Power Quality in a Tactical Application: What is PQ? Why is it Important?

Issue 91 - May 2019

It is generally accepted that power quality is critical to the reliability and efficiency of operational combat capability. However, relatively little is understood about the relationship and interaction of modern combat capability and the electrical systems they are dependent on. The failure of power and systems engineering to understand this relationship has resulted in increased cost and decreased capability in military systems in general.

In recent years there has been significant R&D investments made in advanced battery chemistries, technologies and renewable energy sources for the warfighter. With the anticipation these new technologies bring, the concern for clean, conditioned power, or “Power Quality”, must remain as part of the discussion. 

What is Power Quality? 

Power Quality can be described as the amount of distortion in voltage, current or frequency from a power source. The power source can be an electrical utility grid, generator or any other energy generating source, on board a ship, on a tactical vehicle, at a radar station, or at a remote deployed operational environment.

The power provided to mission critical systems should be consistently maintained as a clean, conditioned, regulated signal, or sine wave regardless of the state of the power source. The power signal should maintain a constant voltage and frequency with no distortion of the waveform and no interruption of power to the mission critical system (during blackout/brownout). Common power anomalies can include, harmonic distortion, switching transients, line noise, frequency variations, power surges, power sags, high voltage spikes, brownouts and power failures (blackouts).

Benefits of improved power quality include greatly reduced, or eliminated unplanned down time, increased life cycle/Mean Time Between Failure (MTBF) of mission critical systems and cost savings through reduced energy usage and cooling requirements. 

Many Commercial Off the Shelf (COTS) Uninterruptible Power Supplies (UPS) will convert the output signal from a sinewave to a stepped AC wave when operating on battery power as shown in Figure 1. Many times, this output transition will create a switching transient shown in Figure 2. When this transient is supplied to the input of the mission critical system, it will cause damage to the internal components. As this event happens multiple times, it will cause catastrophic equipment failure in the mission critical system, which in turn, will cause unplanned down time for the mission, and at worst case, loss of life for the warfighter or the operational platform. Many of these COTS UPSs are currently deployed in many state of the art defence systems, because the initial cost is very inexpensive. 

Only after there is a catastrophic system failure are these UPSs replaced with ruggedized power conditioners.  

Many military applications use a generator as a power source. It is common that power produced from a generator will have fluctuating frequency and voltage output as seen in Figure 3. Any mission critical system must have a power conditioning element installed between the generator and the mission critical system (load) to correct or regulate any fluctuation or deviation in the power. Many COTS UPSs have a passive filtering circuit that provides very limited conditioning, and only under certain conditions. To properly correct these voltage and frequency fluctuations, and to protect the mission critical system a power conditioner, or UPS with an active filtering circuit must be utilized. 

Many times, a utility power grid will produce line noise, or “dirty power” due to any number of circumstances. Line noise is characterized by “notching” in the waveform when measured with an oscilloscope as shown in Figure 4. This condition is very common in today’s utility grids, because of poor equipment condition, overloading or poor connections, to name a few. Line noise can be especially detrimental to sensitive mission critical systems if not corrected. As described in the previous paragraph, a power conditioner with active filtering is necessary to correct this condition.

Another common power anomaly is harmonics. Harmonics are characterized by a distortion in the voltage, current or frequency waveform as shown in Figure 5. Harmonics are caused by non-linear loads such as switch mode power supplies, variable frequency drives or variable speed drives. These systems can be connected on the system load, or they can be “reflected” from other areas within the electrical distribution network. Active filtering within a power conditioner is required to correct any harmonic distortion.

Another common power anomaly is harmonics. Harmonics are characterized by a distortion in the voltage, current or frequency waveform as shown in Figure 5. Harmonics are caused by non-linear loads such as switch mode power supplies, variable frequency drives or variable speed drives. These systems can be connected on the system load, or they can be “reflected” from other areas within the electrical distribution network. Active filtering within a power conditioner is required to correct any harmonic distortion.

Why is Power Quality Important? 

Clean power quality will ensure that the mission critical system will operate efficiently and will protect the integrity of your data. The net effect of improved power quality is a reduction of maintenance costs and conversely, an increased life cycle of the mission critical systems.

Results of poor power quality are well documented. If the power supply in a mission critical system, for example, is repeatedly exposed to varying degrees of poor power quality, including line noise, transients or harmonic distortion, sensitive components such as transistors and IC chips on circuit boards and power supplies will suffer damage as shown in Figure 6 and Figure 7.  

What can be Done to Improve Power Quality? 

There are many steps that can be taken to improve power quality, chief among them is to install a power conditioner that can isolate, correct and/or mitigate any power quality issues from affecting the mission critical system. Not all power conditioners are created equal. Many times, system engineers may believe all that is required to meet the specifications for an application is a system that can provide battery backup during a loss of input power (UPS). Most COTS UPS systems, however, do not have the active filtering, conditioning and isolation characteristics that are required to meet tough military standards.  

About NOVA Power Solutions

NOVA Power Solutions provides true power quality as part of our equipment capability solution, which provides power conditioning 100% of the time.   NOVA delivers award-winning technical support, customer service, and expert knowledge when providing unsurpassed power protection to mission-critical electronics throughout the world. NOVA Power’s rack-mount rugged and ruggedized uninterruptible power supplies are designed to MIL-STD compliance and well suited to shipboard, tactical military and other harsh operating environments. While NOVA’s power quality solutions are customizable, they include power conditioners, converters, and distribution and battery backup solutions that provide customers a wide-range of power protection and backup alternatives. 

Nova Power Solutions provides true power quality as part of our equipment capability solution, which provides power conditioning 100% of the time. All Nova Power systems are designed with double conversion technology which isolates the load from harmful input harmonics and frequency distortion. Isolation transformers can also be integrated, which will isolate the distribution system from faults and harmonic effects of the load. When input power falls out of tolerance, and the power conditioner/UPS transfers to battery power, Nova Power systems do not create a switching transient on the output from the battery transfer. This will help to increase the life cycle of the mission critical systems. Because Nova Power systems have a more tolerant rectifier input circuit, they will not transfer to battery power during minor input events, or fluctuations. This will increase the life cycle of the batteries within the system. 

Nova Power Solutions offers power condition, conversion, backup and distribution systems. All Nova Power systems are ruggedized and tested to meet various military standards. Nova Power provides custom, scalable solutions to fit a wide range of applications. They are particularly suited for shipboard, tactical military and similar rugged environments. Nova Power has been providing systems for military and heavy industrial applications for over 30 years. With this experience we have a deep understanding of logistics and supply chain management and support the product through its entire life cycle.        

Since 1988 NOVA Power Solutions has been providing shipboard, rack-mount and bulk-head mount uninterruptible power supplies and battery backup modules to the US and allied militaries for use in mission-critical C4I and Combat systems. Additionally, the reliability and ruggedness of our power protection units and battery backup modules, also make it an ideal solution for non-military critical applications like, Urban Security and Public Safety Systems, Intelligent Transportation Systems and Critical Infrastructure Protection Systems.

NOVA Power Difference

NOVA Power Solutions is focused on solving problems encountered during the generation, distribution and use of electrical energy. Recent studies indicate that greater than 80% of electronic systems failures are power supply related. Furthermore, more than 95% of power supply failures are directly or indirectly related to the power quality of the primary electrical system. 

NOVA Power Solutions power conditioning solutions eliminate 98% of distributed electrical system anomalies, increasing system reliability and electrical generation efficiency. 

NOVA Power Solutions power conversion solutions optimize load side electrical efficiency further and thus enhance reliability and allow for the use of a wide spectrum of electronic solutions to meet your requirements. 

NOVA Power has established itself as a premier provider of mission-critical rugged UPS, Power Conditioners, and Battery Backup Modules, with over 40,000 units presently deployed in the world’s harshest environments. Our solutions protect mission critical systems worldwide for applications where “up time” and reliability is absolute and unconditional. 

Süleyman BAYRAMOĞLU NOVA Power Solutions Business Development and Regional Manager for EMEA, says “Based on our more than 30 years of success in the US, since 2013, we have been rather active in Europe, Turkey and the Middle East and have managed to raise awareness of the power quality concept. We have been collaborating with the many defence integrators and manufacturers in the US and Europe, contributing with them in the development of highly reliable defence systems starting from the very bottommost layer. Our mission is to provide reliable power protection solutions to mission-critical electronics throughout the world. We strive to offer our customers industry-leading customer service and peace of mind that they are protected with our high-quality power supplies. To prevent a power failure when it’s not an option, we continue to specialize in customizable, rugged power solutions designed to customer specified requirements and that are particularly suited to shipboard, tactical military and other harsh operating environments.”

NOVA Power is exhibiting at IDEF and the Naval Systems Seminar in October this year, both for the fourth time in a row. BAYRAMOĞLU continues “I must express my satisfaction and appreciation for the emerging opportunities and networking that resulted during previous IDEF shows and other small scale but effective events like the Naval Systems Seminar and the Land Systems Seminar. We consider those events as perfects venues that allow us to explain the importance of power quality in developing high performing and reliable applications to achieve higher operational availability.” 

NOVA Power intends to come together with the engineering teams from system integrators and manufacturers, as well as representatives of the Presidency of Defence Industries, Turkish Army, Navy, Air Force, General Command of the Gendarmerie, Turkish Coast Guard and the Turkish National Police, with a view to inform and raise awareness about the importance of power quality in the development of reliable, high-performing indigenous systems that will enhance the level of operational availability. 

Contribution to Locally Developed Ingenious Systems

The number of systems delivered so far, worldwide exceeds 80.000, while the install base in Turkey is currently around 300. 

Süleyman BAYRAMOĞLU adds, “When we set up our first International office in Turkey in March 2015, we positioned ourselves as ‘Collaborating with prominent defence companies and contributing in their ingenious defence system development activities by providing the most reliable power solutions, thus promoting their ultimate goal of exporting Turkish made state of the art defence systems to regional countries and the world”.  Now we see how right we were when in setting up this objective, and we managed to establish trusted relationships and close collaboration with a number of defence companies, particularly Aselsan, Havelsan and Vestel Defence in developing reliable indigenous defence systems. We are pleased and proud of observing the success of those state-of-the art defence systems designed, developed and integrated by the most talented Turkish engineers in operation”