ADAPTIVE MULTI-FUNCTION TRANSFORMER DIFFERENTIAL PROTECTIVE RELAY
Ahmed El-Sayed Hassan Saleh;
Abstract
The transformer differential protection is considered as the basic protection for power transformers. Due to the big importance of the transformer as a vital equipment in any power system, continuous development in the field of transformer protection is very important and an urgent necessity.
Transformer differential protection relays suffer mal-functions which sometimes lead to unwanted power interruption and as a result a large cost because of the loss of the power supply.
On the other hand, in some cases, the relay cannot detect the fault although it is an internal fault such as inter-turn faults that includes turn to turn and turn to ground faults which may cause damages for the short or long term in the transformer insulation and windings which is not required in the point of view of the transformer safety which may lead to a reduction in the life time of the transformer and also have a large cost of repairing the damaged transformers.
There are many reasons for transformer differential relay mal-function such as inrush current related to transformer energization, current transformer (CT) saturation due to high current flowing through the transformer protected zone in an external fault condition or in any other operating condition, a transformer overexcitation that may occur after clearing an external fault or sudden large load rejection from the power transformer load, and transformer winding faults with small fault current as incipient turn to turn or some turn to ground faults.
Many previous researches tried to solve the above mentioned problems that affect the performance of the transformer differential relay. This thesis restudied deeply many reasons of mal-function of the transformer differential protection relay and modified some existing protective algorithms in more accurate and simple manner by establishing a model of transformer inter-turn faults, adaptive differential relay and simulates different operating conditions in which the performance of the proposed differential protection relay model was tested.
Transformer differential protection relays suffer mal-functions which sometimes lead to unwanted power interruption and as a result a large cost because of the loss of the power supply.
On the other hand, in some cases, the relay cannot detect the fault although it is an internal fault such as inter-turn faults that includes turn to turn and turn to ground faults which may cause damages for the short or long term in the transformer insulation and windings which is not required in the point of view of the transformer safety which may lead to a reduction in the life time of the transformer and also have a large cost of repairing the damaged transformers.
There are many reasons for transformer differential relay mal-function such as inrush current related to transformer energization, current transformer (CT) saturation due to high current flowing through the transformer protected zone in an external fault condition or in any other operating condition, a transformer overexcitation that may occur after clearing an external fault or sudden large load rejection from the power transformer load, and transformer winding faults with small fault current as incipient turn to turn or some turn to ground faults.
Many previous researches tried to solve the above mentioned problems that affect the performance of the transformer differential relay. This thesis restudied deeply many reasons of mal-function of the transformer differential protection relay and modified some existing protective algorithms in more accurate and simple manner by establishing a model of transformer inter-turn faults, adaptive differential relay and simulates different operating conditions in which the performance of the proposed differential protection relay model was tested.
Other data
| Title | ADAPTIVE MULTI-FUNCTION TRANSFORMER DIFFERENTIAL PROTECTIVE RELAY | Other Titles | جهاز وقاية تفاضلية متأقلم ومتعدد الوظائف للمحولات | Authors | Ahmed El-Sayed Hassan Saleh | Issue Date | 2019 |
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