--- title: Protect Your Distributed Power System from Oscillation description: This blog post addresses the concerns designers and engineers face when trying to keep a distributed power system stable. image: https://www.venableinstruments.com/hubfs/Web%20Images/iStock-157336072.jpg --- [![Venable Instruments](https://www.venableinstruments.com/hs-fs/hubfs/VenLogoInst%20%5BConverted%5D-1.png?width=115&height=45&name=VenLogoInst%20%5BConverted%5D-1.png "Venable Instruments")](https://www.venableinstruments.com) Search ## Protect Your Distributed Power System from Oscillation *By Ford Mays - June 25, 2019* # Distributed power systems can oscillate, especially when driving one power supply with another power supply, which could wreak havoc on a system. Thus, keeping a distributed power system operating in a stable manner is one of the main concerns of power system designers and engineers. There are numerous causes for stability issues in distributed power systems, but many are caused by a lack of understanding of source and load impedance interactions. For example, power supplies look like negative resistors at DC. The power supplies’ job is to keep a constant power output over a range of input voltages. Therefore, as the input voltage is increased, the input current decreases. The phase of the power supply tends toward -180° at low frequencies. If the source impedance is resistive, the phases could be 180° different, and oscillation is possible. ![Figure 1 Source and Load with Impdeances](https://www.venableinstruments.com/hs-fs/hubfs/image-2.png?width=730&name=image-2.png) *In this example, the source and load have impedances with the same magnitude of 13mΩ and the phases are opposite around 250 Hz, which means the system will oscillate with just a slight change in DC voltage.* **Avoiding Oscillation Issues** To proactively avoid oscillation issues, test the impedance of each piece of the system using a frequency response analyzer and visually inspect the curves. You can inspect the source and load individually or combine them, but the easiest analysis is to mathematically add the source and load impedances together and inspect the combined impedance. If the combined impedance goes close to zero, you have a problem. If you prefer to inspect the source and load individually, see if the magnitude of the impedances ever come close or cross. If this occurs, look at the phases. If the phases are almost opposite (180° different) you may have a problem. If the magnitudes of the impedances cross when the phases are 180° different, you definitely have a problem. To better understand the causes of oscillation and how to avoid them, download our [*Distributed Power: What Causes These Systems to Oscillate *whitepaper](https://www.venableinstruments.com/hubfs/White%20Papers/Documents%20/Distributed%20Power%20Rev%201.pdf?__hstc=&__hssc=&hsCtaTracking=ba09c31a-becf-4e1b-b896-9a0c990c4fc5%7C51e3fe91-3ef7-4458-a6dc-9d03d0ebc66a).   [![iStock-157336072](https://www.venableinstruments.com/hs-fs/hubfs/Web%20Images/iStock-157336072.jpg?width=1000&name=iStock-157336072.jpg "iStock-157336072")](https://www.venableinstruments.com/lp-distrubuted-power-rev) #### Distributed Power: What Causes These Systems to Oscillate Distributed power systems can oscillate, especially when driving one power supply with another power supply. Download this white paper to learn what causes distributed power systems to oscillate and how you can prevent oscillation. [![Download White Paper](https://hubspot-no-cache-na2-prod.s3.amazonaws.com/cta/default/4867466/c465cf6b-2e2f-4e22-815a-9cfde777e54f.png)](https://hubspot-cta-redirect-na2-prod.s3.amazonaws.com/cta/redirect/4867466/c465cf6b-2e2f-4e22-815a-9cfde777e54f) Comments ### Sign Up for our Blog We promise that we won't SPAM you. #### About Venable Venable provides scalable energy storage and power systems test solutions for precise voltage, current, and frequency measurements, partnering with engineers to ensure battery and power systems around the world will meet stringent field performance demands.  #### Recent news [![Venable Training - Stabilizing Power Supply Control Loops](https://www.venableinstruments.com/hubfs/Venable%20Training%20Front%20Image.jpg) **Venable Training - Stabilizing Power Supply Control Loops** 20 August 2025 ](https://www.venableinstruments.com/blog/stabilizing-power-supply-control-loops) [![The Ins and Outs of System Level Input/Output Impedance Measurements](https://www.venableinstruments.com/hubfs/Imput%20Impedance%20Test%20Set%20UP.jpg) **The Ins and Outs of System Level Input/Output Impedance Measurements** 23 June 2025 ](https://www.venableinstruments.com/blog/impedance-measurements) #### Subscribe Subscribe to our blog to receive emails and updates on scalable power and energy systems test solutions from Venable Instruments.  #### Contact us Venable Instruments 8656 SH 71 West Cuesta Centre, Building E Austin, TX 78735 Office: 512-949-3100 Fax: 512-949-3151