{"id":3566,"date":"2026-10-14T12:33:57","date_gmt":"2026-10-14T04:33:57","guid":{"rendered":"http:\/\/www.apkno.com\/blog\/?p=3566"},"modified":"2026-10-14T12:33:57","modified_gmt":"2026-10-14T04:33:57","slug":"what-are-the-requirements-for-the-operating-temperature-of-a-partial-discharge-sensor-4ff7-5392a3","status":"publish","type":"post","link":"http:\/\/www.apkno.com\/blog\/2026\/10\/14\/what-are-the-requirements-for-the-operating-temperature-of-a-partial-discharge-sensor-4ff7-5392a3\/","title":{"rendered":"What are the requirements for the operating temperature of a partial discharge sensor?"},"content":{"rendered":"

If you\u2019ve ever dealt with partial discharge (PD) testing for power equipment\u2014think transformers, switchgear, or underground cables\u2014you know the sensor is the unsung hero. It\u2019s the thing catching tiny, dangerous electrical leaks before they blow up into full-blown failures. But here\u2019s a question I get every week from engineers and field techs: \u201cWhat operating temp do I actually need for my PD sensor?\u201d I\u2019ve been selling PD test systems and sensors for almost a decade now, and this is the stuff that makes or breaks a project. Skip the generic datasheet fluff\u2014let\u2019s get real about what this actually means for you and your work. Partial Discharge Test System and Sensor<\/a><\/p>\n

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First off, let\u2019s not overcomplicate this. The operating temperature range for a PD sensor isn\u2019t a random number; it\u2019s tied directly to where you\u2019re using it. If you\u2019re testing a transformer in the Arizona desert in July, that\u2019s way different from testing a substation in northern Canada in January. Or, if you\u2019re doing on-site testing in a confined cable manhole that\u2019s been sealed for years and hits 120\u00b0F inside? That\u2019s not the same as calibrating a sensor in a climate-controlled lab.<\/p>\n

Here\u2019s the big rule I drill into every new client: PD sensors have two distinct operating temp zones, and if you mix them up, you\u2019re wasting money (or worse, getting bad data). There\u2019s the \u201cnormal operating range\u201d \u2014 that\u2019s where the sensor is supposed to work as advertised, giving you accurate PD readings every time. Then there\u2019s the \u201cextended survival range\u201d \u2014 that\u2019s the temp it can sit in for a few hours or days without breaking, just not while you\u2019re actually testing. If you run a sensor outside its normal range during testing, your PD readings are garbage, plain and simple. We\u2019ve had clients send sensors back because they tested a transformer at 140\u00b0F and got false positive PD readings, only to realize the sensor\u2019s normal range tops out at 104\u00b0F. Oops.<\/p>\n

Let\u2019s break down the variables that dictate what temp you need. First, on-site vs. lab use. If you\u2019re a maintenance tech doing field testing, your sensor\u2019s normal range needs to cover whatever environment you\u2019re working in. For most general field work, that\u2019s between -20\u00b0C (-4\u00b0F) and 60\u00b0C (140\u00b0F). But wait\u2014if you\u2019re working in remote areas where power equipment is in enclosed spaces, like oil-filled transformer bays that can get super hot because the equipment itself generates heat, you might need that top end pushed to 70\u00b0C (158\u00b0F). I had a client in the Middle East last year testing switchgear in a manhole that hit 85\u00b0C (185\u00b0F) \u2014 his off-the-shelf sensor died mid-test, and he had to wait three days for a replacement. We fixed that for him, but it cost him downtime and a lot of stress.<\/p>\n

Then there\u2019s the type of PD sensor you\u2019re using, because not all sensors are built the same. The two main types we sell are ultrasonic (US) and ultra-high frequency (UHF) \u2014 those are the ones most people use for field testing, right? Ultrasonic sensors work by picking up the sound waves PD emits, usually between 20 and 100 kHz. Their operating temp is limited by the piezoelectric ceramic inside\u2014 that\u2019s the part that converts sound to electrical signals. Piezo ceramics start to lose their sensitivity if it\u2019s too cold, and if it gets too hot, the material can depolarize, meaning it stops working entirely. For our standard ultrasonic sensors, depolarization kicks in around 85\u00b0C (185\u00b0F), so that\u2019s the hard stop for normal operation. Our high-temp ultrasonic sensors are built with a different ceramic that can go up to 120\u00b0C (248\u00b0F), which is perfect for those hot manhole or transformer bay jobs.<\/p>\n

UHF sensors, on the other hand, pick up electromagnetic waves from PD, usually between 300 MHz and 3 GHz. These are used more for indoor substations or GIS (gas-insulated switchgear) because they\u2019re less prone to ambient noise. The big limiting factor for UHF sensors is the antenna and the receiver electronics\u2014 the silicon chips inside don\u2019t like extreme temps. Our standard UHF sensors have a normal range of -10\u00b0C to 55\u00b0C (14\u00b0F to 131\u00b0F), but we have a ruggedized UHF line that goes from -40\u00b0C to 85\u00b0C (-40\u00b0F to 185\u00b0F) for cold-weather work, like testing equipment in the Canadian prairies where winter temps drop to -30\u00b0C (-22\u00b0F). I once had a client in Manitoba tell me his old sensor wouldn\u2019t pick up any PD at -25\u00b0C, and it turned out the receiver chip was failing because it was too cold. The ruggedized ones we sent him fixed that right away.<\/p>\n

Another big one: calibration stability. A PD sensor\u2019s calibration is only good if it\u2019s within its operating temp range. If you test a sensor at 25\u00b0C (77\u00b0F), then use it at 50\u00b0C (122\u00b0F), the sensitivity shifts\u2014usually by 5% to 15%, which might not sound like a lot, but when you\u2019re measuring tiny PD levels that could mean a major failure, that\u2019s a huge margin of error. We always tell clients to check the calibration certificate that comes with their sensor\u2014every reputable PD sensor supplier will list the temp calibration was done at, and how much sensitivity drifts per degree outside the normal range. For example, our standard ultrasonic sensors have a drift of 0.2% per \u00b0C above 60\u00b0C, so if you test at 70\u00b0C, that\u2019s a 2% shift. That\u2019s manageable if you account for it, but if you don\u2019t, you might miss a critical PD signal or flag a false alarm.<\/p>\n

Wait, what about storage? I know, storage isn\u2019t testing, but it matters. If you leave a sensor in a truck bed in the summer, with temps hitting 150\u00b0F, that\u2019s way outside the survival range of even the most rugged sensor. We\u2019ve seen clients leave sensors in their work vans during the summer, and the plastic housing warps, or the wiring inside cracks, which means the next time they use it, it\u2019s faulty. The survival range for most of our sensors is -40\u00b0C to 125\u00b0C (-40\u00b0F to 257\u00b0F), but that\u2019s just for storage\u2014don\u2019t mistake that for testing temp.<\/p>\n

Then there\u2019s the hidden temp factor: self-heating. If your sensor is connected to a power source and running for a long test, it generates a little heat itself. Especially for UHF sensors, which have small amplifiers inside. If you run a 2-hour test on a hot day, the sensor\u2019s internal temp can rise 5 to 10 degrees above the ambient temp outside. I always tell clients to let their sensors acclimate to the environment for at least 30 minutes before testing, and if it\u2019s a long test, don\u2019t leave it strapped to a hot part of the equipment all day\u2014move it around every hour to let it cool a bit. We had a client last year run a 6-hour test on a transformer at 40\u00b0C ambient, and his UHF sensor\u2019s internal temp hit 52\u00b0C, which caused the amplifier to clip the signal\u2014so he got a partial reading instead of a full one. Acclimation fixes that every time.<\/p>\n

What about industrial or offshore use? If you\u2019re testing equipment on an oil rig, or a mining substation, you\u2019re dealing with way worse temps. Offshore, wind speeds can make it feel colder, but the equipment generates so much heat that the ambient temp around the sensor can be 100\u00b0F even if the air temp is 60\u00b0F. For those jobs, we have a line of PD sensors with a normal operating range up to 100\u00b0C (212\u00b0F), built with metal housings and heat-resistant electronics. Mining is another one\u2014underground mines can hit 110\u00b0F, and the dust and humidity make it worse. Those sensors need to not only handle high temps but also be sealed, so temp doesn\u2019t mess with the moisture levels inside the sensor.<\/p>\n

Let\u2019s talk about mistakes I see all the time. One big one: buying a \u201cuniversal\u201d sensor that claims to work in all temps, and then using it in the wrong range. There\u2019s no such thing as a universal PD sensor. Each one is built for a specific range. Another mistake: not accounting for altitude. Wait, how does altitude tie into temp? Oh right, lower pressure at higher altitudes makes equipment run hotter, and the sensor\u2019s ability to dissipate heat is reduced. So if you\u2019re testing a substation in Denver (5,280 ft), a sensor that works great in Houston (sea level) might start to overheat at a lower ambient temp. We actually adjust our sensor specs for altitude, so when you buy from us, we\u2019ll tell you the adjusted operating range for your location.<\/p>\n

Another thing: regulatory standards. If you\u2019re doing PD testing for utilities or industrial clients that follow IEEE or IEC standards, the standards outline specific temp requirements for PD sensors. For example, IEEE 400, which is the standard for field testing of rotating machinery, says the PD sensor must operate within the ambient temp range of the equipment being tested, and sensitivity can\u2019t drift more than 10% over that range. I see clients skip that, and then their test results get rejected because they don\u2019t meet the standard. That\u2019s a big deal\u2014if you\u2019re paying for a PD test and the sensor isn\u2019t up to spec, the whole test is useless.<\/p>\n

So what does this mean for you, right now? If you\u2019re shopping for a PD sensor, first figure out where you\u2019re going to use it 90% of the time. Are you doing field testing in moderate temps, or hot, or cold? Do you need it for indoor GIS or outdoor cables? Check the normal operating temp range vs. the survival range. Ask the supplier about the sensitivity drift outside the normal range\u2014if they can\u2019t give you that number, keep looking. And always ask for a calibration certificate with temp data.<\/p>\n

If you\u2019re already struggling with bad PD readings because of temp? Stop what you\u2019re doing and check your sensor\u2019s spec sheet. Odds are you\u2019re either running it too hot or too cold for testing. We\u2019ve helped dozens of clients fix this\u2014switched out their off-the-shelf sensor for the right one for their environment, walked them through acclimation steps, and they haven\u2019t had a false reading since.<\/p>\n

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At the end of the day, the operating temp requirement for a PD sensor isn\u2019t just a number on a datasheet\u2014it\u2019s the difference between catching a PD fault before it causes a blackout, and missing it, or wasting hours on a test that doesn\u2019t mean anything. We don\u2019t sell one-size-fits-all PD sensors; we build them for your specific job, because we know that temp is the make-or-break factor.<\/p>\n

Partial Discharge Test System and Sensor<\/a> If you\u2019re not sure what sensor you need for your next project, or if you\u2019re having issues with temp-related PD readings, hit us up. We can walk through your work environment, the equipment you\u2019re testing, and help you pick the right sensor that works for your conditions. No generic sales pitches, just straight talk about what will get you accurate, reliable test results.<\/p>\n

References<\/h2>\n
    \n
  1. IEEE Std 400-2012, IEEE Guide for Field Testing and Evaluation of Insulation Systems of Rotating Machinery<\/li>\n
  2. IEC 60270:2015, High-voltage test techniques \u2013 Partial discharge measurements<\/li>\n
  3. NEMA Standards Publication No. C19.100-2018, General Requirements for Electrical Power Apparatus<\/li>\n<\/ol>\n
    \n

    Wuhan Jiuhua Jingce Power Equipment Co., Ltd.<\/a>
    As one of the most experienced partial discharge test system and sensor manufacturers in China, we offer a wide range of products with superior quality. Please feel free to wholesale bulk durable partial discharge test system and sensor from our factory. For price consultation, contact us.
    Address: 601,Unit 1,Building D4-02,Optics Valley Center,303 OpticsValley Avenue,Wuhan
    E-mail: market@wuhanjhjc.com
    WebSite:     https:\/\/www.powertransformertester.com\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

    If you\u2019ve ever dealt with partial discharge (PD) testing for power equipment\u2014think transformers, switchgear, or underground … What are the requirements for the operating temperature of a partial discharge sensor?<\/span>Read more<\/a><\/p>\n","protected":false},"author":417,"featured_media":3566,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[3529],"class_list":["post-3566","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-industry","tag-partial-discharge-test-system-and-sensor-4108-53cd80"],"_links":{"self":[{"href":"http:\/\/www.apkno.com\/blog\/wp-json\/wp\/v2\/posts\/3566","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.apkno.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.apkno.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.apkno.com\/blog\/wp-json\/wp\/v2\/users\/417"}],"replies":[{"embeddable":true,"href":"http:\/\/www.apkno.com\/blog\/wp-json\/wp\/v2\/comments?post=3566"}],"version-history":[{"count":0,"href":"http:\/\/www.apkno.com\/blog\/wp-json\/wp\/v2\/posts\/3566\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.apkno.com\/blog\/wp-json\/wp\/v2\/posts\/3566"}],"wp:attachment":[{"href":"http:\/\/www.apkno.com\/blog\/wp-json\/wp\/v2\/media?parent=3566"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.apkno.com\/blog\/wp-json\/wp\/v2\/categories?post=3566"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.apkno.com\/blog\/wp-json\/wp\/v2\/tags?post=3566"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}