{"id":6387,"date":"2026-03-27T16:30:39","date_gmt":"2026-03-27T08:30:39","guid":{"rendered":"https:\/\/kvhipot.com\/?p=6387"},"modified":"2026-03-27T16:32:42","modified_gmt":"2026-03-27T08:32:42","slug":"jaka-je-zkusebni-napeti-pro-testovani-strednich-napetich-kabelu-podle-norem-sec","status":"publish","type":"post","link":"https:\/\/kvhipot.com\/cs\/what-is-the-test-voltage-for-middle-voltage-cable-testing-as-per-sec-standards\/","title":{"rendered":"Jak\u00e1 je zku\u0161ebn\u00ed nap\u011bt\u00ed pro testov\u00e1n\u00ed kabel\u016f st\u0159edn\u00ed nap\u011bt\u00ed podle standard\u016f SEC?"},"content":{"rendered":"

<\/p>

V bezohledn\u00e9 pou\u0161ti m\u016f\u017ee v\u00fdpadek proudu \u00fapln\u011b zastavit ve\u0161kerou \u010dinnost.<\/p>

Elektrick\u00e1 infrastruktura Sa\u00fadsk\u00e9 Ar\u00e1bie je siln\u011b z\u00e1visl\u00e1 na rozvodn\u00e9 s\u00edti s nap\u011bt\u00edm st\u0159edn\u00edho nap\u011bt\u00ed, kter\u00e1 je zalo\u017eena na okruz\u00edch o nap\u011bt\u00ed 13,8 kV a 33 kV. Tyto nap\u011b\u0165ov\u00e9 \u00farovn\u011b zaji\u0161\u0165uj\u00ed ide\u00e1ln\u00ed rovnov\u00e1hu mezi kapacitou nap\u00e1jen\u00ed a \u00fa\u010dinnost\u00ed p\u0159enosu, co\u017e napojuje rozvodn\u00e9 stanice, pr\u016fmyslov\u00e9 parky a cel\u00e9 m\u011bstsk\u00e9 oblasti. Stabiln\u00ed dod\u00e1vka je kl\u00ed\u010dov\u00e1 pro podporu rafineri\u00ed, datov\u00fdch center a rozs\u00e1hl\u00e9 infrastruktury.<\/p>

Na rozd\u00edl od mnoha dal\u0161\u00edch region\u016f \u010del\u00ed Sa\u00fadsk\u00e1 Ar\u00e1bie unik\u00e1tn\u00edm environment\u00e1ln\u00edm probl\u00e9m\u016fm: prudk\u00e9mu n\u00e1r\u016fstu teplot do 50 \u00b0C, trval\u00e9mu pronik\u00e1n\u00ed p\u00edsku a vysok\u00e9 vlhkosti pob\u0159e\u017e\u00ed. V t\u011bchto extr\u00e9mn\u00edch podm\u00ednk\u00e1ch se stres zp\u016fsoben\u00fd izolac\u00ed v\u00fdrazn\u011b zvy\u0161uje. V d\u016fsledku toho spole\u010dnost Saudi Electricity Company (SEC) implementuje p\u0159\u00edsn\u00e9 testovac\u00ed postupy, aby zajistila, \u017ee ka\u017ed\u00fd instalovan\u00fd kabel z polyethylenu s p\u0159\u00edmou s\u00edt\u00ed (XLPE) nebo pry\u017eov\u00e9 gumy z ethylenu a propylenu (EPR) bude schopn\u00fd vydr\u017eet o\u010dek\u00e1van\u00e9 provozn\u00ed zat\u00ed\u017een\u00ed.<\/p>

\"\"<\/figure>

Obvykle dod\u00e1vaj\u00ed p\u0159\u00edvodn\u00ed veden\u00ed 13,8 kV m\u011bstsk\u00e9 s\u00edt\u011b a men\u0161\u00ed pr\u016fmyslov\u00e9 u\u017eivatele, zat\u00edmco okruhy o nap\u011bt\u00ed 33 kV zaji\u0161\u0165uj\u00ed prim\u00e1rn\u00ed distribuci do centr\u00e1ln\u00edch rozvodn\u00fdch stanic a hlavn\u00edch pr\u016fmyslov\u00fdch za\u0159\u00edzen\u00ed. P\u0159ed zprovozn\u011bn\u00edm mus\u00ed ka\u017ed\u00fd kabelov\u00fd \u00fasek podstoupit testy k ov\u011b\u0159en\u00ed integrity svazk\u016f a konektor\u016f. Zpr\u00e1va SEC o spolehlivosti z roku 2023 uv\u00e1d\u00ed, \u017ee t\u00e9m\u011b\u0159 70% poruch p\u0159\u00edvodn\u00edch veden\u00ed s vysok\u00fdm nap\u011bt\u00edm lze p\u0159i\u010d\u00edst vad\u00e1m p\u0159i mont\u00e1\u017ei. Tato statistika p\u0159esn\u011b poukazuje na to, pro\u010d je standardizovan\u00e9 testov\u00e1n\u00ed s velmi n\u00edzkou frekvenc\u00ed (VLF) povinn\u00e9 pro ka\u017edou novou nebo obnovenou rozvodnou soustavu.<\/p>

Nakonec z\u00e1vis\u00ed spolehlivost nap\u00e1jen\u00ed a bezpe\u010dnost syst\u00e9mu na d\u016fsledn\u00e9m testov\u00e1n\u00ed t\u011bchto kabel\u016f p\u0159ed jejich zprovozn\u011bn\u00edm.<\/p>

\u00darove\u0148 nap\u011bt\u00ed<\/strong><\/strong><\/td>Obor pou\u017eit\u00ed<\/strong><\/strong><\/td>Typ kabelu<\/strong><\/strong><\/td>Typick\u00e1 role v okruhu<\/strong><\/strong><\/td>Obecn\u00fd typ testu<\/strong><\/strong><\/td><\/tr>
13,8 kV<\/td>M\u011bstsk\u00e9 p\u0159enosov\u00e9 veden\u00ed, rozvodn\u00ed stanice<\/td>XLPE<\/td>Odch\u00e1zej\u00edc\u00ed p\u0159\u00edvodn\u00ed okruhy<\/td>Test sinusov\u00fdch vln VLF s frekvenc\u00ed 0,1 Hz<\/td><\/tr>
33 kV<\/td>Subtransmisie, velk\u00e1 spot\u0159ebitelsk\u00e1 popt\u00e1vka<\/td>XLPE<\/td>P\u0159\u00edvod z hlavn\u00ed rozvodny<\/td>Test odolnosti v\u016f\u010di VLF<\/td><\/tr><\/tbody><\/table><\/figure>

Normy pro testov\u00e1n\u00ed kabel\u016f s st\u0159edn\u00edm nap\u011bt\u00edm: <\/strong><\/h2>

Srovn\u00e1n\u00ed po\u017eadavk\u016f SEC s IEC 60502-2 (2024) a IEEE 400.2<\/strong><\/p>

Dodavatel\u00e9 EPC \u010dasto maj\u00ed pot\u00ed\u017ee sladit m\u00edstn\u00ed po\u017eadavky sa\u00fadskoarabsk\u00e9 elektrick\u00e9 spole\u010dnosti (SEC) s mezin\u00e1rodn\u00edmi normami, co\u017e vede k nejistot\u011b p\u0159i v\u00fdb\u011bru \u00farovn\u00ed zku\u0161ebn\u00e9ho nap\u011bt\u00ed. Ve skute\u010dnosti odpov\u00edd\u00e1 zku\u0161ebn\u00ed z\u00e1t\u011b\u017e nap\u011bt\u00ed izolace SEC t\u011bsn\u011b sm\u011brnic\u00edm Very Low Frequency (VLF) uveden\u00fdm v IEEE 400.2:2023 a IEC 60502-2:2024. Oba tyto mezin\u00e1rodn\u00ed dokumenty definuj\u00ed po\u017eadovan\u00e9 zku\u0161ebn\u00e9 nap\u011bt\u00ed jako 3U\u2080 RMS (kde U\u2080 je nap\u011bt\u00ed kabelov\u00e9ho syst\u00e9mu v f\u00e1zi k zemi). Nav\u00edc kv\u016fli riziku hromad\u011bn\u00ed prostorov\u00e9ho n\u00e1boje IEC v\u00fdslovn\u011b nedoporu\u010duje DC zku\u0161ebn\u00ed metody pro kabelov\u00e9 syst\u00e9my s v\u00edcevrstvou polyethylenovou izolac\u00ed (XLPE), a m\u00edsto toho doporu\u010duje sinus\u00e1ln\u00ed metodu VLF.<\/p>

Zdroj Standard<\/strong><\/strong><\/td>Doporu\u010den\u00fd nap\u011bt\u00ed<\/strong><\/strong><\/td>Podstata (U\u2080)<\/strong><\/strong><\/td>D\u00e9lka testu<\/strong><\/strong><\/td>Typ frekvence<\/strong><\/strong><\/td><\/tr>
IEC 60502-2 (2024)<\/td>3 \u00d7 U\u2080<\/td>F\u00e1zov\u00e1 k zemi nap\u011bt\u00ed<\/td>15\u201360 minut<\/td>Sine s frekvenc\u00ed 0,1 Hz<\/td><\/tr>
IEEE 400.2<\/td>3 \u00d7 U\u2080<\/td>F\u00e1zov\u00e1 k zemi nap\u011bt\u00ed<\/td>15\u201360 minut<\/td>Sine s frekvenc\u00ed 0,1 Hz<\/td><\/tr>
Pr\u016fvodce SEC (2022)<\/td>Stejn\u00e9 jako IEC<\/td>8 kV (13,8 kV) \/ 19 kV (33 kV)<\/td>Typick\u00e9 30 minut<\/td>Sine s frekvenc\u00ed 0,1 Hz<\/td><\/tr><\/tbody><\/table><\/figure>

Vzhledem k tomu, \u017ee v\u011bt\u0161ina sa\u00fadsk\u00fdch projekt\u016f vyu\u017e\u00edv\u00e1 postupy SEC (kter\u00e9 odr\u00e1\u017eej\u00ed standardy IEEE a IEC), je pro in\u017een\u00fdry kl\u00ed\u010dov\u00fdm praktick\u00fdm krokem ov\u011b\u0159it v\u00fdstupn\u00ed v\u00fdstup jejich testovac\u00edho za\u0159\u00edzen\u00ed. Je nezbytn\u00e9 ov\u011b\u0159it, zda tester zobrazuje nap\u011bt\u00ed ve st\u0159edn\u00ed hodnot\u011b (RMS) nebo \u0161pi\u010dkov\u00e9 nap\u011bt\u00ed, aby bylo zaji\u0161t\u011bno spr\u00e1vn\u00e9 p\u016fsoben\u00ed zat\u00ed\u017een\u00ed.<\/p>

SEC sv\u00e9 po\u017eadavky p\u0159\u00edmo vych\u00e1z\u00ed z normy IEEE 400.2 a aktualizace normy IEC 60502-2 z roku 2024. Ob\u011b normy se shoduj\u00ed na stejn\u00e9 z\u00e1kladn\u00ed metodice: prov\u00e1d\u011bn\u00ed test\u016f VLF s frekvenc\u00ed 0,1 Hz na nov\u00fdch a opraven\u00fdch kabel\u00edch pomoc\u00ed sinusov\u00e9 vlny s RMS nap\u011bt\u00edm 3U\u2080. Norma IEEE 400.2 (2023) kategorizuje testy do kategori\u00ed instalace, akceptace a \u00fadr\u017eby. <\/p>

Pro mont\u00e1\u017e a zkou\u0161ku XLPE kabel\u016f je stanovena RMS nap\u011bt\u00ed 3U\u2080, kter\u00e9 se mus\u00ed aplikovat po dobu od 15 do 60 minut. IEC 60502-2 (2024) toto nap\u011bt\u00ed posiluje a znovu zd\u016fraz\u0148uje opat\u0159en\u00ed proti testov\u00e1n\u00ed stejnosm\u011brn\u00fdm proudem, p\u0159i\u010dem\u017e uv\u00e1d\u00ed, \u017ee uzav\u0159en\u00e9 elektrostatick\u00e9 pole m\u016f\u017ee v\u00fdrazn\u011b zkr\u00e1tit \u017eivotnost izolace.<\/p>

\"\"
Vysokonap\u011b\u0165ov\u00fd elektrick\u00fd kabel je polo\u017een v p\u0159\u00edkopu.<\/figcaption><\/figure>

SEC tyto pokyny kodifikovala ve sv\u00e9m dokumentu 33-TMSS-09, kter\u00fd stanov\u00ed 30minutov\u00fd test odolnosti nap\u011bt\u00ed 3U\u2080 RMS pro v\u0161echny kablov\u00e9 \u010d\u00e1sti s nap\u011bt\u00edm 13,8 kV nebo 33 kV. Tato konkr\u00e9tn\u00ed nap\u011b\u0165ov\u00e1 \u00farove\u0148 p\u016fsob\u00ed na izolaci tlakem p\u0159ibli\u017en\u011b 2,5 a\u017e 3kr\u00e1t vy\u0161\u0161\u00edm ne\u017e b\u011b\u017en\u00e9 provozn\u00ed zat\u00ed\u017een\u00ed. Testov\u00e1n\u00ed pod touto prahovou hodnotou by mohlo v\u00e9st k nepravdiv\u00e9mu \u201cp\u0159i\u0159azen\u00ed\u201d jako \u201ep\u0159i spr\u00e1vn\u00e9m stavu\u201c, co\u017e by nepozorovalo latentn\u00ed dielektrick\u00e9 vady nebo slabiny spojen\u00e9 s st\u00e1rnut\u00edm.<\/p>

Hlavn\u00ed v\u00fdhodou testov\u00e1n\u00ed sinusov\u00fdch vln VLF je jej\u00ed schopnost simulovat nap\u011bt\u00ed elektrick\u00e9ho pole p\u0159i frekvenci nap\u00e1jen\u00ed stejnosm\u011brn\u00e9ho proudu, p\u0159i\u010dem\u017e vy\u017eaduje v\u00fdrazn\u011b men\u0161\u00ed v\u00fdkon. Nav\u00edc, pokud je za\u0159\u00edzen\u00ed k tomu vybaveno, sinusov\u00e1 vlnov\u00e1 frekvence VLF umo\u017e\u0148uje provozovatel\u016fm prov\u00e1d\u011bt p\u0159esn\u011bj\u0161\u00ed m\u011b\u0159en\u00ed \u010d\u00e1ste\u010dn\u00e9ho v\u00fdboje (PD). Tato kombinace efektivn\u00edho testov\u00e1n\u00ed izolace p\u0159i vysok\u00e9m nap\u011bt\u00ed a n\u00edzk\u00e9 spot\u0159eby energie z n\u00ed \u010din\u00ed VLF celosv\u011btov\u00fdm standardem pro p\u0159ij\u00edm\u00e1n\u00ed kabel\u016f st\u0159edn\u00edho nap\u011bt\u00ed.<\/p>

Jak vypo\u010d\u00edtat spr\u00e1vnou injek\u010dn\u00ed nap\u011bt\u00ed pro kabely z polyethylenu s p\u0159\u00edm\u00fdm a zk\u0159\u00ed\u017een\u00fdm vl\u00e1knem o nap\u011bt\u00ed 13,8 kV a 33 kV, Pou\u017e\u00edv\u00e1te VLF tester?<\/strong><\/h2>

Formulace je n\u00e1sleduj\u00edc\u00ed. Z\u00e1kladn\u00edm p\u0159edpokladem p\u0159esn\u00e9ho testov\u00e1n\u00ed VLF je rozli\u0161ov\u00e1n\u00ed mezi jmenovit\u00fdm nap\u011bt\u00edm U mezi linkami syst\u00e9mu a nap\u011bt\u00edm U\u2080 mezi f\u00e1zemi a zem\u00ed. Standardy jako IEEE 400.2 vych\u00e1zej\u00ed z po\u017eadavk\u016f na odolnost p\u0159i zkou\u0161ce pomoc\u00ed opakov\u00e1n\u00ed hodnoty U\u2080.<\/p>

\"\"<\/figure>

Nespr\u00e1vn\u00e9 vkl\u00e1d\u00e1n\u00ed nap\u011bt\u00ed je jednou z nej\u010dast\u011bj\u0161\u00edch chyb p\u0159i ter\u00e9nn\u00edch testech, zejm\u00e9na kdy\u017e m\u011b\u0159ic\u00ed p\u0159\u00edstroj VLF zobrazuje maxim\u00e1ln\u00ed hodnoty, ale in\u017een\u00fd\u0159i p\u0159edpokl\u00e1daj\u00ed hodnotu RMS.
Pro v\u00fdpo\u010det spr\u00e1vn\u00e9ho zku\u0161ebn\u00edho nap\u011bt\u00ed plat\u00ed jednoduch\u00fd vzorec:
RMS \u00d7 1,414 = vrcholov\u00fd v\u00fdstup.<\/strong>
U\u2080 pro kabel o nap\u011bt\u00ed 13,8 kV \u010din\u00ed p\u0159ibli\u017en\u011b 8 kV, tak\u017ee 3U\u2080 = 24 kV RMS (peak 34 kV).
U\u2080 pro kabel o nap\u011bt\u00ed 33 kV je p\u0159ibli\u017en\u011b 19 kV, tak\u017ee 3U\u2080 = 57 kV RMS (81 kV p\u0159i maxim\u00e1ln\u00edm nap\u011bt\u00ed).<\/p>

Klasifikace kabelu<\/strong><\/strong><\/td>U0 (f\u00e1zov\u00e1\u2013zemn\u00ed)<\/strong><\/strong><\/td>Testovac\u00ed nap\u011bt\u00ed (3U0 RMS)<\/strong><\/strong><\/td>Ekvivalentn\u00ed vrchol<\/strong> Nap\u011bt\u00ed<\/strong><\/strong><\/td>Doba trv\u00e1n\u00ed<\/strong><\/strong><\/td>Pr\u016fb\u011bh sign\u00e1lu<\/strong><\/strong><\/td><\/tr>
13,8 kV<\/td>8 kV<\/td>24 kV RMS<\/td>Maxim\u00e1ln\u00ed proud 34 kV<\/td>15\u201360 minut<\/td>Sinus 0,1 Hz<\/td><\/tr>
33 kV<\/td>19 kV<\/td>57 kV RMS<\/td>Max. nap\u011bt\u00ed 81 kV<\/td>15\u201360 minut<\/td>Sinus 0,1 Hz<\/td><\/tr><\/tbody><\/table><\/figure>

Toto jasn\u00e9 odd\u011blen\u00ed mezi RMS a Peak zaji\u0161\u0165uje, \u017ee vst\u0159ikovan\u00e1 nap\u011bt\u00ed odpov\u00edd\u00e1 krit\u00e9ri\u00edm SEC pro p\u0159ijet\u00ed. Pou\u017eit\u00ed pouze 24kV Peak nam\u00edsto RMS by sn\u00ed\u017eilo ochranu izolace a\u017e o 30%, co\u017e by vedlo k nep\u0159esn\u00e9mu zji\u0161t\u011bn\u00ed z\u00e1vad. Skute\u010dn\u00e9 poruchy v ter\u00e9nu toto probl\u00e9m potvrzuj\u00ed na mnoha m\u00edstech SEC, zejm\u00e9na v pou\u0161tn\u00edch podm\u00ednk\u00e1ch s opot\u0159eben\u00edm XLPE.<\/p>

\"Testov\u00e1n\u00ed<\/a><\/figure>

Praktick\u00e9 zku\u0161enosti a p\u0159\u00edm\u00e9 poznatky z projektu SEC<\/h2>

1. Z\u00e1kladn\u00ed principy a standardy<\/strong><\/strong><\/p>

Politika zabezpe\u010den\u00ed s\u00edt\u011b spole\u010dnosti Saudi Electricity Company (SEC) ukl\u00e1d\u00e1 povinnost prov\u00e1d\u011bt testy s velmi n\u00edzkou frekvenc\u00ed (VLF) u v\u0161ech kabel\u016f st\u0159edn\u00edho nap\u011bt\u00ed b\u011bhem uveden\u00ed do provozu a diagnostiky. Podm\u00ednky pro schv\u00e1len\u00ed SEC jsou obecn\u011b formulov\u00e1ny na z\u00e1klad\u011b princip\u016f mezin\u00e1rodn\u00edch norem IEEE 400.2 a IEC 60502-2. Dodr\u017eov\u00e1n\u00ed t\u011bchto norem zaji\u0161\u0165uje spolehliv\u00fd provoz kabel\u016f p\u0159i vysok\u00e9m zat\u00ed\u017een\u00ed a zabra\u0148uje n\u00e1kladn\u00fdm \u00faprav\u00e1m projektu v d\u016fsledku nespln\u011bn\u00ed testovac\u00edch po\u017eadavk\u016f.<\/p>

Podstatn\u00fdm po\u017eadavkem SEC je prov\u00e9st zkou\u0161ku odolnosti kabelu v\u016f\u010di nap\u011bt\u00ed pomoc\u00ed sinusov\u00e9 vlny VLF s frekvenc\u00ed 0,1 Hz.<\/p>

2. Specifick\u00e9 ukazatele parametr\u016f testu (krit\u00e9ria p\u0159ijatelnosti)<\/strong><\/strong><\/p>

Hlavn\u00edm m\u011b\u0159\u00edtkem v\u00fdkonnosti testu je schopnost kabelu vydr\u017eet nap\u011bt\u00ed 3U\u2080 RMS po dobu 15 a\u017e 60 minut.<\/p>

Krit\u00e9riem pro schv\u00e1len\u00ed je: \u017e\u00e1dn\u00e9 poruchy izolace a \u017e\u00e1dn\u00fd abnorm\u00e1ln\u00ed pr\u016ftok proudu b\u011bhem testu.<\/p>

Konkr\u00e9tn\u00ed hodnoty testu p\u0159epo\u010dten\u00e9 podle b\u011b\u017en\u00fdch syst\u00e9mov\u00fdch nap\u011bt\u00ed SEC jsou n\u00e1sleduj\u00edc\u00ed:<\/p>

Pro syst\u00e9mov\u00e9 kabely 13,8 kV:<\/p>

C\u00edlov\u00e1 zku\u0161ebn\u00ed nap\u011bt\u00ed (RMS): 24 kV RMS (odpov\u00eddaj\u00edc\u00ed maxim\u00e1ln\u00ed nap\u011bt\u00ed: p\u0159ibli\u017en\u011b 34 kV RMS)<\/p>

Pro syst\u00e9mov\u00e9 kabely 33 kV:<\/p>

C\u00edlov\u00e9 testovac\u00ed nap\u011bt\u00ed (RMS): 57 kV RMS (odpov\u00eddaj\u00edc\u00ed maxim\u00e1ln\u00ed nap\u011bt\u00ed: p\u0159ibli\u017en\u011b 81 kV RMS)<\/p>

<\/p>

3. Kritick\u00e9 varov\u00e1n\u00ed p\u0159i provozu: Zmaten\u00ed mezi RMS a maximem<\/strong><\/p>

To je nej\u010dast\u011bj\u0161\u00ed zdroj chyb na m\u00edst\u011b a mus\u00ed b\u00fdt prioritizov\u00e1no.<\/p>

Normy a po\u017eadavky SEC v\u017edy uv\u00e1d\u011bj\u00ed hodnoty RMS (Root Mean Square). Nicm\u00e9n\u011b testovac\u00ed za\u0159\u00edzen\u00ed VLF obvykle zobrazuje sou\u010dasn\u011b jak RMS, tak hodnoty Peak. Nespr\u00e1vn\u00e9 interpretov\u00e1n\u00ed t\u011bchto hodnot m\u016f\u017ee v\u00e9st k v\u00e1\u017en\u00fdm chyb\u00e1m p\u0159i testov\u00e1n\u00ed s nedostate\u010dn\u00fdm nap\u011bt\u00edm a k myln\u00fdm z\u00e1v\u011br\u016fm o \u201cp\u0159i\u0159azen\u00ed\u201d.<\/p>

Matematick\u00fd vztah (sinusoidaln\u00ed vlna): vrchol = RMS \u00d7 \u221a2 (p\u0159ibli\u017en\u011b 1,414).<\/p>

Kritick\u00fd p\u0159\u00edklad (kabel 33 kV): Aby bylo mo\u017en\u00e9 do kabelu o nap\u011bt\u00ed 33 kV vst\u0159elit po\u017eadovan\u00e9 RMS nap\u011bt\u00ed 57 kV, mus\u00ed v\u00e1\u0161 testovac\u00ed p\u0159\u00edstroj b\u00fdt schopen generovat p\u0159ibli\u017en\u011b 81 kV \u0161pi\u010dkov\u00e9ho nap\u011bt\u00ed.<\/p>

Z\u00e1vada za\u0159\u00edzen\u00ed: Mnoho standardn\u00edch komer\u010dn\u00edch \u201ctestovac\u00edch p\u0159\u00edstroj\u016f VLF s nap\u011bt\u00edm 60 kV\u201d m\u00e1 skute\u010dn\u00fd maxim\u00e1ln\u00ed v\u00fdstup pouze 60 kV (nebo o n\u011bco vy\u0161\u0161\u00ed). To znamen\u00e1, \u017ee absolutn\u011b nemohou spl\u0148ovat po\u017eadavek 3U\u2080 (57 kV RMS \/ 81 kV Peak) pro kabely o nap\u011bt\u00ed 33 kV. P\u0159ed zah\u00e1jen\u00edm pr\u00e1ce v\u017edy zkontrolujte schopnosti za\u0159\u00edzen\u00ed podle jeho specifikace.<\/p>

4. Projekty SEC \u2013 zku\u0161enosti a poznatky z praxe<\/strong><\/strong><\/p>

Na z\u00e1klad\u011b kontroly a anal\u00fdzy \u010detn\u00fdch test\u016f VLF na s\u00edt\u00edch 13,8 kV a 33 kV v regionu jsou zde kl\u00ed\u010dov\u00e9 praktick\u00e9 poznatky pro oblast:<\/p>

A. Omezen\u00ed kapacitnosti stroje a \u00faprava frekvence:<\/strong><\/p>

Standardn\u00ed frekvence VLF je 0,1 Hz. Nicm\u00e9n\u011b v distribu\u010dn\u00edch s\u00edt\u00edch SEC jsou b\u011b\u017en\u00e9 dlouh\u00e9 kabely s vysokou kapacitou (velk\u00e9 hodnoty \u00b5F). Pokud je kabel p\u0159\u00edli\u0161 dlouh\u00fd, za\u0159\u00edzen\u00ed VLF m\u016f\u017ee p\u0159estat fungovat kv\u016fli p\u0159ehur\u010den\u00ed p\u0159i frekvenci 0,1 Hz, proto\u017ee nem\u016f\u017ee poskytnout dostate\u010dn\u00fd proud pro nab\u00edjen\u00ed.<\/p>

Opat\u0159en\u00ed proti takov\u00fdm situac\u00edm: K dokon\u010den\u00ed testu budete mo\u017en\u00e1 muset sn\u00ed\u017eit frekvenci na 0,05 Hz nebo 0,02 Hz.<\/p>

Pozn\u00e1mka: A\u010dkoli IEEE umo\u017e\u0148uje pou\u017e\u00edvat ni\u017e\u0161\u00ed frekvence, technici spole\u010dnosti SEC obvykle preferuj\u00ed jejich udr\u017een\u00ed na \u00farovni 0,1 Hz, pokud je to mo\u017en\u00e9. Pokud je nutn\u00e9 sn\u00ed\u017eit frekvenci, ujist\u011bte se, \u017ee je to uvedeno v zpr\u00e1v\u011b o testu a obdr\u017e\u00edte p\u0159edchoz\u00ed souhlas od vedouc\u00edho in\u017een\u00fdra (SE).<\/p>

B. Z\u00e1v\u011bry jsou hlavn\u00edm nedostatkem:<\/strong><\/p>

Zku\u0161enosti ukazuj\u00ed, \u017ee v\u00edce ne\u017e 90% selh\u00e1n\u00ed VLF b\u011bhem uveden\u00ed do provozu nast\u00e1v\u00e1 na kone\u010dn\u00fdch body (kablov\u00e9 konektory\/nap\u00ednac\u00ed ku\u017eely) nebo v mezizubn\u00edch spoj\u00edch, nikoli v j\u00e1d\u0159e kabelov\u00e9 izolace. VLF je vynikaj\u00edc\u00ed p\u0159i detekci chyb v proveden\u00ed (jako jsou ne\u010dist\u00e9 \u0159ezy, zbytkov\u00e9 semi-konduktivn\u00ed vrstvy nebo vzduchov\u00e9 dutiny).<\/p>

Opat\u0159en\u00ed proti takov\u00fdm situac\u00edm: P\u0159ed testov\u00e1n\u00edm zajist\u011bte, aby konektory byly mimo\u0159\u00e1dn\u011b \u010dist\u00e9, a udr\u017eujte dostate\u010dn\u00fd bezpe\u010dnostn\u00ed prostor od zem\u011b, aby se zabr\u00e1nilo extern\u00edm p\u0159ep\u011bt\u00edm, kter\u00e9 nejsou skute\u010dn\u00fdmi poruchami t\u011bla kabelu.<\/p>

C. Pou\u017e\u00edvat re\u017eim \u201cBurn\u201d s opatrnost\u00ed:<\/strong><\/p>

Pokud kabel sel\u017ee p\u0159i zkou\u0161ce odolnosti v\u016f\u010di vysokofrekven\u010dn\u00edmu v\u00fdboji (VLF), nesm\u011bjte se bez souhlasu okam\u017eit\u011b p\u0159epnout do re\u017eimu \u201cSpalov\u00e1n\u00ed\u201d. A\u010dkoli spalov\u00e1n\u00ed sni\u017euje odpor poruchy a usnad\u0148uje lokalizaci poruchy (p\u0159i pou\u017eit\u00ed akustick\u00e9ho tlaku nebo v\u00fdboje), v\u00e1\u017en\u011b po\u0161kozuje izolaci obklopuj\u00edc\u00ed bod poruchy. To m\u016f\u017ee z jednoduch\u00e9 opravy spojen\u00ed ud\u011blat velk\u00fd projekt, kter\u00fd bude vy\u017eadovat v\u00fdm\u011bnu cel\u00e9 \u010d\u00e1sti kabelu.<\/p>

5. Pokro\u010dil\u00fd diagnostick\u00fd trend: Faktor disipace dielektrick\u00e9 vrstvy (Tan Delta)<\/strong><\/p>

A\u010dkoli testov\u00e1n\u00ed odolnosti VLF v\u016f\u010di nap\u011bt\u00ed je destruktivn\u00ed test s mo\u017enost\u00ed \u201cp\u0159iplatit\/zru\u0161it\u201d, SEC st\u00e1le v\u00edce podporuje (a n\u011bkdy vy\u017eaduje tak\u00e9 u kritick\u00fdch obvod\u016f) prov\u00e1d\u011bn\u00ed diagnostick\u00e9ho testu VLF Tan Delta (dielektrick\u00fd faktore disipace) p\u0159ed proveden\u00edm testu odolnosti v\u016f\u010di vysok\u00e9mu nap\u011bt\u00ed. To umo\u017e\u0148uje nedestruktivn\u00ed posouzen\u00ed stavu izolace p\u0159ed podroben\u00edm kabelu vysok\u00e9mu zat\u00ed\u017een\u00ed.<\/p>

\"\"<\/figure>","protected":false},"excerpt":{"rendered":"

Testov\u00e1n\u00ed s velmi n\u00edzkou frekvenc\u00ed (VLF) pro v\u0161echny kabely st\u0159edn\u00edho nap\u011bt\u00ed b\u011bhem uveden\u00ed do provozu a diagnostiky. Po\u017eadavky na schv\u00e1len\u00ed SEC jsou obecn\u011b formulov\u00e1ny na z\u00e1klad\u011b princip\u016f mezin\u00e1rodn\u00edch norem IEEE 400.2 a IEC 60502-2.<\/p>","protected":false},"author":1,"featured_media":6391,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_seopress_robots_primary_cat":"none","_seopress_titles_title":"","_seopress_titles_desc":"","_seopress_robots_index":"","footnotes":""},"categories":[40],"tags":[],"_links":{"self":[{"href":"https:\/\/kvhipot.com\/cs\/wp-json\/wp\/v2\/posts\/6387"}],"collection":[{"href":"https:\/\/kvhipot.com\/cs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kvhipot.com\/cs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kvhipot.com\/cs\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/kvhipot.com\/cs\/wp-json\/wp\/v2\/comments?post=6387"}],"version-history":[{"count":5,"href":"https:\/\/kvhipot.com\/cs\/wp-json\/wp\/v2\/posts\/6387\/revisions"}],"predecessor-version":[{"id":6396,"href":"https:\/\/kvhipot.com\/cs\/wp-json\/wp\/v2\/posts\/6387\/revisions\/6396"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/kvhipot.com\/cs\/wp-json\/wp\/v2\/media\/6391"}],"wp:attachment":[{"href":"https:\/\/kvhipot.com\/cs\/wp-json\/wp\/v2\/media?parent=6387"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kvhipot.com\/cs\/wp-json\/wp\/v2\/categories?post=6387"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kvhipot.com\/cs\/wp-json\/wp\/v2\/tags?post=6387"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}