ABB CA-26 Selebaran Instruksi

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Effective: February 1995

Supersedes I.L. 41-337.31A, Dated February 1983

(

) Denotes Change Since Previous Issue

Before putting relays into service, remove all

blocking which may have been inserted for

the purpose of securing the parts during

shipment, make sure that all moving parts

operate freely, inspect the contacts to see

that they are clean and close properly, and

operate the relay to check the settings and

electrical connections.

1.0

APPLICATION

These relays have been specially designed and

tested to establish their suitability for class 1E appli-

cations. Materials have been selected and tested to

insure that the relays will preform their intended func-

tion for their design life when operated in a normal

environment as defined by ANSI standard C37.90-

1978, when exposed to radiation levels up to 10

rads, and when subjected to seismic events produc-

ing a Shock Response Spectrum within the limits of

the relay rating.

"Class 1E" is the safety classification of the electric

equipment and systems in nuclear power generating

stations that are essential to emergency shutdown of

the reactor, containment isolation, cooling of the reac-

tor, and heat removal from the containment and reac-

tor, or otherwise are essential in preventing significant

release of radioactive material to the environment.

The current transformers should not saturate when

carrying the maximum external fault current. This

requirement is met if the burden impedance does not

exceed

All possible contingencies which may arise during installation, operation or maintenance, and all details and

variations of this equipment do not purport to be covered by these instructions. If further information is desired

by purchaser regarding this particular installation, operation or maintenance of this equipment, the local ABB

Power T&D Company Inc. representative should be contacted.

Printed in U.S.A.

Courtesy of NationalSwitchgear.com

ABB Automation Inc.

Substation Automation and Protection Division

Coral Springs, FL

CAUTION

Type CA-16

Percentage Differential

Relay for Bus Protection

Class 1E Applications

(

–

100

e xt ·

-------------------------------------------------------- -

(

)

1.33 I

ext

= proportion of total ct turns in use

= current transformer accuracy class C

voltage

= maximum external fault current in secondary

ext

RMS amperes. (let I

fault current is less than 100A)

= current transformer secondary finding resis-

tance, ohms

For example, if the 400:5 tap of 800:5 C400 current

transformers are used, N

120A, R

= 1.0 ohm the burden should not exceed:

(

)

–

100R

e xt.

---------------------------------------------------------- - =

(

)

1.33 I

ext.

(

)x1.0

0.5x400

–

120 100

–

---------------------------------------------------------------- -

1.33x120

The CA-16 relay should not be utilized for transformer

differential applications since it is too sensitive for

overriding the inrush. Likewise the CA-26 relay

should not be used for bus protection with the "four

circuit bus" connections of Figure 6.

2.0

CONSTRUCTION

The type CA-16 relay consists of an indicating con-

tactor switch, autotransformer, three restraint ele-

ments, an operating element, and a sensitive fault

detector.

The principal component parts of the relay and their

location are shown in Figures 1 to 3.

Instruction Leaflet

41-337.31B

where

= 100 if max. external

ext.

= 400/800 = 0.50, if I

ext.

1.13 ohms