Protection Settings
41
TemBreak
PRO
P_SE-UM-001-EN
– V1.2.0
Thermal Self-Protection
Thermal self-protection is enabled automatically where STD is disabled. This is to ensure that the continuation of the LTD curve does not intersect with the
Critical Area of the MCCB, which could create overheating stresses in the MCCB and cause irreparable damage and/or undesirable operation or failure of
the trip-unit.
To achieve this, a supplementary I²t = K curve is added to the end of LTD tripping curve, starting from I
tsp
, where constant K = Max(I
i
)² x t
tsp
. Max(I
i
) is the
maximum I
i
settable on the trip unit and is not adjustable.
Thermal self-protection is only on the following MCCBs. When activated, I
tsp
and t
tsp
values are specified as follows:
MCCB
I
tsp
x I
r
t
tsp
(seconds)
P160_SE I
n
= 160A
8
2
P250_SE I
n
= 250A
8
2
Notice
: Thermal self-protection is applied to all phases where LTD protection is enabled.
In the case of 4P MCCBs, Thermal self-protection is also applied to the neutral pole (irrespective of the N
Coefficient parameter) provided that Neutral Protection (NP) is enabled. Refer to
section.
Notice
:
LTD thermal image value θ is only affected during a trip event where it is temporarily forced to a value
over 100%.
Summary of Contents for Terasaki TemBreak PRO P SE Series
Page 106: ...106 TemBreak PRO P_SE UM 001 EN V1 2 0 Annex A Dimensions P160 Dimensions...
Page 107: ...Annex A Dimensions 107 TemBreak PRO P_SE UM 001 EN V1 2 0 P250 Dimensions...
Page 108: ...Annex A Dimensions 108 TemBreak PRO P_SE UM 001 EN V1 2 0 P400 Dimensions...
Page 109: ...Annex A Dimensions 109 TemBreak PRO P_SE UM 001 EN V1 2 0 P630 Dimensions...
Page 111: ...111 TemBreak PRO P_SE UM 001 EN V1 2 0 Annex C I2t Let Through Curves P160_SE...
Page 112: ...Annex C I2t Let Through Curves 112 TemBreak PRO P_SE UM 001 EN V1 2 0 P250_SE...
Page 113: ...Annex C I2t Let Through Curves 113 TemBreak PRO P_SE UM 001 EN V1 2 0 P400_SE...
Page 114: ...Annex C I2t Let Through Curves 114 TemBreak PRO P_SE UM 001 EN V1 2 0 P630_SE...
Page 115: ...115 TemBreak PRO P_SE UM 001 EN V1 2 0 Annex D Peak Let Through Curves P160_SE...
Page 116: ...116 TemBreak PRO P_SE UM 001 EN V1 2 0 P250_SE...
Page 117: ...117 TemBreak PRO P_SE UM 001 EN V1 2 0 P400_SE...
Page 118: ...118 TemBreak PRO P_SE UM 001 EN V1 2 0 P630_SE...
Page 121: ...121 TemBreak PRO P_SE UM 001 EN V1 2 0 This page is intentionally left blank...