In high-amperage applications, the effective filtering of high-frequency noise is critical to ensure optimal performance and reliability of electronic systems. This is particularly important in long-range protection measures against High-Altitude Electromagnetic Pulse (HEMP) events and other excess current scenarios.

Often multiple filters of lower amperage are deployed to operate in a system of higher rating. However, installation of multiple filters in parallel presents a set of side effects that may disrupt system performance. Some of the risks associated with parallel filter configuration in HEMP mitigation may include:

Impedance Mismatch

One of the primary challenges when installing multiple high-frequency filters in parallel is impedance mismatch. Each filter has its inherent impedance characteristics, which can vary based on the design, components, and operating frequency range. When filters with mismatched impedances are connected in parallel, it can lead to unwanted interactions, reflections, and resonances. These phenomena can result in compromised filtering efficiency, distortion of signals, and even the introduction of additional noise into the system.

Resonance and Oscillations

Parallel installation of high-frequency filters can create resonant circuits and oscillations, particularly when the filters exhibit resonant behavior at similar frequencies. Resonance occurs when the combined impedance of the filters and the system forms a low-impedance path at a specific frequency. This can lead to amplified noise signals and even damage to the filters or other components. Oscillations, on the other hand, result from positive feedback loops caused by the interaction of multiple filters, further exacerbating the problem.

Current Division and Overloading

Parallel installation of filters can introduce challenges in current division among the filters. When filters are connected in parallel, the current distribution may not be uniform due to variations in impedance characteristics and the impedance of the source. This non-uniform current distribution can result in overloading of some filters while leaving others underutilized. Overloaded filters may experience increased heat dissipation, reduced lifespan, and potentially compromised filtering performance, while underutilized filters may not operate at their optimal efficiency.

Interference and Crosstalk

Parallel installation of high-frequency filters can lead to interference and crosstalk issues. Filters are designed to suppress specific frequency ranges, and their proximity in a parallel arrangement can create interference between them. This interference can cause unintended coupling of signals, resulting in crosstalk and distortion. Additionally, the introduction of multiple filters can create complex electromagnetic interactions, which may further impact neighboring components and subsystems.

Complexity and Cost

Installing multiple high-frequency filters in parallel increases system complexity and cost. Each additional filter adds complexity to the design, installation, and maintenance processes. Moreover, the need for additional components, cabling, and interconnections raises costs associated with material, manufacturing, and testing. The increased complexity can also lead to challenges in troubleshooting, identifying faults, and ensuring system-wide compatibility.

Compliance Issues

Linking filters in parallel may be offered by contractors as a solution in high-amperage applications, but the design scheme fails to meet best practices according to military standards. This type of arrangement can let residual current through that can exceed limits established by the Defense Threat Reduction Agency (DTRA). Many critical infrastructure projects in the civilian sector follow Department of Defense (DoD) standards and guidance for HEMP protection.

New 5000-AMP Filters

The alternative design strategy would be to use a single, higher-rated filter. Fortunately, larger capacity certified filters have recently come to market. TSS USA Manufacturing introduced the first-of-its-kind HEMP filter is available in ratings up to 5000 AMP in a single unit, far surpassing competing products, which are generally have an upper limit of 1200 AMP.

A single high-frequency filter avoids the potential unwanted electrical phenomena that can result with multiple 1200 AMP filters in parallel, as outlined above. In practice, parallel configuration in high-amperage systems lead to hot spots and early failure.

Additionally, TSS USA Manufacturing guarantees their filters meet MIL-STD-188-125-1A compliance when integrated into a client’s system. Many competitors cannot make the same promise.

Find out which TSS USA filters fit your particular system requirements.