{"id":6420,"date":"2026-04-09T15:20:05","date_gmt":"2026-04-09T07:20:05","guid":{"rendered":"https:\/\/kvhipot.com\/?p=6420"},"modified":"2026-04-09T15:20:07","modified_gmt":"2026-04-09T07:20:07","slug":"kiem-tra-cap-vlf-la-gi","status":"publish","type":"post","link":"https:\/\/kvhipot.com\/vi\/what-is-vlf-cable-testing\/","title":{"rendered":"Ki\u1ec3m tra c\u00e1p VLF l\u00e0 g\u00ec?"},"content":{"rendered":"

<\/h1>

S\u1ef1 c\u1ed1 c\u00e1p g\u00e2y ra c\u00e1c v\u1ee5 m\u1ea5t \u0111i\u1ec7n tr\u00ean di\u1ec7n r\u1ed9ng v\u00e0 khi\u1ebfn kh\u00e1ch h\u00e0ng ph\u1eabn n\u1ed9. Vi\u1ec7c ph\u00e1t hi\u1ec7n c\u00e1c khuy\u1ebft t\u1eadt ti\u1ec1m \u1ea9n tr\u01b0\u1edbc khi c\u1ea5p \u0111i\u1ec7n l\u00e0 r\u1ea5t kh\u00f3 kh\u0103n. Ki\u1ec3m tra c\u00e1p b\u1eb1ng ph\u01b0\u01a1ng ph\u00e1p VLF gi\u1ea3i quy\u1ebft v\u1ea5n \u0111\u1ec1 n\u00e0y m\u1ed9t c\u00e1ch an to\u00e0n v\u00e0 d\u1ec5 d\u00e0ng. Ph\u01b0\u01a1ng ph\u00e1p ki\u1ec3m tra c\u00e1p VLF s\u1eed d\u1ee5ng \u0111i\u1ec7n \u00e1p xoay chi\u1ec1u t\u1ea7n s\u1ed1 r\u1ea5t th\u1ea5p (0,1 Hz) \u0111\u1ec3 ki\u1ec3m tra l\u1edbp c\u00e1ch \u0111i\u1ec7n c\u1ee7a c\u00e1p trung v\u00e0 cao \u00e1p. Ph\u01b0\u01a1ng ph\u00e1p n\u00e0y gi\u00fap ph\u00e1t hi\u1ec7n c\u00e1c \u0111i\u1ec3m y\u1ebfu tr\u00ean c\u00e1p XLPE m\u00e0 kh\u00f4ng g\u00e2y h\u01b0 h\u1ea1i cho ch\u00fang. Ph\u01b0\u01a1ng ph\u00e1p n\u00e0y thay th\u1ebf ph\u01b0\u01a1ng ph\u00e1p ki\u1ec3m tra b\u1eb1ng \u0111i\u1ec7n \u00e1p m\u1ed9t chi\u1ec1u (DC) c\u0169, \u0111\u1ea3m b\u1ea3o m\u1ea1ng l\u01b0\u1edbi \u0111i\u1ec7n c\u1ee7a qu\u00fd v\u1ecb an to\u00e0n tr\u01b0\u1edbc khi \u0111\u01b0a v\u00e0o v\u1eadn h\u00e0nh ch\u00ednh th\u1ee9c.<\/strong> T\u00f4i n\u00f3i chuy\u1ec7n v\u1edbi c\u00e1c nh\u00e0 th\u1ea7u EPC h\u00e0ng ng\u00e0y. H\u1ecd lu\u00f4n lo l\u1eafng v\u1ec1 vi\u1ec7c ki\u1ec3m tra c\u00e1p. H\u1ecd mu\u1ed1n bi\u1ebft li\u1ec7u vi\u1ec7c ki\u1ec3m tra n\u00e0y c\u00f3 l\u00e0m h\u1ecfng nh\u1eefng s\u1ee3i c\u00e1p m\u1edbi toanh c\u1ee7a h\u1ecd hay kh\u00f4ng. H\u1ecd h\u1ecfi t\u00f4i li\u1ec7u \u0111\u00e2y c\u00f3 ph\u1ea3i ch\u1ec9 l\u00e0 m\u1ed9t b\u01b0\u1edbc th\u1eeba th\u00e3i n\u1eefa hay kh\u00f4ng. H\u00e3y c\u00f9ng xem x\u00e9t nh\u1eefng s\u1ef1 th\u1eadt th\u1ef1c t\u1ebf v\u1ec1 ph\u01b0\u01a1ng ph\u00e1p ki\u1ec3m tra n\u00e0y.<\/p>

Vi\u1ec7c ki\u1ec3m tra c\u00e1p VLF c\u00f3 g\u00e2y h\u01b0 h\u1ecfng kh\u00f4ng?<\/h2>

Vi\u1ec7c th\u1eed nghi\u1ec7m c\u00e1c lo\u1ea1i c\u00e1p m\u1edbi \u1edf \u0111i\u1ec7n \u00e1p cao khi\u1ebfn nhi\u1ec1u k\u1ef9 s\u01b0 lo ng\u1ea1i. Vi\u1ec7c l\u00e0m h\u1ecfng m\u1ed9t s\u1ee3i c\u00e1p c\u00f2n t\u1ed1t trong qu\u00e1 tr\u00ecnh th\u1eed nghi\u1ec7m s\u1ebd g\u00e2y l\u00e3ng ph\u00ed th\u1eddi gian v\u00e0 ti\u1ec1n b\u1ea1c. Th\u1eed nghi\u1ec7m VLF r\u1ea5t an to\u00e0n v\u00e0 gi\u00fap ng\u0103n ng\u1eeba c\u00e1c v\u1ee5 ch\u00e1y b\u1ea5t ng\u1edd.\u00a0Ki\u1ec3m tra c\u00e1p VLF l\u00e0 ph\u01b0\u01a1ng ph\u00e1p ki\u1ec3m tra kh\u00f4ng ph\u00e1 h\u1ee7y d\u00e0nh cho c\u00e1c s\u1ee3i c\u00e1p c\u00f2n nguy\u00ean v\u1eb9n. Ph\u01b0\u01a1ng ph\u00e1p n\u00e0y ch\u1ec9 l\u00e0m h\u1ecfng nh\u1eefng s\u1ee3i c\u00e1p \u0111\u00e3 c\u00f3 khuy\u1ebft t\u1eadt c\u00e1ch \u0111i\u1ec7n nghi\u00eam tr\u1ecdng. N\u1ebfu s\u1ee3i c\u00e1p c\u1ee7a b\u1ea1n c\u00f2n t\u1ed1t, vi\u1ec7c ki\u1ec3m tra t\u1ea7n s\u1ed1 th\u1ea5p s\u1ebd ho\u00e0n to\u00e0n kh\u00f4ng g\u00e2y h\u1ea1i cho n\u00f3. Ph\u01b0\u01a1ng ph\u00e1p n\u00e0y \u0111\u1ea3m b\u1ea3o s\u1ee3i c\u00e1p c\u1ee7a b\u1ea1n duy tr\u00ec \u0111\u01b0\u1ee3c to\u00e0n b\u1ed9 tu\u1ed5i th\u1ecd c\u1ee7a n\u00f3.<\/strong>\u00a0! <\/p>

Nhi\u1ec1u ng\u01b0\u1eddi h\u1ecfi t\u00f4i li\u1ec7u vi\u1ec7c th\u1eed nghi\u1ec7m VLF c\u00f3 l\u00e0m h\u1ecfng c\u00e1c d\u00e2y c\u00e1p \u0111\u1eaft ti\u1ec1n c\u1ee7a h\u1ecd hay kh\u00f4ng. \u0110\u1ec3 tr\u1ea3 l\u1eddi c\u00e2u h\u1ecfi n\u00e0y, ch\u00fang ta c\u1ea7n suy ngh\u0129 xem t\u1eeb \u201cph\u00e1 h\u1ee7y\u201d th\u1ef1c s\u1ef1 c\u00f3 ngh\u0129a l\u00e0 g\u00ec. Th\u1eed nghi\u1ec7m VLF l\u00e0 m\u1ed9t \u201cth\u1eed nghi\u1ec7m ch\u1ecbu \u0111\u1ef1ng\u201d. \u0110i\u1ec1u n\u00e0y c\u00f3 ngh\u0129a l\u00e0 ch\u00fang ta s\u1ebd \u00e1p d\u1ee5ng m\u1ed9t \u0111i\u1ec7n \u00e1p cao v\u00e0o d\u00e2y c\u00e1p trong m\u1ed9t kho\u1ea3ng th\u1eddi gian c\u1ee5 th\u1ec3. Th\u00f4ng th\u01b0\u1eddng, ch\u00fang ta \u00e1p d\u1ee5ng \u0111i\u1ec7n \u00e1p g\u1ea5p ba l\u1ea7n \u0111i\u1ec7n \u00e1p l\u00e0m vi\u1ec7c b\u00ecnh th\u01b0\u1eddng.<\/p>

<\/p>

N\u1ebfu d\u00e2y c\u00e1p ho\u00e0n to\u00e0n nguy\u00ean v\u1eb9n, n\u00f3 s\u1ebd d\u1ec5 d\u00e0ng ch\u1ecbu \u0111\u01b0\u1ee3c \u00e1p l\u1ef1c n\u00e0y. L\u1edbp c\u00e1ch \u0111i\u1ec7n b\u1eb1ng nh\u1ef1a s\u1ebd kh\u00f4ng b\u1ecb l\u00e3o h\u00f3a nhanh h\u01a1n. D\u00e2y c\u00e1p s\u1ebd kh\u00f4ng b\u1ecb ch\u1ea3y. D\u00e2y c\u00e1p v\u1eabn ho\u00e0n to\u00e0n an to\u00e0n. Nh\u01b0ng tr\u00ean c\u00e1c c\u00f4ng tr\u01b0\u1eddng th\u1ef1c t\u1ebf, s\u1ef1 c\u1ed1 v\u1eabn c\u00f3 th\u1ec3 x\u1ea3y ra. M\u1ed9t c\u00f4ng nh\u00e2n m\u1eafc l\u1ed7i khi n\u1ed1i hai s\u1ee3i c\u00e1p. \u0110i\u1ec3m n\u1ed1i \u0111\u00f3 tr\u1edf th\u00e0nh \u0111i\u1ec3m y\u1ebfu. B\u1ee5i b\u1ea9n ho\u1eb7c n\u01b0\u1edbc x\u00e2m nh\u1eadp v\u00e0o b\u00ean trong d\u00e2y c\u00e1p trong qu\u00e1 tr\u00ecnh l\u1eafp \u0111\u1eb7t. L\u1edbp c\u00e1ch \u0111i\u1ec7n tr\u1edf n\u00ean y\u1ebfu \u0111i. Khi ch\u00fang ta \u00e1p d\u1ee5ng \u0111i\u1ec7n \u00e1p VLF, m\u00e1y s\u1ebd ph\u00e1t hi\u1ec7n ra \u0111i\u1ec3m y\u1ebfu n\u00e0y. \u0110i\u1ec7n \u00e1p s\u1ebd bu\u1ed9c m\u1ed1i n\u1ed1i k\u00e9m ch\u1ea5t l\u01b0\u1ee3ng ph\u1ea3i h\u1ecfng. C\u00e1p b\u1ecb h\u1ecfng trong qu\u00e1 tr\u00ecnh th\u1eed nghi\u1ec7m. \u0110i\u1ec1u n\u00e0y c\u00f3 ph\u1ea3i l\u00e0 \u0111i\u1ec1u x\u1ea5u kh\u00f4ng? Kh\u00f4ng. \u0110\u00e2y l\u00e0 m\u1ed9t \u0111i\u1ec1u r\u1ea5t t\u1ed1t. B\u1ea1n mu\u1ed1n d\u00e2y c\u00e1p b\u1ecb \u0111\u1ee9t khi \u0111ang ki\u1ec3m tra t\u1ea1i m\u1ed9t c\u00f4ng tr\u01b0\u1eddng tr\u1ed1ng. B\u1ea1n kh\u00f4ng mu\u1ed1n n\u00f3 ph\u00e1t n\u1ed5 ba th\u00e1ng sau \u0111\u00f3. M\u1ed9t v\u1ee5 n\u1ed5 sau n\u00e0y c\u00f3 th\u1ec3 ph\u00e1 h\u1ee7y c\u1ea3 m\u1ed9t nh\u00e0 m\u00e1y.<\/p>

M\u1ed9t c\u00e2u chuy\u1ec7n c\u00f3 th\u1eadt t\u1eeb \u1ea2 R\u1eadp X\u00ea \u00dat<\/h3>

N\u0103m ngo\u00e1i, m\u1ed9t nh\u00e0 th\u1ea7u EPC t\u1ea1i \u1ea2 R\u1eadp X\u00ea \u00dat \u0111\u00e3 mua m\u1ed9t m\u00e1y ki\u1ec3m tra VLF. H\u1ecd \u0111\u00e3 l\u1eafp \u0111\u1eb7t m\u1ed9t \u0111\u01b0\u1eddng c\u00e1p d\u00e0i 5 kil\u00f4m\u00e9t, \u0111i\u1ec7n \u00e1p 33 kV cho m\u1ed9t trang tr\u1ea1i n\u0103ng l\u01b0\u1ee3ng m\u1eb7t tr\u1eddi m\u1edbi. Ng\u01b0\u1eddi qu\u1ea3n l\u00fd d\u1ef1 \u00e1n lo ng\u1ea1i kh\u00f4ng d\u00e1m ti\u1ebfn h\u00e0nh ki\u1ec3m tra. \u00d4ng \u1ea5y cho r\u1eb1ng \u0111i\u1ec7n \u00e1p cao s\u1ebd l\u00e0m h\u1ecfng to\u00e0n b\u1ed9 \u0111\u01b0\u1eddng c\u00e1p. T\u00f4i \u0111\u00e3 gi\u1ea3i th\u00edch cho \u00f4ng \u1ea5y v\u1ec1 nguy\u00ean l\u00fd v\u1eadt l\u00fd c\u1ee7a ph\u01b0\u01a1ng ph\u00e1p VLF. Cu\u1ed1i c\u00f9ng, h\u1ecd \u0111\u00e3 ti\u1ebfn h\u00e0nh ki\u1ec3m tra. Th\u1eed nghi\u1ec7m th\u1ea5t b\u1ea1i v\u00e0o ph\u00fat th\u1ee9 15. Ng\u01b0\u1eddi qu\u1ea3n l\u00fd r\u1ea5t t\u1ee9c gi\u1eadn. Anh \u1ea5y g\u1ecdi cho t\u00f4i. Anh \u1ea5y n\u00f3i r\u1eb1ng m\u00e1y c\u1ee7a t\u00f4i \u0111\u00e3 ph\u00e1 h\u1ee7y \u0111\u01b0\u1eddng c\u00e1p m\u1edbi c\u1ee7a anh \u1ea5y. T\u00f4i b\u1ea3o anh \u1ea5y t\u00ecm v\u1ecb tr\u00ed ch\u00ednh x\u00e1c c\u1ee7a s\u1ef1 c\u1ed1. H\u1ecd \u0111\u00e3 s\u1eed d\u1ee5ng m\u00e1y d\u00f2 s\u1ef1 c\u1ed1 c\u00e1p. H\u1ecd \u0111\u00e0o \u0111\u1ea5t l\u00ean. H\u1ecd ph\u00e1t hi\u1ec7n ra m\u1ed9t v\u1ebft c\u1eaft s\u00e2u nh\u01b0 l\u01b0\u1ee1i dao tr\u00ean l\u1edbp c\u00e1ch \u0111i\u1ec7n c\u1ee7a \u0111\u01b0\u1eddng c\u00e1p. M\u1ed9t c\u00f4ng nh\u00e2n b\u1ea5t c\u1ea9n \u0111\u00e3 l\u00e0m r\u01a1i d\u1ee5ng c\u1ee5 l\u00ean d\u00e2y c\u00e1p tr\u01b0\u1edbc khi ch\u00f4n n\u00f3 xu\u1ed1ng. M\u00e1y c\u1ee7a ch\u00fang t\u00f4i kh\u00f4ng l\u00e0m h\u1ecfng m\u1ed9t s\u1ee3i c\u00e1p c\u00f2n t\u1ed1t. M\u00e1y c\u1ee7a ch\u00fang t\u00f4i \u0111\u00e3 ph\u00e1t hi\u1ec7n ra m\u1ed9t m\u1ed1i nguy hi\u1ec3m ti\u1ec1m \u1ea9n. N\u00f3 \u0111\u00e3 ph\u00e1 h\u1ee7y \u0111o\u1ea1n c\u00e1p b\u1ecb h\u1ecfng tr\u01b0\u1edbc khi n\u00f3 c\u00f3 th\u1ec3 g\u00e2y ra m\u1ed9t th\u1ea3m h\u1ecda l\u1edbn. H\u1ecd \u0111\u00e3 s\u1eeda ch\u1eefa \u0111o\u1ea1n c\u00e1p nh\u1ecf \u0111\u00f3. H\u1ecd ki\u1ec3m tra l\u1ea1i. K\u1ebft qu\u1ea3 \u0111\u1ea1t y\u00eau c\u1ea7u.<\/p>

\"\"<\/figure>

C\u00e1ch VLF b\u1ea3o v\u1ec7 kho\u1ea3n \u0111\u1ea7u t\u01b0 c\u1ee7a b\u1ea1n<\/h3>

Ch\u00fang ta c\u00f3 th\u1ec3 xem x\u00e9t k\u1ebft qu\u1ea3 c\u1ee7a m\u1ed9t b\u00e0i ki\u1ec3m tra VLF m\u1ed9t c\u00e1ch \u0111\u01a1n gi\u1ea3n. \u0110i\u1ec1u n\u00e0y gi\u00fap ch\u00fang ta hi\u1ec3u \u0111\u01b0\u1ee3c gi\u00e1 tr\u1ecb th\u1ef1c s\u1ef1 c\u1ee7a n\u00f3.<\/p>

T\u00ecnh tr\u1ea1ng c\u00e1p<\/th>K\u1ebft qu\u1ea3 ki\u1ec3m tra<\/th>K\u1ebft qu\u1ea3 trong th\u1ef1c t\u1ebf<\/th><\/tr><\/thead>
D\u00e2y c\u00e1p t\u1ed1t cho s\u1ee9c kh\u1ecfe<\/strong><\/td>\u0110\u1ea1t y\u00eau c\u1ea7u trong b\u00e0i ki\u1ec3m tra 60 ph\u00fat.<\/td>Ho\u1ea1t \u0111\u1ed9ng an to\u00e0n trong 30 n\u0103m. Kh\u00f4ng c\u00f3 h\u01b0 h\u1ecfng n\u00e0o do qu\u00e1 tr\u00ecnh th\u1eed nghi\u1ec7m g\u00e2y ra.<\/td><\/tr>
V\u1ebft c\u1eaft tr\u00ean l\u1edbp c\u00e1ch nhi\u1ec7t<\/strong><\/td>G\u1eb7p l\u1ed7i trong qu\u00e1 tr\u00ecnh ki\u1ec3m tra.<\/td>B\u1ea1n h\u00e3y s\u1eeda ch\u1ed7 h\u01b0 h\u1ecfng ngay b\u00e2y gi\u1edd v\u1edbi chi ph\u00ed th\u1ea5p.<\/td><\/tr>
N\u01b0\u1edbc trong kh\u1edbp<\/strong><\/td>Th\u1ea5t b\u1ea1i ngay l\u1eadp t\u1ee9c.<\/td>B\u1ea1n ph\u1ea3i thay th\u1ebf kh\u1edbp n\u1ed1i tr\u01b0\u1edbc khi ch\u00f4n n\u00f3 xu\u1ed1ng \u0111\u1ea5t.<\/td><\/tr>
Ch\u01b0a \u0111\u01b0\u1ee3c ki\u1ec3m tra ch\u00fat n\u00e0o<\/strong><\/td>T\u00ecnh tr\u1ea1ng ch\u01b0a r\u00f5.<\/td>Sau n\u00e0y s\u1ebd ph\u00e1t n\u1ed5. Chi ph\u00ed \u0111\u00e0o l\u00ean v\u00e0 s\u1eeda ch\u1eefa s\u1ebd r\u1ea5t t\u1ed1n k\u00e9m.<\/td><\/tr><\/tbody><\/table><\/figure>

Do \u0111\u00f3, VLF ch\u1ec9 g\u00e2y h\u1ea1i cho c\u00e1c s\u1ef1 c\u1ed1 ti\u1ec1m \u1ea9n. N\u00f3 ho\u1ea1t \u0111\u1ed9ng nh\u01b0 m\u1ed9t nh\u00e2n vi\u00ean ki\u1ec3m tra ch\u1ea5t l\u01b0\u1ee3ng nghi\u00eam ng\u1eb7t cho m\u1ea1ng l\u01b0\u1edbi \u0111i\u1ec7n c\u1ee7a b\u1ea1n. N\u00f3 kh\u00f4ng g\u00e2y h\u1ea1i cho c\u00e1c thi\u1ebft b\u1ecb ho\u1ea1t \u0111\u1ed9ng t\u1ed1t.<\/p>

Khi ki\u1ec3m tra c\u00e1p cao \u00e1p, t\u1ea1i sao ch\u00fang ta ch\u1ec9 s\u1eed d\u1ee5ng t\u1ea7n s\u1ed1 r\u1ea5t th\u1ea5p (VLF) m\u00e0 kh\u00f4ng s\u1eed d\u1ee5ng t\u1ea7n s\u1ed1 trung b\u00ecnh hay cao?<\/h2>

Vi\u1ec7c v\u1eadn chuy\u1ec3n c\u00e1c m\u00e1y th\u1eed nghi\u1ec7m c\u1ed3ng k\u1ec1nh \u0111\u1ebfn c\u00e1c \u0111\u1ecba \u0111i\u1ec3m xa x\u00f4i th\u1ef1c s\u1ef1 l\u00e0 m\u1ed9t c\u01a1n \u00e1c m\u1ed9ng. C\u00e1c m\u00e1y th\u1eed nghi\u1ec7m AC t\u1ea7n s\u1ed1 cao qu\u00e1 to v\u00e0 n\u1eb7ng \u0111\u1ec3 s\u1eed d\u1ee5ng t\u1ea1i hi\u1ec7n tr\u01b0\u1eddng. T\u1ea7n s\u1ed1 VLF gi\u1ea3i quy\u1ebft ngay l\u1eadp t\u1ee9c v\u1ea5n \u0111\u1ec1 tr\u1ecdng l\u01b0\u1ee3ng kh\u1ed5ng l\u1ed3 n\u00e0y.\u00a0Ch\u00fang t\u00f4i s\u1eed d\u1ee5ng t\u1ea7n s\u1ed1 r\u1ea5t th\u1ea5p (0,1 Hz) v\u00ec c\u00f4ng ngh\u1ec7 n\u00e0y ti\u00eau th\u1ee5 c\u00f4ng su\u1ea5t \u00edt h\u01a1n 600 l\u1ea7n so v\u1edbi ph\u01b0\u01a1ng ph\u00e1p th\u1eed nghi\u1ec7m ti\u00eau chu\u1ea9n \u1edf t\u1ea7n s\u1ed1 60 Hz. \u0110i\u1ec1u n\u00e0y gi\u00fap m\u00e1y th\u1eed nghi\u1ec7m c\u00f3 k\u00edch th\u01b0\u1edbc nh\u1ecf g\u1ecdn, tr\u1ecdng l\u01b0\u1ee3ng nh\u1eb9 v\u00e0 d\u1ec5 d\u00e0ng mang theo. Nh\u1edd \u0111\u00f3, vi\u1ec7c th\u1eed nghi\u1ec7m t\u1ea1i hi\u1ec7n tr\u01b0\u1eddng \u0111\u1ed1i v\u1edbi c\u00e1c d\u00e2y c\u00e1p cao \u00e1p d\u00e0i tr\u1edf n\u00ean kh\u1ea3 thi.<\/strong>\u00a0<\/p>

\u00a0\u0110\u1ec3 hi\u1ec3u t\u1ea1i sao ch\u00fang ta s\u1eed d\u1ee5ng t\u1ea7n s\u1ed1 0,1 Hz, ch\u00fang ta c\u1ea7n t\u00ecm hi\u1ec3u c\u00e1ch th\u1ee9c ho\u1ea1t \u0111\u1ed9ng c\u1ee7a d\u00e2y c\u00e1p \u0111i\u1ec7n. M\u1ed9t s\u1ee3i c\u00e1p \u0111i\u1ec7n d\u00e0i kh\u00f4ng ch\u1ec9 \u0111\u01a1n thu\u1ea7n l\u00e0 m\u1ed9t s\u1ee3i d\u00e2y. N\u00f3 ho\u1ea1t \u0111\u1ed9ng y h\u1ec7t nh\u01b0 m\u1ed9t t\u1ee5 \u0111i\u1ec7n kh\u1ed5ng l\u1ed3. T\u1ee5 \u0111i\u1ec7n l\u00e0 m\u1ed9t linh ki\u1ec7n \u0111i\u1ec7n t\u1eed. N\u00f3 c\u00f3 ch\u1ee9c n\u0103ng t\u00edch tr\u1eef n\u0103ng l\u01b0\u1ee3ng. D\u00e2y c\u00e1p c\u00e0ng d\u00e0i, l\u01b0\u1ee3ng n\u0103ng l\u01b0\u1ee3ng n\u00f3 t\u00edch tr\u1eef \u0111\u01b0\u1ee3c c\u00e0ng nhi\u1ec1u. \u0110i\u1ec7n \u00e1p c\u00e0ng cao, n\u00f3 c\u00e0ng l\u01b0u tr\u1eef \u0111\u01b0\u1ee3c nhi\u1ec1u n\u0103ng l\u01b0\u1ee3ng. Khi b\u1ea1n ki\u1ec3m tra m\u1ed9t d\u00e2y c\u00e1p b\u1eb1ng d\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u (AC), b\u1ea1n ph\u1ea3i \u0111\u1ea9y \u0111i\u1ec7n v\u00e0o t\u1ee5 \u0111i\u1ec7n kh\u1ed5ng l\u1ed3 n\u00e0y. B\u1ea1n \u0111\u1ea9y \u0111i\u1ec7n v\u00e0o. Sau \u0111\u00f3, b\u1ea1n r\u00fat \u0111i\u1ec7n ra. B\u1ea1n th\u1ef1c hi\u1ec7n vi\u1ec7c n\u00e0y nhi\u1ec1u l\u1ea7n trong m\u1ed9t gi\u00e2y.

Th\u00eam v\u00e0o ti\u1ec7n \u00edch m\u1edf r\u1ed9ng c\u1ee7a Photoshop<\/title><\/path><\/path><\/path><\/svg><\/div><\/p>

V\u1ea5n \u0111\u1ec1 v\u1edbi t\u1ea7n s\u1ed1 50 Hz ho\u1eb7c 60 Hz<\/h3>

N\u1ebfu b\u1ea1n s\u1eed d\u1ee5ng t\u1ea7n s\u1ed1 l\u01b0\u1edbi \u0111i\u1ec7n th\u00f4ng th\u01b0\u1eddng, nh\u01b0 50 Hz ho\u1eb7c 60 Hz, b\u1ea1n ph\u1ea3i th\u1ef1c hi\u1ec7n qu\u00e1 tr\u00ecnh \u0111\u1ea9y v\u00e0 k\u00e9o 50 ho\u1eb7c 60 l\u1ea7n m\u1ed7i gi\u00e2y. Vi\u1ec7c \u0111\u1ea9y \u0111i\u1ec7n \u00e1p cao v\u00e0o m\u1ed9t s\u1ee3i c\u00e1p d\u00e0i 50 l\u1ea7n m\u1ed7i gi\u00e2y l\u00e0 m\u1ed9t c\u00f4ng vi\u1ec7c v\u00f4 c\u00f9ng n\u1eb7ng nh\u1ecdc. N\u00f3 \u0111\u00f2i h\u1ecfi m\u1ed9t l\u01b0\u1ee3ng d\u00f2ng \u0111i\u1ec7n kh\u1ed5ng l\u1ed3. \u0110\u1ec3 cung c\u1ea5p d\u00f2ng \u0111i\u1ec7n kh\u1ed5ng l\u1ed3 n\u00e0y, b\u1ea1n c\u1ea7n m\u1ed9t m\u00e1y th\u1eed nghi\u1ec7m c\u1ee1 l\u1edbn. N\u1ebfu b\u1ea1n mu\u1ed1n th\u1eed nghi\u1ec7m m\u1ed9t s\u1ee3i c\u00e1p 33kV d\u00e0i 10 km \u1edf t\u1ea7n s\u1ed1 50 Hz, m\u00e1y th\u1eed nghi\u1ec7m c\u1ee7a b\u1ea1n s\u1ebd c\u00f3 k\u00edch th\u01b0\u1edbc b\u1eb1ng m\u1ed9t container v\u1eadn chuy\u1ec3n l\u1edbn. N\u00f3 s\u1ebd n\u1eb7ng h\u00e0ng ngh\u00ecn kg. B\u1ea1n s\u1ebd c\u1ea7n m\u1ed9t chi\u1ebfc xe t\u1ea3i l\u1edbn \u0111\u1ec3 v\u1eadn chuy\u1ec3n n\u00f3. B\u1ea1n s\u1ebd c\u1ea7n m\u1ed9t c\u1ea7n c\u1ea9u \u0111\u1ec3 n\u00e2ng n\u00f3 l\u00ean. \u0110i\u1ec1u n\u00e0y l\u00e0 kh\u00f4ng th\u1ec3 \u0111\u1ed1i v\u1edbi c\u00e1c kh\u00e1ch h\u00e0ng c\u1ee7a t\u00f4i. C\u00e1c kh\u00e1ch h\u00e0ng c\u1ee7a t\u00f4i l\u00e0m vi\u1ec7c \u1edf sa m\u1ea1c. H\u1ecd l\u00e0m vi\u1ec7c tr\u00ean n\u00fai. H\u1ecd l\u00e0m vi\u1ec7c tr\u00ean nh\u1eefng con \u0111\u01b0\u1eddng \u0111\u00f4ng \u0111\u00fac trong th\u00e0nh ph\u1ed1. H\u1ecd kh\u00f4ng th\u1ec3 mang c\u1ea7n c\u1ea9u \u0111\u1ebfn m\u1ecdi \u0111\u1ecba \u0111i\u1ec3m th\u1eed nghi\u1ec7m.<\/p>

S\u1ee9c m\u1ea1nh k\u1ef3 di\u1ec7u c\u1ee7a t\u1ea7n s\u1ed1 0,1 Hz<\/h3>

\u0110\u00e2y ch\u00ednh l\u00e0 l\u00fac nh\u1eefng ph\u00e9p t\u00ednh \u0111\u01a1n gi\u1ea3n gi\u00fap ch\u00fang ta. C\u00f3 m\u1ed9t quy lu\u1eadt c\u01a1 b\u1ea3n trong \u0111i\u1ec7n h\u1ecdc: D\u00f2ng \u0111i\u1ec7n c\u1ea7n thi\u1ebft t\u1ef7 l\u1ec7 thu\u1eadn v\u1edbi t\u1ea7n s\u1ed1. N\u1ebfu gi\u1ea3m t\u1ea7n s\u1ed1, d\u00f2ng \u0111i\u1ec7n c\u0169ng s\u1ebd gi\u1ea3m theo. N\u1ebfu ch\u00fang ta thay \u0111\u1ed5i t\u1ea7n s\u1ed1 t\u1eeb 60 Hz xu\u1ed1ng c\u00f2n 0,1 Hz, t\u1ea7n s\u1ed1 s\u1ebd nh\u1ecf \u0111i 600 l\u1ea7n. V\u00ec t\u1ea7n s\u1ed1 nh\u1ecf h\u01a1n 600 l\u1ea7n, n\u00ean d\u00f2ng \u0111i\u1ec7n c\u1ea7n thi\u1ebft c\u0169ng nh\u1ecf h\u01a1n 600 l\u1ea7n. C\u00f4ng su\u1ea5t c\u1ea7n thi\u1ebft c\u0169ng nh\u1ecf h\u01a1n 600 l\u1ea7n. V\u00ec c\u1ea7n \u00edt c\u00f4ng su\u1ea5t h\u01a1n, ch\u00fang ta c\u00f3 th\u1ec3 ch\u1ebf t\u1ea1o m\u1ed9t m\u00e1y m\u00f3c nh\u1ecf h\u01a1n r\u1ea5t nhi\u1ec1u.<\/p>

M\u1ed9t c\u00e2u chuy\u1ec7n c\u00f3 th\u1eadt t\u1eeb Vi\u1ec7t Nam<\/h3>

T\u00f4i c\u00f3 m\u1ed9t kh\u00e1ch h\u00e0ng \u1edf Vi\u1ec7t Nam. H\u1ecd cung c\u1ea5p d\u1ecbch v\u1ee5 \u0111i\u1ec7n cho c\u00e1c trang tr\u1ea1i gi\u00f3. V\u00e0i n\u0103m tr\u01b0\u1edbc, h\u1ecd \u0111\u00e3 s\u1eed d\u1ee5ng m\u1ed9t h\u1ec7 th\u1ed1ng ki\u1ec3m tra c\u1ed9ng h\u01b0\u1edfng AC c\u1ee1 l\u1edbn. H\u1ecd c\u1ea7n ki\u1ec3m tra m\u1ed9t s\u1ee3i c\u00e1p \u1edf \u0111\u1ec9nh n\u00fai. Chi\u1ebfc xe t\u1ea3i kh\u00f4ng th\u1ec3 leo l\u00ean con \u0111\u01b0\u1eddng \u0111\u1ea5t \u0111\u00f3. H\u1ecd bu\u1ed9c ph\u1ea3i t\u1ea1m d\u1eebng c\u00f4ng vi\u1ec7c. H\u1ecd \u0111\u00e3 g\u1ecdi cho t\u00f4i \u0111\u1ec3 nh\u1edd gi\u00fap \u0111\u1ee1. T\u00f4i \u0111\u00e3 b\u00e1n cho h\u1ecd m\u1ed9t m\u00e1y ki\u1ec3m tra HIPOT VLF. M\u00e1y VLF n\u00e0y c\u00f3 k\u00edch th\u01b0\u1edbc b\u1eb1ng m\u1ed9t chi\u1ebfc vali l\u1edbn. Hai k\u1ef9 s\u01b0 \u0111\u00e3 \u0111\u1eb7t n\u00f3 v\u00e0o ph\u00eda sau m\u1ed9t chi\u1ebfc xe jeep nh\u1ecf. H\u1ecd l\u00e1i xe l\u00ean n\u00fai. Hai ng\u01b0\u1eddi \u0111\u00e0n \u00f4ng mang m\u00e1y \u0111\u1ebfn ch\u1ed7 s\u1ee3i c\u00e1p. H\u1ecd ho\u00e0n th\u00e0nh c\u00f4ng vi\u1ec7c trong v\u00f2ng m\u1ed9t gi\u1edd.<\/p>

\"\"<\/figure>

T\u1ea1i sao kh\u00f4ng ph\u1ea3i l\u00e0 t\u1ea7n s\u1ed1 cao?<\/h3>

M\u1ed9t s\u1ed1 ng\u01b0\u1eddi th\u1eafc m\u1eafc v\u1ec1 t\u1ea7n s\u1ed1 cao. N\u1ebfu t\u1ea7n s\u1ed1 60 Hz \u0111\u00e3 c\u1ea7n m\u1ed9t thi\u1ebft b\u1ecb c\u00f3 k\u00edch th\u01b0\u1edbc b\u1eb1ng m\u1ed9t chi\u1ebfc xe t\u1ea3i, th\u00ec h\u00e3y t\u01b0\u1edfng t\u01b0\u1ee3ng t\u1ea7n s\u1ed1 cao nh\u01b0 1000 Hz s\u1ebd ra sao. Thi\u1ebft b\u1ecb \u0111\u00f3 s\u1ebd ph\u1ea3i c\u00f3 k\u00edch th\u01b0\u1edbc b\u1eb1ng c\u1ea3 m\u1ed9t nh\u00e0 m\u00e1y \u0111i\u1ec7n. V\u1ec1 m\u1eb7t v\u1eadt l\u00fd, vi\u1ec7c ki\u1ec3m tra c\u00e1c d\u00e2y c\u00e1p d\u00e0i b\u1eb1ng t\u1ea7n s\u1ed1 cao t\u1ea1i hi\u1ec7n tr\u01b0\u1eddng l\u00e0 \u0111i\u1ec1u kh\u00f4ng th\u1ec3. D\u01b0\u1edbi \u0111\u00e2y l\u00e0 m\u1ed9t b\u1ea3ng \u0111\u01a1n gi\u1ea3n \u0111\u1ec3 minh h\u1ecda t\u1ea1i sao 0,1 Hz l\u00e0 l\u1ef1a ch\u1ecdn duy nh\u1ea5t th\u1ef1c t\u1ebf.<\/p>

Lo\u1ea1i t\u1ea7n s\u1ed1<\/th>V\u00ed d\u1ee5<\/th>K\u00edch th\u01b0\u1edbc m\u00e1y<\/th>Ch\u00fang ta c\u00f3 th\u1ec3 di chuy\u1ec3n n\u00f3 m\u1ed9t c\u00e1ch d\u1ec5 d\u00e0ng kh\u00f4ng?<\/th><\/tr><\/thead>
T\u1ea7n s\u1ed1 cao<\/strong><\/td>1000 Hz<\/td>Quy m\u00f4 c\u1ee7a m\u1ed9t t\u00f2a nh\u00e0<\/td>Kh\u00f4ng. Kh\u00f4ng th\u1ec3 n\u00e0o.<\/td><\/tr>
M\u1ea1ng l\u01b0\u1edbi \u0111i\u1ec7n xoay chi\u1ec1u th\u00f4ng th\u01b0\u1eddng<\/strong><\/td>50 Hz \/ 60 Hz<\/td>K\u00edch th\u01b0\u1edbc c\u1ee7a m\u1ed9t chi\u1ebfc xe t\u1ea3i l\u1edbn<\/td>R\u1ea5t n\u1eb7ng. C\u1ea7n d\u00f9ng c\u1ea7n c\u1ea9u.<\/td><\/tr>
T\u1ea7n s\u1ed1 c\u1ef1c th\u1ea5p<\/strong><\/td>0,1 Hz<\/td>K\u00edch th\u01b0\u1edbc c\u1ee7a m\u1ed9t chi\u1ebfc vali<\/td>\u0110\u00fang v\u1eady. Hai ng\u01b0\u1eddi \u0111\u00e0n \u00f4ng c\u00f3 th\u1ec3 khi\u00eang \u0111\u01b0\u1ee3c n\u00f3.<\/td><\/tr><\/tbody><\/table><\/figure>

V\u1edbi t\u1ea7n s\u1ed1 0,1 Hz, c\u00e1c thi\u1ebft b\u1ecb ki\u1ec3m tra c\u1ee7a ch\u00fang t\u00f4i mang \u0111\u1ebfn cho b\u1ea1n ch\u1ea5t l\u01b0\u1ee3ng ki\u1ec3m tra d\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u ho\u00e0n to\u00e0n t\u01b0\u01a1ng \u0111\u01b0\u01a1ng. Tuy nhi\u00ean, ch\u00fang l\u1ea1i c\u00f3 k\u00edch th\u01b0\u1edbc nh\u1ecf g\u1ecdn, v\u1eeba v\u1eb7n trong m\u1ed9t chi\u1ebfc h\u1ed9p nh\u1ecf. \u0110i\u1ec1u n\u00e0y gi\u00fap vi\u1ec7c ki\u1ec3m tra t\u1ea1i hi\u1ec7n tr\u01b0\u1eddng tr\u1edf n\u00ean nhanh ch\u00f3ng, ti\u1ebft ki\u1ec7m chi ph\u00ed v\u00e0 c\u00f3 th\u1ec3 th\u1ef1c hi\u1ec7n \u1edf b\u1ea5t k\u1ef3 \u0111\u00e2u tr\u00ean th\u1ebf gi\u1edbi.<\/p>

M\u00e1y ki\u1ec3m tra c\u00e1p VLF c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng t\u1ea7n s\u1ed1 0,1 Hz hay 0,01 Hz kh\u00f4ng?<\/h2>

Ch\u1ecdn t\u1ea7n s\u1ed1 kh\u00f4ng ph\u00f9 h\u1ee3p s\u1ebd khi\u1ebfn b\u1ea1n l\u00e3ng ph\u00ed c\u1ea3 ng\u00e0y. M\u1ed9t cu\u1ed9c th\u1eed nghi\u1ec7m di\u1ec5n ra ch\u1eadm ch\u1ea1p s\u1ebd khi\u1ebfn b\u1ea1n t\u1ed1n c\u1ea3 ti\u1ec1n l\u1eabn th\u1eddi gian. Hi\u1ec3u r\u00f5 s\u1ef1 kh\u00e1c bi\u1ec7t gi\u1eefa 0,1 Hz v\u00e0 0,01 Hz s\u1ebd gi\u00fap b\u1ea1n ti\u1ebft ki\u1ec7m \u0111\u01b0\u1ee3c h\u00e0ng gi\u1edd l\u00e0m vi\u1ec7c.\u00a0\u0110\u00fang v\u1eady, b\u1ea1n c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng t\u1ea7n s\u1ed1 0,01 Hz n\u1ebfu d\u00e2y c\u00e1p c\u1ee7a b\u1ea1n r\u1ea5t d\u00e0i. Tuy nhi\u00ean, m\u1ed9t b\u00e0i ki\u1ec3m tra \u1edf t\u1ea7n s\u1ed1 0,01 Hz s\u1ebd m\u1ea5t nhi\u1ec1u th\u1eddi gian h\u01a1n so v\u1edbi b\u00e0i ki\u1ec3m tra \u1edf t\u1ea7n s\u1ed1 0,1 Hz. B\u1ea1n ch\u1ec9 n\u00ean s\u1eed d\u1ee5ng t\u1ea7n s\u1ed1 0,01 Hz khi d\u00e2y c\u00e1p d\u00e0i khi\u1ebfn m\u00e1y v\u01b0\u1ee3t qu\u00e1 gi\u1edbi h\u1ea1n c\u00f4ng su\u1ea5t \u1edf t\u1ea7n s\u1ed1 0,1 Hz.<\/strong>\u00a0\u00a0<\/p>

Khi b\u1ea1n nh\u00ecn v\u00e0o m\u00e0n h\u00ecnh c\u1ee7a m\u1ed9t KV HIPOT<\/strong> Khi s\u1eed d\u1ee5ng m\u00e1y ki\u1ec3m tra VLF, b\u1ea1n s\u1ebd th\u1ea5y c\u00e1c t\u00f9y ch\u1ecdn t\u1ea7n s\u1ed1 kh\u00e1c nhau. Th\u00f4ng th\u01b0\u1eddng, b\u1ea1n s\u1ebd th\u1ea5y c\u00e1c gi\u00e1 tr\u1ecb 0,1 Hz, 0,05 Hz, 0,02 Hz v\u00e0 0,01 Hz. Nhi\u1ec1u k\u1ef9 s\u01b0 kh\u00f4ng bi\u1ebft n\u00ean ch\u1ecdn gi\u00e1 tr\u1ecb n\u00e0o. H\u1ecd cho r\u1eb1ng t\u1ea5t c\u1ea3 c\u00e1c gi\u00e1 tr\u1ecb n\u00e0y \u0111\u1ec1u cho k\u1ebft qu\u1ea3 gi\u1ed1ng nhau. \u0110\u00e2y l\u00e0 m\u1ed9t sai l\u1ea7m l\u1edbn. Ti\u00eau chu\u1ea9n qu\u1ed1c t\u1ebf cho th\u1eed nghi\u1ec7m VLF l\u00e0 0,1 Hz. B\u1ea1n n\u00ean lu\u00f4n c\u1ed1 g\u1eafng s\u1eed d\u1ee5ng t\u1ea7n s\u1ed1 0,1 Hz tr\u01b0\u1edbc ti\u00ean. Tuy nhi\u00ean, \u0111\u00f4i khi b\u1ea1n kh\u00f4ng th\u1ec3 s\u1eed d\u1ee5ng t\u1ea7n s\u1ed1 n\u00e0y.<\/p>

Gi\u1edbi h\u1ea1n c\u1ee7a m\u00e1y m\u00f3c<\/h3>

M\u1ed7i m\u00e1y ki\u1ec3m tra \u0111\u1ec1u c\u00f3 gi\u1edbi h\u1ea1n. Gi\u1edbi h\u1ea1n n\u00e0y ph\u1ee5 thu\u1ed9c v\u00e0o chi\u1ec1u d\u00e0i c\u00e1p. Ch\u00fang t\u00f4i \u0111o chi\u1ec1u d\u00e0i n\u00e0y d\u01b0\u1edbi d\u1ea1ng \u201c\u0111i\u1ec7n dung\u201d. M\u1ed9t s\u1ee3i c\u00e1p r\u1ea5t d\u00e0i s\u1ebd c\u00f3 \u0111i\u1ec7n dung r\u1ea5t cao. N\u1ebfu b\u1ea1n k\u1ebft n\u1ed1i m\u00e1y ki\u1ec3m tra VLF v\u1edbi m\u1ed9t s\u1ee3i c\u00e1p d\u00e0i 15 kil\u00f4m\u00e9t v\u00e0 nh\u1ea5n n\u00fat kh\u1edfi \u0111\u1ed9ng \u1edf t\u1ea7n s\u1ed1 0,1 Hz, m\u00e1y c\u00f3 th\u1ec3 ph\u00e1t ra ti\u1ebfng b\u00edp. M\u00e0n h\u00ecnh c\u00f3 th\u1ec3 hi\u1ec3n th\u1ecb \u201cQu\u00e1 t\u1ea3i\u201d ho\u1eb7c \u201c\u0110i\u1ec7n dung qu\u00e1 cao\u201d. M\u00e1y kh\u00f4ng c\u00f3 \u0111\u1ee7 c\u00f4ng su\u1ea5t \u0111\u1ec3 \u0111\u1ea9y \u0111i\u1ec7n \u00e1p 0,1 l\u1ea7n m\u1ed7i gi\u00e2y v\u00e0o m\u1ed9t s\u1ee3i c\u00e1p kh\u1ed5ng l\u1ed3 nh\u01b0 v\u1eady. \u0110\u00e2y l\u00e0 l\u00fd do t\u1ea1i sao ch\u00fang t\u00f4i cung c\u1ea5p cho b\u1ea1n t\u00f9y ch\u1ecdn thay \u0111\u1ed5i t\u1ea7n s\u1ed1 xu\u1ed1ng 0,01 Hz. N\u1ebfu b\u1ea1n gi\u1ea3m t\u1ea7n s\u1ed1 xu\u1ed1ng c\u00f2n m\u1ed9t ph\u1ea7n m\u01b0\u1eddi, m\u00e1y s\u1ebd ch\u1ec9 c\u1ea7n m\u1ed9t ph\u1ea7n m\u01b0\u1eddi c\u00f4ng su\u1ea5t. L\u00fac n\u00e0y, m\u00e1y c\u00f3 th\u1ec3 ki\u1ec3m tra d\u1ec5 d\u00e0ng \u0111o\u1ea1n c\u00e1p d\u00e0i 20 km \u0111\u00f3.<\/p>

V\u1ea5n \u0111\u1ec1 ti\u1ec1m \u1ea9n v\u1edbi t\u1ea7n s\u1ed1 0,01 Hz<\/h3>

N\u1ebfu t\u1ea7n s\u1ed1 0,01 Hz gi\u00fap m\u00e1y ho\u1ea1t \u0111\u1ed9ng m\u1ea1nh m\u1ebd h\u01a1n, t\u1ea1i sao ch\u00fang ta kh\u00f4ng s\u1eed d\u1ee5ng n\u00f3 m\u1ecdi l\u00fac? C\u00e2u tr\u1ea3 l\u1eddi l\u00e0 th\u1eddi gian. C\u00f4ng ngh\u1ec7 VLF s\u1eed d\u1ee5ng d\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u. \u0110i\u1ec7n \u00e1p dao \u0111\u1ed9ng l\u00ean xu\u1ed1ng. \u0110i\u1ec1u n\u00e0y t\u1ea1o ra m\u1ed9t s\u00f3ng. \u1ede t\u1ea7n s\u1ed1 0,1 Hz, m\u1ed9t chu k\u1ef3 s\u00f3ng ho\u00e0n ch\u1ec9nh m\u1ea5t 10 gi\u00e2y. Trong m\u1ed9t th\u1eed nghi\u1ec7m th\u00f4ng th\u01b0\u1eddng k\u00e9o d\u00e0i 30 ph\u00fat, d\u00e2y c\u00e1p ch\u1ec9 nh\u1eadn \u0111\u01b0\u1ee3c 180 chu k\u1ef3 s\u00f3ng. S\u1ed1 l\u01b0\u1ee3ng n\u00e0y \u0111\u1ee7 \u0111\u1ec3 ph\u00e1t hi\u1ec7n \u0111i\u1ec3m y\u1ebfu. \u1ede t\u1ea7n s\u1ed1 0,01 Hz, s\u00f3ng r\u1ea5t ch\u1eadm. M\u1ed9t chu k\u1ef3 s\u00f3ng ho\u00e0n ch\u1ec9nh m\u1ea5t 100 gi\u00e2y. Trong m\u1ed9t cu\u1ed9c ki\u1ec3m tra k\u00e9o d\u00e0i 30 ph\u00fat, d\u00e2y c\u00e1p ch\u1ec9 nh\u1eadn \u0111\u01b0\u1ee3c 18 s\u00f3ng. \u0110\u00e2y l\u00e0 m\u1ed9t con s\u1ed1 r\u1ea5t nh\u1ecf. N\u00f3 c\u00f3 th\u1ec3 kh\u00f4ng \u0111\u1ee7 \u0111\u1ec3 l\u00e0m h\u1ecfng m\u1ed9t m\u1ed1i n\u1ed1i k\u00e9m ch\u1ea5t l\u01b0\u1ee3ng.<\/p>

Tu\u00e2n th\u1ee7 c\u00e1c quy t\u1eafc<\/h3>

Ti\u00eau chu\u1ea9n IEEE 400.2 ch\u1ec9 r\u00f5 ch\u00ednh x\u00e1c nh\u1eefng g\u00ec c\u1ea7n l\u00e0m. N\u1ebfu b\u1ea1n gi\u1ea3m t\u1ea7n s\u1ed1, b\u1ea1n ph\u1ea3i t\u0103ng th\u1eddi gian ki\u1ec3m tra. B\u1ea1n ph\u1ea3i cung c\u1ea5p \u0111\u1ee7 s\u00f3ng cho c\u00e1p \u0111\u1ec3 ph\u00e1t hi\u1ec7n c\u00e1c l\u1ed7i \u1ea9n. N\u1ebfu ki\u1ec3m tra \u1edf t\u1ea7n s\u1ed1 0,1 Hz, b\u1ea1n c\u00f3 th\u1ec3 c\u1ea7n ki\u1ec3m tra trong 30 ph\u00fat. N\u1ebfu chuy\u1ec3n sang 0,05 Hz, b\u1ea1n c\u00f3 th\u1ec3 ph\u1ea3i ki\u1ec3m tra trong 60 ph\u00fat. N\u1ebfu chuy\u1ec3n sang 0,01 Hz, b\u1ea1n c\u00f3 th\u1ec3 ph\u1ea3i ki\u1ec3m tra trong nhi\u1ec1u gi\u1edd.<\/p>

M\u1ed9t c\u00e2u chuy\u1ec7n c\u00f3 th\u1eadt t\u1eeb Nam Phi<\/h3>

T\u00f4i \u0111\u00e3 h\u1ed7 tr\u1ee3 m\u1ed9t nh\u00e0 th\u1ea7u EPC t\u1ea1i Nam Phi. H\u1ecd \u0111ang x\u00e2y d\u1ef1ng m\u1ed9t trang tr\u1ea1i n\u0103ng l\u01b0\u1ee3ng m\u1eb7t tr\u1eddi quy m\u00f4 l\u1edbn. H\u1ecd c\u1ea7n ki\u1ec3m tra m\u1ed9t \u0111\u01b0\u1eddng c\u00e1p \u0111i\u1ec7n ch\u00ednh, d\u00e0i 12 kil\u00f4m\u00e9t. H\u1ecd \u0111\u00e3 k\u1ebft n\u1ed1i m\u00e1y ki\u1ec3m tra VLF v\u00e0 c\u00e0i \u0111\u1eb7t t\u1ea7n s\u1ed1 \u1edf m\u1ee9c 0,1 Hz. Thi\u1ebft b\u1ecb hi\u1ec3n th\u1ecb l\u1ed7i qu\u00e1 t\u1ea3i. H\u1ecd \u0111\u00e3 nh\u1eafn tin cho t\u00f4i qua WhatsApp v\u00e0 t\u1ecf ra r\u1ea5t lo l\u1eafng. Ng\u01b0\u1eddi thanh tra \u0111ang ch\u1edd. T\u00f4i b\u1ea3o h\u1ecd chuy\u1ec3n t\u1ea7n s\u1ed1 xu\u1ed1ng 0,05 Hz. H\u1ecd th\u1eed l\u00e0m theo. M\u00e1y v\u1eabn b\u00e1o l\u1ed7i. C\u00e1p qu\u00e1 l\u1edbn. T\u00f4i b\u1ea3o h\u1ecd chuy\u1ec3n xu\u1ed1ng 0,02 Hz. H\u1ecd nh\u1ea5n n\u00fat kh\u1edfi \u0111\u1ed9ng. M\u00e1y ho\u1ea1t \u0111\u1ed9ng ho\u00e0n h\u1ea3o. \u0110i\u1ec7n \u00e1p t\u0103ng l\u00ean. Nh\u01b0ng t\u00f4i \u0111\u00e3 c\u1ea3nh b\u00e1o h\u1ecd. T\u00f4i n\u00f3i: \u201cB\u00e2y gi\u1edd c\u00e1c b\u1ea1n kh\u00f4ng th\u1ec3 th\u1ef1c hi\u1ec7n b\u00e0i ki\u1ec3m tra 15 ph\u00fat \u0111\u01b0\u1ee3c. T\u1ea7n s\u1ed1 qu\u00e1 ch\u1eadm. C\u00e1c b\u1ea1n ph\u1ea3i ch\u1ea1y b\u00e0i ki\u1ec3m tra trong th\u1eddi gian d\u00e0i h\u01a1n.\u201d H\u1ecd b\u00e1o l\u1ea1i v\u1edbi thanh tra vi\u00ean. Thanh tra vi\u00ean \u0111\u1ed3ng \u00fd. H\u1ecd ch\u1ea1y b\u00e0i ki\u1ec3m tra trong th\u1eddi gian d\u00e0i h\u01a1n. D\u00e2y c\u00e1p \u0111\u00e3 \u0111\u1ea1t ti\u00eau chu\u1ea9n. H\u1ecd nh\u1eadn \u0111\u01b0\u1ee3c ti\u1ec1n thanh to\u00e1n. D\u01b0\u1edbi \u0111\u00e2y l\u00e0 m\u1ed9t b\u1ea3ng \u0111\u01a1n gi\u1ea3n \u0111\u1ec3 gi\u00fap b\u1ea1n ch\u1ecdn t\u1ea7n s\u1ed1 ph\u00f9 h\u1ee3p t\u1ea1i hi\u1ec7n tr\u01b0\u1eddng.<\/p>

C\u00e0i \u0111\u1eb7t t\u1ea7n s\u1ed1<\/th>\u0110\u00e3 \u0111\u1ebfn l\u00fac cho \"One Wave\"<\/th>Ph\u00f9 h\u1ee3p nh\u1ea5t \u0111\u1ec3 s\u1eed d\u1ee5ng cho<\/th>C\u1ea3nh b\u00e1o<\/th><\/tr><\/thead>
0,1 Hz<\/strong><\/td>10 gi\u00e2y<\/td>C\u00e1p th\u00f4ng th\u01b0\u1eddng. C\u00e1p ng\u1eafn. Th\u1eed nghi\u1ec7m ti\u00eau chu\u1ea9n.<\/td>H\u00e3y lu\u00f4n th\u1eed c\u00e1ch n\u00e0y tr\u01b0\u1edbc ti\u00ean.<\/td><\/tr>
0,05 Hz<\/strong><\/td>20 gi\u00e2y<\/td>C\u00e1p c\u00f3 \u0111\u1ed9 d\u00e0i trung b\u00ecnh \u0111\u1ebfn d\u00e0i.<\/td>M\u1ea5t nhi\u1ec1u th\u1eddi gian h\u01a1n \u0111\u1ec3 ho\u00e0n th\u00e0nh b\u00e0i ki\u1ec3m tra.<\/td><\/tr>
0,02 Hz<\/strong><\/td>50 gi\u00e2y<\/td>C\u00e1c s\u1ee3i c\u00e1p r\u1ea5t d\u00e0i.<\/td>C\u1ea7n th\u1eddi gian th\u1eed nghi\u1ec7m l\u00e2u h\u01a1n nhi\u1ec1u.<\/td><\/tr>
0,01 Hz<\/strong><\/td>100 gi\u00e2y<\/td>C\u00e1c s\u1ee3i c\u00e1p c\u1ef1c k\u1ef3 d\u00e0i.<\/td>Qu\u00e1 tr\u00ecnh ki\u1ec3m tra c\u00f3 th\u1ec3 m\u1ea5t v\u00e0i gi\u1edd. Ch\u1ec9 n\u00ean th\u1ef1c hi\u1ec7n khi c\u1ea7n thi\u1ebft.<\/td><\/tr><\/tbody><\/table><\/figure>

V\u1eady, c\u00f3 \u0111\u01b0\u1ee3c ph\u00e9p s\u1eed d\u1ee5ng t\u1ea7n s\u1ed1 0,01 Hz kh\u00f4ng? C\u00f3. Ho\u00e0n to\u00e0n \u0111\u01b0\u1ee3c. M\u00e1y \u0111\u01b0\u1ee3c thi\u1ebft k\u1ebf \u0111\u1ec3 th\u1ef1c hi\u1ec7n \u0111i\u1ec1u n\u00e0y. Nh\u01b0ng b\u1ea1n ph\u1ea3i nh\u1edb quy t\u1eafc n\u00e0y: t\u1ea7n s\u1ed1 c\u00e0ng th\u1ea5p th\u00ec th\u1eddi gian ki\u1ec3m tra c\u00e0ng ph\u1ea3i d\u00e0i h\u01a1n. Lu\u00f4n b\u1eaft \u0111\u1ea7u v\u1edbi t\u1ea7n s\u1ed1 0,1 Hz. Ch\u1ec9 n\u00ean gi\u1ea3m xu\u1ed1ng m\u1ee9c th\u1ea5p h\u01a1n khi m\u00e1y b\u00e1o r\u1eb1ng d\u00e2y c\u00e1p qu\u00e1 l\u1edbn.<\/p>

K\u1ebft lu\u1eadn<\/h2>

Ki\u1ec3m tra c\u00e1p b\u1eb1ng c\u00f4ng ngh\u1ec7 VLF l\u00e0 m\u1ed9t l\u1ef1a ch\u1ecdn an to\u00e0n v\u00e0 th\u00f4ng minh cho h\u1ec7 th\u1ed1ng c\u00e1p c\u1ee7a b\u1ea1n. B\u1eb1ng c\u00e1ch ch\u1ecdn t\u1ea7n s\u1ed1 ph\u00f9 h\u1ee3p, b\u1ea1n c\u00f3 th\u1ec3 d\u1ec5 d\u00e0ng ph\u00e1t hi\u1ec7n c\u00e1c khuy\u1ebft t\u1eadt ti\u1ec1m \u1ea9n v\u00e0 \u0111\u1ea3m b\u1ea3o h\u1ec7 th\u1ed1ng \u0111i\u1ec7n c\u1ee7a b\u1ea1n lu\u00f4n ho\u1ea1t \u0111\u1ed9ng ho\u00e0n h\u1ea3o.<\/p>","protected":false},"excerpt":{"rendered":"

Ki\u1ec3m tra c\u00e1p b\u1eb1ng c\u00f4ng ngh\u1ec7 VLF l\u00e0 m\u1ed9t l\u1ef1a ch\u1ecdn an to\u00e0n v\u00e0 th\u00f4ng minh cho h\u1ec7 th\u1ed1ng c\u00e1p c\u1ee7a b\u1ea1n. B\u1eb1ng c\u00e1ch ch\u1ecdn t\u1ea7n s\u1ed1 ph\u00f9 h\u1ee3p, b\u1ea1n c\u00f3 th\u1ec3 d\u1ec5 d\u00e0ng ph\u00e1t hi\u1ec7n c\u00e1c khuy\u1ebft t\u1eadt ti\u1ec1m \u1ea9n v\u00e0 \u0111\u1ea3m b\u1ea3o h\u1ec7 th\u1ed1ng \u0111i\u1ec7n c\u1ee7a b\u1ea1n lu\u00f4n ho\u1ea1t \u0111\u1ed9ng ho\u00e0n h\u1ea3o.<\/p>","protected":false},"author":1,"featured_media":5754,"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":[35],"tags":[],"_links":{"self":[{"href":"https:\/\/kvhipot.com\/vi\/wp-json\/wp\/v2\/posts\/6420"}],"collection":[{"href":"https:\/\/kvhipot.com\/vi\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kvhipot.com\/vi\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kvhipot.com\/vi\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/kvhipot.com\/vi\/wp-json\/wp\/v2\/comments?post=6420"}],"version-history":[{"count":1,"href":"https:\/\/kvhipot.com\/vi\/wp-json\/wp\/v2\/posts\/6420\/revisions"}],"predecessor-version":[{"id":6423,"href":"https:\/\/kvhipot.com\/vi\/wp-json\/wp\/v2\/posts\/6420\/revisions\/6423"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/kvhipot.com\/vi\/wp-json\/wp\/v2\/media\/5754"}],"wp:attachment":[{"href":"https:\/\/kvhipot.com\/vi\/wp-json\/wp\/v2\/media?parent=6420"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kvhipot.com\/vi\/wp-json\/wp\/v2\/categories?post=6420"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kvhipot.com\/vi\/wp-json\/wp\/v2\/tags?post=6420"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}