|
引用第1楼yanfenghmm于2010-01-06 09:17发表的 :: m$ g( n8 l* r
标准应该有具体要求吧。 文字的要求有时是含混不清的,要看读者的理解呀4 ]6 M& U3 c N% R @) s" J
下面是table 4:5 k2 b+ e; n% Q4 \, `# e
.
% ~0 B8 H. U6 D! Z; C* M9 d; c/ Z! G* S! Z( k1 J
6.7.1.1 CLEARANCES
9 i+ u& ~& D$ X( T1 w3 {CLEARANCES are specified to withstand the maximum transient overvoltage that can be6 ]+ [5 s- E3 Y+ P: `
present on the circuit, either as a result of an external event (such as a lightning strike, or a0 e! I) |" ]+ J9 ^
switching transient), or as the result of the operation of the equipment. If transient
: N. {* ]5 e1 Kovervoltages cannot occur, CLEARANCES are based on the maximum WORKING VOLTAGE.% F1 H) T& M2 t9 g, M, f+ n
The value for CLEARANCE depends on
8 Y' d c8 m" la) the type of insulation (basic insulation, reinforced insulation, etc.);& O) E% Y7 k$ J0 m5 Q1 K
b) the POLLUTION degree of the micro-environment of the CLEARANCE.# p7 Y3 ?. G4 X8 s
9 O4 A. {0 P; ^8 Q6.7.1.2 CREEPAGE DISTANCES2 O" {5 S. E' ]9 x
For CREEPAGE DISTANCES between two circuits, the actual WORKING VOLTAGE which stresses
3 u" m/ i+ b- O6 Vthe insulation between the circuits shall be used. Linear interpolation of CREEPAGE DISTANCE is4 I" g1 Z# F' t4 F) p
permissible. CREEPAGE DISTANCE shall always be at least as large as the value specified for
) f/ U1 n% \9 z$ Q M8 N" BCLEARANCE.6 f% X* Z2 K K4 T) x
& z6 b8 J9 F! P1 ]9 r一般而言电气间隙被设计为耐受最高瞬时过电压,经常会考虑工作电压峰值带来的影响;而爬电距离被认为是耐受工作电压有效值的。
( z4 ], W& q9 h9 d) \从上面两大块文字中,该标准中6.7.1.1看不出电气间隙要考虑工作电压(peak or rms)的要求,但6.7.1.2爬电距离明确说明要考虑工作电压。而table 4中第一列表头只写了"Voltage line-toneutral
3 Z7 g; q) }% W2 Sa.c. r.m.s. or d.c.",也没有提"working voltage"。所以实际查表时我就犯难了,到底如何操作呢,请高手指教! |
本帖子中包含更多资源
您需要 登录 才可以下载或查看,没有帐号?注册安规
x
|