The winding temperature indicator is a special-purpose instrument using the simulated
temperature measurement technique to measure the temperature of the hottest portion of the
transformer winding,which is obtained as the summation of T0 and △T , or T=T0+△T,where,T0 is
the oil temperature in upper part of the transformer, which can be easily measured; and △T is the
temperature rise caused by the rise of the transformer loading current.
The main functions of the winding temperature indicator model BWR(WTYK)-04 are the
signal alarming, cooling control and accident tripping etc. With its excellent performance of
protection and disturbance rejection, and high reliability, this instrument works well in the outdoor
condition. It can also transfer the winding temperature signal to the control center, display
simultaneously on the computer system and monitor the working conduction of the transformer.
. model description
a) Output signal:
A- Directly output DC (4-20) mA current signal. Output DC (4-20) mA current signal and
DC (0-5) V voltage signal through XMT-288 controller.
V- Directly output DC (0-5) V voltage signal.
RS-Directly output DC (4-20)mA current signal. Output with RS-485 computer
communication port through XMT-288 controller.
Y- Directly output Pt100 platinum resistor signal.
JJ-Directly output double DC (4-20)mA current signal.
. Product Completeness
The winding temperature indicator consists of the following three parts:
1. A temperature indicator equipped with a heating element (model WTYK-04),as shown in Fig.1;
2. A power adaptor (model BL(DP)-(A), (B), (C) or (D)),as shown in Fig.1;
3.A remote indicator and controller installed in the contort center (Model XMT-288).
BL
BL Matching transformer
Fig. 1 External view
. Principle of Operation
After the transformer is loaded as shown in Fig.2, the current taken from the current
transformer (CT) is first adjusted by the power adaptor, and then flows through the heating element
Embedded in the elastic unit, where, the current is proportional to the load. The energy produced by
the heating element increases the displacement of the elastic unit; therefore, the displacement of the
elastic unit depends not only on the oil temperature of the transformer upper part but also the
loading current. The temperature indicated by the WTYK-04 is the summation of the oil
temperature of the transformer upper part and the winding temperature rise over oil, reflecting the
mean value of the hottest portion temperature of the measured transformer winding.
The power adaptor is a current converter used as the power supply for the WTYK-04 Fig.3
shows its electrical schematic diagram. First, the current Ip from the current transformer is
converted to an adjustable current Is, and then is applied to the heating element R embedded in the
WTYK-04. In this way, the mean value of the hottest portion temperature of the transformer
winding can be obtained
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