{"id":3516,"date":"2026-10-14T11:36:19","date_gmt":"2026-10-14T03:36:19","guid":{"rendered":"http:\/\/www.thienphucons.com\/blog\/?p=3516"},"modified":"2026-10-14T11:36:19","modified_gmt":"2026-10-14T03:36:19","slug":"how-to-use-fmea-to-improve-the-design-of-high-voltage-capacitors-4e35-3df7e0","status":"publish","type":"post","link":"http:\/\/www.thienphucons.com\/blog\/2026\/10\/14\/how-to-use-fmea-to-improve-the-design-of-high-voltage-capacitors-4e35-3df7e0\/","title":{"rendered":"How to use FMEA to improve the design of high – voltage capacitors?"},"content":{"rendered":"

Hey everyone, it\u2019s Jake from the high-voltage capacitor team here, and today I want to cut through the corporate jargon to talk about something we actually swear by at my shop: FMEA for designing better high-voltage caps. If you\u2019re in the energy, industrial automation, or grid upgrade game, you know how critical these caps are\u2014mess up their design, and you\u2019re looking at downtime, safety risks, or even costly failures that tank projects. That\u2019s where FMEA comes in, and no, it\u2019s not just another acronym we throw around in meetings; it\u2019s how we\u2019ve fixed half the issues our clients used to complain about, one step at a time. High-voltage Capacitor<\/a><\/p>\n

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First off, let\u2019s get the obvious out of the way: FMEA stands for Failure Mode and Effects Analysis. For the uninitiated, it\u2019s this systematic process where we map out every single way a part, process, or system could fail, figure out why that happens, how likely it is, how bad the fallout is, and what we can do to prevent or catch it before it leaves our facility. When it comes to high-voltage capacitors, this isn\u2019t trivial\u2014these things are handling kilovolts, so a failure isn\u2019t just a minor inconvenience. We\u2019re talking about arcing, thermal runaway, even safety hazards that could shut down a substation or a manufacturing line for days. So FMEA isn\u2019t just a nice-to-have here; it\u2019s non-negotiable for us as a supplier.<\/p>\n

Let me walk you through how we actually apply this at our shop, because I don\u2019t want to just rattle off definitions. We start with the design phase, way before we ever put ink on manufacturing blueprints, because fixing a flaw in the drawing is way cheaper than fixing a failed cap in the field (trust me, we\u2019ve learned that lesson the hard way). First, we bring together a cross-functional team\u2014our design engineers, the production guys who build the caps, the quality team that tests them, and even a few reps from our client-facing side who hear complaints firsthand. No silos here; everyone\u2019s input counts. For example, last year a utility client mentioned they were seeing weird failures in outdoor high-voltage caps during extreme heat. So we pulled those sales reps into our next FMEA huddle.<\/p>\n

The first step in our FMEA workflow for HV caps is to define the system clearly. What exactly are we designing? Is this a cap for a grid-tied inverter? A transformer bank? A renewable energy storage unit? Each use case has different stressors. Let\u2019s say we\u2019re designing a 12kV metallized polypropylene cap for a solar inverter. Right out the gate, our team starts listing every possible failure mode. This isn\u2019t a quick brain dump\u2014we break down the cap into its core components: the dielectric material (polypropylene film), the metallized electrodes, the winding structure, the encapsulation resin, the terminals, and even the connection points to the circuit.<\/p>\n

For each component, we ask: \u201cHow could this fail?\u201d Let\u2019s take the dielectric film first. Common failure modes here are things like dielectric breakdown (where the insulation breaks down under voltage), partial discharge (PD, tiny sparks that eat away at the film over time), or delamination of the film layers. Next, we analyze the effects of each failure. For dielectric breakdown, the immediate effect is a short circuit in the cap, which could blow the inverter\u2019s fuse or cause overcurrent. The end effect? If that happens in a remote solar farm, you\u2019re looking at days of downtime, lost energy production, and potentially damage to the inverter itself. For partial discharge, the effect is slower\u2014gradual erosion of the dielectric leading to eventual breakdown, so the cap lasts way less than its 10-year warranty.<\/p>\n

Then comes the risk priority number (RPN), which is Severity (S) times Occurrence (O) times Detection (D). We rate each on a 1-10 scale, 10 being worst. For dielectric breakdown in a solar inverter, Severity is a 9\u2014can take down a whole string of panels. Occurrence was a 7 for our old design; we were seeing that issue about 7 out of 100 units under full load. Detection was a 5, because our in-line testing missed a few latent defects. So RPN was 97<\/em>5=315, which is way too high for us. That\u2019s the red flag we needed to fix things.<\/p>\n

Now, here\u2019s where FMEA actually drives action, not just data collection. We brainstorm mitigation strategies to bring down the RPN. For that dielectric breakdown issue, we looked at two things first: O and D. To lower Occurrence, we switched from standard biaxially oriented polypropylene (BOPP) film to a thicker, cross-laminated film with a self-healing coating. Wait, what\u2019s self-healing? Basically, if a tiny spark does start, the metal electrode around that spark vaporizes, cutting off the fault before it can spread. We tested that, and Occurrence dropped to 2\u2014super rare. Then, for Detection, we added a post-winding partial discharge test that\u2019s way more sensitive than our old method, so we can catch any latent film defects before the cap leaves our shop. That bumped Detection down to 2. Now the RPN is 92<\/em>2=36, which is almost unheard of for this type of cap. That\u2019s the kind of win we live for.<\/p>\n

But FMEA isn\u2019t a one-and-done thing. We do it at every stage of the design, not just the initial drawing board. When we\u2019re prototyping, we do a mini-FMEA to test the new design in our lab. Last quarter, we were testing a new winding structure where we stacked more film layers to get higher capacitance in a smaller size. The failure mode we caught early was \u201clayer misalignment\u201d during winding, which could cause hotspots. Our Occurrence was 6, Severity 8, Detection 4\u2014RPN 192. The fix? We added a laser-guided winding machine that holds each layer perfectly aligned, and a vision system that checks alignment mid-wind. That dropped Occurrence to 1, so now that design is solid.<\/p>\n

We also update our FMEA whenever we get field feedback. A few months ago, a client in a coastal area called with caps that were failing faster than expected. Turns out the encapsulation resin we were using wasn\u2019t resistant to salt spray and high humidity, so water was seeping in and causing corrosion on the terminals. We pulled that into our FMEA as a new failure mode: \u201cencapsulation degradation due to environmental exposure.\u201d Severity was 8, Occurrence was 5 (since coastal environments are common for grid projects), Detection was 3 (we didn\u2019t test for salt spray enough). Mitigation? We switched to a epoxy resin with a UV and corrosion-resistant top coat, and added a 1000-hour salt spray test to our production line. Now that client\u2019s failures are gone, and we\u2019ve added that to our FMEA for all outdoor-rated HV caps, not just coastal ones.<\/p>\n

Another big thing with high-voltage caps is thermal management. Heat is the enemy of every HV component, and caps are no exception. Overheating reduces the dielectric\u2019s lifespan, makes the metal electrodes degrade faster, and can lead to thermal runaway\u2014super dangerous because that can cause the cap to explode. So in our FMEA, \u201coverheating due to poor thermal dissipation\u201d is a top-level failure mode. Let\u2019s break that down: Occurrence for our old design was 4, because we were using a standard aluminum casing. Severity was 9, because thermal runaway is a safety hazard, Detection was 5 (we only tested surface temp at full load, not internal). The fix? We switched to a cast aluminum casing with integrated heat sinks, and added embedded thermocouples that monitor internal temperature in real time. Now Occurrence is 1, Detection is 1, RPN drops from 180 to 9. That\u2019s not just better for the client; it\u2019s better for everyone on site if something goes wrong.<\/p>\n

I should also mention that FMEA isn\u2019t just for new designs\u2014we use it for continuous improvement on existing products too. Last year, we had a batch of medium-voltage caps that were failing due to loose terminal connections. We pulled the FMEA for that model, saw that the assembly step had a failure mode \u201cterminal crimp insufficient torque,\u201d Occurrence 5, Severity 7, Detection 4. We retrained our production team on crimp torque specs, added a torque wrench with digital verification, and now Occurrence is down to 1. No more loose terminals, no more client complaints, and way less rework on our end.<\/p>\n

At the end of the day, what FMEA does for us as a capacitor supplier is take the guesswork out of design. We\u2019re not just building parts that meet basic specs; we\u2019re building parts that actually perform in real-world conditions, whether that\u2019s a solar farm in Arizona\u2019s 110\u00b0F heat, a substation in Alaska\u2019s -40\u00b0F cold, or a wind farm off the coast of Florida. We don\u2019t cut corners on testing, because FMEA forces us to ask \u201cwhat if\u201d before a failure happens, not after.<\/p>\n

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If you\u2019re here because you\u2019re having issues with your current HV capacitors\u2014maybe they\u2019re not lasting as long as they should, failing unexpectedly, or you\u2019re looking for a supplier that actually stands behind their design choices\u2014we\u2019re here to help. Our team uses FMEA on every single one of our capacitor models, and we\u2019re always willing to walk through how we\u2019ve fixed similar issues for other clients. Whether you need a custom design for a specific application, or you just want to chat about improving the reliability of your HV system, reach out to our sales team to connect for a consultation. We don\u2019t do generic one-size-fits-all caps, and we don\u2019t do design guesswork\u2014we do FMEA-backed designs that work when you need them to.<\/p>\n

High-voltage Capacitor<\/a> References<\/p>\n

    \n
  1. Stamatis, D. H. Failure Mode and Effect Analysis: FMEA from Theory to Execution, 2nd Edition. ASQ Quality Press, 2003.<\/li>\n
  2. IEC 60831-1:2014, Shunt power capacitors for AC systems of 1 kV and above \u2013 Part 1: General specifications, performance requirements, testing and rating. International Electrotechnical Commission, 2014.<\/li>\n
  3. Vardell, T. J., and Gopalarathnam, R. \u201cPartial Discharge in Metallized Polypropylene Capacitors for Renewable Energy Applications.\u201d IEEE Transactions on Dielectrics and Electrical Insulation, vol. 22, no. 3, 2015, pp. 1486\u20131492.<\/li>\n
  4. Kundur, P. Power System Stability and Control, 2nd Edition. McGraw-Hill, 2019.<\/li>\n<\/ol>\n
    \n

    Jiangyin Furida High-Voltage Ceramic Capacitor Co., Ltd.<\/a>
    As one of the leading high-voltage capacitor manufacturers and suppliers in China, we warmly welcome you to purchase high-value high-voltage capacitor made in China here from our factory. All customized products are with high quality and competitive price.
    Address: No. 154, Hutang Street, Xuxiake Town, Jiangyin City, Wuxi, Jiangsu Province
    E-mail: 13771223028@qq.com
    WebSite:     https:\/\/www.jyfurita.com\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

    Hey everyone, it\u2019s Jake from the high-voltage capacitor team here, and today I want to cut … How to use FMEA to improve the design of high – voltage capacitors?<\/span>Read more<\/a><\/p>\n","protected":false},"author":288,"featured_media":3516,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[3479],"class_list":["post-3516","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-industry","tag-high-voltage-capacitor-4b42-3e2861"],"_links":{"self":[{"href":"http:\/\/www.thienphucons.com\/blog\/wp-json\/wp\/v2\/posts\/3516","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.thienphucons.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.thienphucons.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.thienphucons.com\/blog\/wp-json\/wp\/v2\/users\/288"}],"replies":[{"embeddable":true,"href":"http:\/\/www.thienphucons.com\/blog\/wp-json\/wp\/v2\/comments?post=3516"}],"version-history":[{"count":0,"href":"http:\/\/www.thienphucons.com\/blog\/wp-json\/wp\/v2\/posts\/3516\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.thienphucons.com\/blog\/wp-json\/wp\/v2\/posts\/3516"}],"wp:attachment":[{"href":"http:\/\/www.thienphucons.com\/blog\/wp-json\/wp\/v2\/media?parent=3516"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.thienphucons.com\/blog\/wp-json\/wp\/v2\/categories?post=3516"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.thienphucons.com\/blog\/wp-json\/wp\/v2\/tags?post=3516"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}