Thytronic NA20, Manual, Page: 6 / 208

INTRODUCTION
6 NA20 - Manual - 04 - 2022
Product identification
Each device is equipped with:
• Identification label installed on the front side with following informations: code number, phase and
residual nominal currents, auxiliary voltage range and CE mark:
• Test label with following informations: data, serial number and test operator signature.
Environment
The NA20 device must be employed according to the environment conditions shown (see technical
data).
In case of different environment conditions, appropriate provisions must be provided (conditioning
system, humidity control, etc...).
If contaminants are present (dust, corrosive substances, etc...), filters must be provided.
Graphical conventions
The CEI/IEC and ANSI symbols is employed where possible:
e.g.: 51 = ANSI code concerning the overcurrent element.
Following text formats are used:
The ThyVisor
[1]
menu:
Phase overcurrent -50/51
The parameter description (measures, thresholds, operate time,...) and related value:
I> element
Definite time
I>def
The display messages (MMI) are shown as:
NA20
Notes are highlighted with cursive letters inside colored bar
Note: Useful description note
Glossary/definitions
I
En
Relay residual nominal current
I
Enp
Residual CT primary nominal current
I
n
Relay phase nominal current
I
np
Phase CT primary nominal current
I
B
Basic current: it represents the nominal current of the line or trans-
former, referred to the nominal current of the CT’s for thermal image
protection
37 Undercurrent ANSI code
46 Negative sequence overcurrent ANSI code
49 Thermal image ANSI code
50/51 Phase overcurrent ANSI code
50N/51N Residual overcurrent ANSI code
BF Circuit breaker failure ANSI code
74CT CT supervision
74TCS Trip Circuit Supervision
DFR Digital Fault Recorder (Oscillography)
SER Sequential Event Recorder
SFR Sequential Fault Recorder
ANSI American National Standard Institute
IEEE Institute of Electrical and Electronics Engineers
IEC International Electrotechnical Commission
CENELEC Comité Européen de Normalisation Electrotechnique
52 o CB (Circuit Breaker) Circuit Breaker
52a Auxiliary contact in the breaker that is in the same position as the
breaker. It can be assigned to a binary input to locate the CB position
(Breaker failure and/or CB diagnostic functions). (52a open = CB open)
52b Auxiliary contact in the breaker that is in the opposite position as the
breaker (52b open = CB closed)
K1...K6...K10 Output relays
Pulse Output relay with pulse operation
tTR Output relay minimum pulse width
Latched Output relay with latched operation (manual reset) Output relay with
latched operation (automatic reset)
No-latched Output relay with no-latched operation (automatic reset)
CT Current Transformer
P1 IEC nomenclature for primary polarity mark of CTs (as an alternative to
a ANSI dot)
P2 IEC nomenclature for primary polarity mark of CTs (as an alternative to
Note 1 The graphic interface and the operation of the ThyVisor software are described in the relative chapters