Scribd
Upload
68 views1 page

2.4 The Surge Protection Device (SPD) : Principle

The document discusses surge protection devices (SPDs) which are used to protect electrical power supply networks, telephone networks, and communication and automatic control buses from overvoltage. SPDs are connected in parallel on the power supply circuit of loads to protect them. When a transient overvoltage occurs, the impedance of the SPD decreases so surge current is driven through it, bypassing sensitive equipment.

Uploaded by

mahmoud12122012
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
68 views1 page

2.4 The Surge Protection Device (SPD) : Principle

The document discusses surge protection devices (SPDs) which are used to protect electrical power supply networks, telephone networks, and communication and automatic control buses from overvoltage. SPDs are connected in parallel on the power supply circuit of loads to protect them. When a transient overvoltage occurs, the impedance of the SPD decreases so surge current is driven through it, bypassing sensitive equipment.

Uploaded by

mahmoud12122012
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
You are on page 1/ 1

J - Overvoltage protection

6XUJH3URWHFWLRQ'HYLFHV 63' DUHXVHGIRU 2.4 The Surge Protection Device (SPD)


HOHFWULFSRZHUVXSSO\QHWZRUNVWHOHSKRQH
7KH6XUJH3URWHFWLRQ'HYLFH 63' LVDFRPSRQHQWRIWKHHOHFWULFDOLQVWDOODWLRQ
QHWZRUNVDQGFRPPXQLFDWLRQDQGDXWRPDWLF
SURWHFWLRQV\VWHP
FRQWUROEXVHV 7KLVGHYLFHLVFRQQHFWHGLQSDUDOOHORQWKHSRZHUVXSSO\FLUFXLWRIWKHORDGVWKDWLW
KDVWRSURWHFW VHHFig. J17 ,WFDQDOVREHXVHGDWDOOOHYHOVRIWKHSRZHUVXSSO\
QHWZRUN
7KLVLVWKHPRVWFRPPRQO\XVHGDQGPRVWHI¿FLHQWW\SHRIRYHUYROWDJHSURWHFWLRQ

63'FRQQHFWHGLQSDUDOOHOKDVDKLJKLPSHGDQFH
Once the transient overvoltage appears in the ,QFRPLQJ
V\VWHPWKHLPSHGDQFHRIWKHGHYLFHGHFUHDVHV FLUFXLWEUHDNHU
VRVXUJHFXUUHQWLVGULYHQWKURXJKWKH63'
E\SDVVLQJWKHVHQVLWLYHHTXLSPHQW

/LJKWQLQJ 63'
FXUUHQW

6HQVLWLYHORDGV

Fig. J17 3ULQFLSOHRISURWHFWLRQV\VWHPLQSDUDOOHO

J10 Principle
63'LVGHVLJQHGWROLPLWWUDQVLHQWRYHUYROWDJHVRIDWPRVSKHULFRULJLQDQGGLYHUW
FXUUHQWZDYHVWRHDUWKVRDVWROLPLWWKHDPSOLWXGHRIWKLVRYHUYROWDJHWRDYDOXHWKDW
LVQRWKD]DUGRXVIRUWKHHOHFWULFDOLQVWDOODWLRQDQGHOHFWULFVZLWFKJHDUDQGFRQWUROJHDU
SPD eliminates overvoltages:
bLQFRPPRQPRGHEHWZHHQSKDVHDQGQHXWUDORUHDUWK
bLQGLIIHUHQWLDOPRGHEHWZHHQSKDVHDQGQHXWUDO
,QWKHHYHQWRIDQRYHUYROWDJHH[FHHGLQJWKHRSHUDWLQJWKUHVKROGWKH63'
bFRQGXFWVWKHHQHUJ\WRHDUWKLQFRPPRQPRGH
bGLVWULEXWHVWKHHQHUJ\WRWKHRWKHUOLYHFRQGXFWRUVLQGLIIHUHQWLDOPRGH
The three types of SPD:
b Type 1 SPD
7KH7\SH63'LVUHFRPPHQGHGLQWKHVSHFL¿FFDVHRIVHUYLFHVHFWRUDQGLQGXVWULDO
EXLOGLQJVSURWHFWHGE\DOLJKWQLQJSURWHFWLRQV\VWHPRUDPHVKHGFDJH
,WSURWHFWVHOHFWULFDOLQVWDOODWLRQVDJDLQVWGLUHFWOLJKWQLQJVWURNHV,WFDQGLVFKDUJH
WKHEDFNFXUUHQWIURPOLJKWQLQJVSUHDGLQJIURPWKHHDUWKFRQGXFWRUWRWKHQHWZRUN
FRQGXFWRUV
7\SH63'LVFKDUDFWHUL]HGE\D—VFXUUHQWZDYH
b Type 2 SPD
7KH7\SH63'LVWKHPDLQSURWHFWLRQV\VWHPIRUDOOORZYROWDJHHOHFWULFDO
LQVWDOODWLRQV,QVWDOOHGLQHDFKHOHFWULFDOVZLWFKERDUGLWSUHYHQWVWKHVSUHDGRI
RYHUYROWDJHVLQWKHHOHFWULFDOLQVWDOODWLRQVDQGSURWHFWVWKHORDGV
7\SH63'LVFKDUDFWHUL]HGE\DQ—VFXUUHQWZDYH
b Type 3 SPD
7KHVH63'VKDYHDORZGLVFKDUJHFDSDFLW\7KH\PXVWWKHUHIRUHPDQGDWRULO\EH
LQVWDOOHGDVDVXSSOHPHQWWR7\SH63'DQGLQWKHYLFLQLW\RIVHQVLWLYHORDGV
7\SH63'LVFKDUDFWHUL]HGE\DFRPELQDWLRQRIYROWDJHZDYHV ȝV DQG
FXUUHQWZDYHV ȝV 
© Schneider Electric - all rights reserved

You might also like