Setting Guidelines - ABB REC670 Applications Manual

Section 17
Monitoring
17.11.2
550
Insulation aging or deterioration is a time function of temperature, moisture content,
and oxygen content. With modern oil preservation systems, the moisture and oxygen
contributions to insulation deterioration can be minimized, leaving insulation
temperature as the controlling parameter.
Temperature distribution is not uniform in transformers, the part that is operating at the
highest temperature normally undergoes the greatest deterioration. Therefore, in aging
studies it is usual to consider the aging effects produced by the highest (hottest-spot)
temperature. Since many factors influences the cumulative effect of temperature over
time which causes transformer insulation deterioration, it is difficult to predict the
useful life of the insulation in a transformer with great degree of accuracy. However,
this function will help in reducing the accelerated aging of power transformers during
overload conditions and thus maximize the transformer operating life.

Setting guidelines

The parameters for the estimation of transformer insulation life function LOLSPTR
(26/49HS) are set via the local HMI or PCM600.
Minimum information about the transformer parameters which are required to decide
the transformer insulation life are:
1. Top oil temperature rise over ambient temperature at rated load
2. Average conductor temperature rise over ambient temperature at rated load
3. Winding hot spot temperature rise over ambient temperature
4. Load losses at rated load
5. No-Load (core) loss
6. Oil flow design (Directed or non-directed)
7. Weight of core and coil assembly
8. Weight of tank and fittings
9. Weight of oil in the tank and cooling equipment (excluding load tap changer, oil
expansion tanks)
For information about 1 to 5, the conditions (load, ambient temperature, tap, etc.) under
which the measurements are made should be known. In order to have more precise
calculations, load loss at rated and tap extremes or all possible tap connection
combinations are required.
Operation: Disabled or Enabled.
TrafoRating: Rated transformer power in MVA.
TrafoType: This setting is used to set the number of phases in the transformer. The
options are:
1MRK 511 401-UUS A
GUID-48FC89C4-881E-49F0-AD2A-576D1BDBE9EE v1
GUID-FED52BFB-66A9-46E9-BD11-3FA18DD0FB50 v1
Bay control REC670 2.2 ANSI
Application manual