安规网

标题: PDSH 1021 Short circuit and overload protection [打印本页]
作者: 小米    时间: 2012-11-8 15:17
标题: PDSH 1021 Short circuit and overload protection
PDSH 1021+ a' s$ L& @8 e% C7 L( I
1 W8 m+ A/ Y2 O2 ~" ], M  M
Short circuit and overload protection
4 h; M2 V) z4 ?, c7 }		15.2
# l+ `2 E) ^% r* |# c4 |( B		61558-1(ed.1);am1 & 61558-1(ed.2);am1
* s: U4 O) I: t( _+ P/ E$ P, s
4 Y' `# m+ y4 _
Standard(s):/ f. X$ x9 z( d! ~, z
IEC 61558-1
* c- l( I( u# pAll editions
  [" l. `' V/ r6 E* @Subclause(s):, E) d; }. v6 C2 b: w6 D
15.2
, T' j* I2 |+ Z' ?' x1 V. |( `; C( GNo. Year
& l, [$ i: \, e+ x3 n) K, n# S, T0 VPDSH
/ d7 r+ R7 g0 M- P7 T1021 2010
! P" K  [8 e) ECategory: SAFE Developed by: ETF5
9 s$ Q$ D8 e& h( _7 w) qOSM/LUM' @& ]) O( j5 a/ u: [. X
Subject:+ N8 w* L$ s2 W
Short circuit and overload" M$ H; d, Z2 E$ J" J
protection5 X8 m, i- u: }* T
Key words:
' M+ z, h8 b) V# o; ~- Transformers
8 X% l: t+ d" ^- Steady state conditions
. ^- _$ N2 L0 g5 ~- Short circuit; i' P& ]* @: B1 j1 M0 A9 P8 D
To be approved at the 49th
! T; S+ v- U+ J% w2 |4 L/ L* OCTL Plenary Meeting, in 20125 B+ D- A/ d0 S% G1 ]
Question:9 @8 T. h% j% n/ N, h( {
Inherently short-circuit proof transformers shall be tested by short-circuiting the output windings until/ d1 I& c5 S- M& e4 i) j
steady-state conditions are reached./ U% L. I7 n; J4 @  n
In the IEC 61558-1 “steady-state condition” is not explained. Referring to other standards for the meaning
; _& z- D9 p! s* U6 W* E% Z, ~of “steady-state conditions”. Or “thermal stability”. The thermal stability is the change of temperature of
) j/ m! q& X4 k3 k4 Z, D, Nless than 1°C per hour. So the following questions arise:2 F% b: ?' b9 V! S8 d; ]- G% a
Is it correct to record the temperatures after one hour when temperatures didn’t change (more than 1°C/h)?/ Z; j% u& s, ]
How shall an inherently short-circuit proof transformer be assessed when the above mentioned
' ~) ^% m' ]' J" d0 Lrequirements are fulfilled, but the transformer is damaged 6h, after reaching the steady state condition, in
% q* }% h4 y0 k' }" B& x7 ba way where safety will be impaired (the transformer bursts).
' E! \* G- p2 Z* C5 T! Z2 {Decision:
' u0 h& r, \2 @Yes. The transformer should not be accepted because the insulated materials are not corresponding to the
  l2 v# y! p8 I( Qinsulation class of the transformer.6 X( k* A2 i1 t* g6 t

: D6 h' Y* I: U4 t5 }[attach]77268[/attach]! @" U( G' U/ @4 z




欢迎光临 安规网 (http://bbs1.angui.org/) Powered by Discuz! X3.2