety risks: Power interruptions in environments with dangerous machinery can lead to accidents and harm to workers.
Data loss: In automated industries or those relying on critical IT infrastructure, power interruptions can result in loss of important operational data.

UPS systems provide immediate backup power when the main power source fails, allowing industrial processes to either continue without interruption or shut down safely.

2. Design Considerations for Industrial UPS Systems

The design of an industrial UPS system must account for several critical factors, including power capacity, environmental conditions, and load type. Below are key design considerations:

2.1. Power Capacity and Load Requirements

The first step in UPS system design is determining the power capacity required to support the industrial operation. This is typically expressed in kilovolt-amperes (kVA) or kilowatts (kW). To calculate the required capacity:

Identify critical loads: Determine which devices or systems require continuous power. These can include motors, control systems, safety equipment, and IT infrastructure.
Measure power consumption: Calculate the power consumption (in watts) of each piece of equipment and add them together to determine the total load.
Account for inrush currents: Some industrial equipment, such as motors, can have high inrush currents during startup, which should be accounted for when sizing the UPS system.
Factor in growth: UPS systems should be sized to accommodate future expansion, ensuring that increased power demands don’t require immediate system upgrades.

2.2. UPS Topologies

There are three main types of UPS systems, each offering varying levels of protection. Per the Vertiv website, "The three major types of UPS system configurations are online double conversion, line-interactive and offline (also called standby and battery backup). These UPS systems are defined by how power moves through the unit."². Here are brief descriptions of the three types of UPS system configurations:

Standby (Offline) UPS: This basic design provides power directly from the grid, switching to battery backup in the event of an outage. It offers limited protection against power quality issues like surges or spikes.
Line-Interactive UPS: This type provides more advanced power conditioning, offering protection against voltage sags and surges, while maintaining a connection to the grid. It is often used in industrial environments where power fluctuations are common.
Online Double-Conversion UPS: The most advanced and reliable UPS topology, it continuously converts incoming AC power to DC and then back to AC, providing full isolation from the grid. This design is ideal for sensitive industrial applications that require the highest level of power quality and reliability.

2.3. Environmental Considerations

UPS systems in industrial environments are often exposed to harsh conditions, such as extreme temperatures, dust, humidity, and vibration. The design must account for these factors to ensure long-term performance and reliability:

Temperature control: UPS systems should be placed in climate-controlled environments to prevent overheating and ensure optimal battery performance.
Dust and contamination: Industrial power systems should be installed in clean environments, or in enclosures with appropriate filtering, to prevent damage from dust or other contaminants.
Humidity protection: Humidity can lead to corrosion or short circuits. Therefore, dehumidifiers or sealed enclosures may be necessary in humid industrial settings.

2.4. Battery Selection and Sizing

Batteries are the heart of any UPS system, providing backup power when the main source fails. Key considerations in battery design include:

Battery chemistry: Industrial UPS systems typically use sealed lead-acid (SLA) or lithium-ion batteries. SLA batteries are cost-effective and widely used, while lithium-ion batteries offer longer life cycles, lighter weight, and faster recharge times but come at a higher cost.
Runtime and autonomy: The battery capacity must be sized to provide adequate backup time, allowing either a safe shutdown or continuous operation during power outages. Battery runtime can be extended by adding extra battery banks.
Battery management system (BMS): To ensure optimal performance, industrial UPS systems include BMSs to monitor battery health, state of charge, and overall system status. This helps prevent battery over-discharge, overheating, and capacity degradation.

2.5. Redundancy and Scalability

In industrial environments, redundancy is essential to ensure reliability. Implementing N+1 redundancy—where there is an extra UPS unit that can take over in case of a failure—provides greater system resilience. Scalability is also important, enabling easy upgrades to accommodate increased power needs.

3. Key Equipment in Industrial UPS Systems

UPS systems consist of several critical components that work together to provide reliable power. Key equipment includes:

3.1. Rectifier/Charger

The rectifier/charger is responsible for converting incoming AC power from the grid to DC, which charges the batteries. It also supplies DC power to the inverter.

3.2. Inverter

The inverter converts DC power from the batteries back into AC power, which is used by the connected loads. The inverter ensures that power delivered to equipment is stable and free from fluctuations.

3.3. Battery Bank

The battery bank stores energy for use during power outages. Industrial UPS systems often use large banks of batteries to ensure sufficient backup time for critical loads. Batteries are typically housed in racks or cabinets and monitored by the BMS.

3.4. Static Bypass Switch

The static bypass switch automatically transfers the load from the UPS to the utility power (bypassing the UPS) in case of UPS failure or overload, ensuring uninterrupted power to critical equipment.

3.5. Communication and Monitoring Systems

Industrial UPS systems often integrate advanced communication and monitoring capabilities, allowing operators to remotely monitor system performance, battery health, and environmental conditions. These systems provide real-time data and alert operators to potential issues before they lead to failures.

4. Maintenance Strategies for Industrial UPS Systems

Proper maintenance is critical to ensure the longevity and reliability of industrial uninterruptible power systems. A well-planned maintenance program minimizes the risk of unexpected failures and maximizes system performance. Key maintenance strategies include:

4.1. Regular Inspections

UPS systems should be inspected regularly to identify potential issues early. This includes:

Visual inspection: Check for signs of wear, corrosion, or damage to system components, including cables, battery terminals, and connectors.
Environmental inspection: Ensure that the UPS system is operating within recommended temperature and humidity ranges and that filters are clean and functional.

4.2. Battery Maintenance

Batteries are the most critical and failure-prone component of a UPS system. Proper UPS battery maintenance includes:

Voltage and load testing: Batteries should be tested regularly under load to ensure they can deliver the required power.

Temperature monitoring: Battery life is significantly affected by temperature; batteries should be kept within the manufacturer’s recommended temperature range.
Capacity testing: Over time, battery capacity can degrade. Capacity testing helps determine whether batteries need to be replaced before they fail.
Cleaning and maintenance: Terminals should be kept clean and free from corrosion to ensure proper conductivity.

4.3. Preventive Maintenance

UPS preventive maintenance services involves proactively replacing components before they fail. Preventative maintenance substantially reduces the need for emergency services and costly instances of down-time.

An often overlooked part of UPS system maintenance is compliance with federal Uninterruptible Power Supply Standards. Per the USAID website, "Standards are an invaluable tool in industry and business, because they streamline business practices and provide a level playing field for businesses to develop products and services. They are also critical to ensuring that products and services are safe for consumers and the environment."³. All field services done by AC & DC Power Technologies are done with complete compliance to established requirements.

Preventative maintenance services includes:

Inverter and rectifier maintenance: Key electronic components should be regularly checked and cleaned to prevent failures caused by dust, overheating, or aging.
Firmware updates: UPS systems often come with firmware that controls system operation. Keeping firmware up-to-date ensures the system is operating with the latest improvements and security fixes.

4.4. Emergency Response Plan

Industrial environments require a clear emergency response plan in case of UPS failure. This plan should include:

Replacement parts inventory: Maintain an inventory of critical power and UPS replacement parts, such as batteries, fuses, and circuit boards, for faster response times in cases of components failure.
On-site or remote support: Establish a relationship with a service provider that can offer rapid on-site or remote support in case of system issues or failures.

Conclusion

Industrial uninterruptible power systems are an integral part of maintaining the critical power needs in environments where power interruptions can have significant financial, operational, and safety consequences. Professionally engineered UPS design, equipment selection, and timely maintenance services are crucial for system reliability and longevity of equipment. By investing in a well-designed UPS system and implementing a comprehensive maintenance strategy, industrial operators can significantly reduce the risk of downtime, extend the lifespan of their equipment, and ensure the safety and efficiency of their operations.

For more information on industrial uninterruptible power system design, equipment, field services, or maintenance, call AC & DC Power Technologies at 877-838-9373.

CREDITS and FOOTNOTES

¹ Staff Writer, "67 Uninterruptible Power Supply (UPS) Manufacturers in 2024", October 31, 2024 Available from Metoree
² Staff Writer, "What Are the Different Types of UPS Systems?", April 20, 2024, Available from Vertiv
³ Staff Writer, "Uninterruptible Power Supply Standards", January 21, 2019, Available from USAID
Photo by Public Domain Pictures, available at Pixabay