The case of phase-to-phase fault in a 13.8 kV switchgear caused by heavy rain
In this case study we describe a 13.8 kV switchgear phase-to-phase fault due to by heavy rain evolving into a three-phase fault that was cleared by transformer numerical relays. The…...
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May 17, 2019 | By Edvard Csanyi
The basic protection schemes for 4 typical transformer types in power system
The degree of transformer protection provided depends to a great extent upon the size and functional importance of the unit. A further important factor is the economic aspect. The cost… Read more
May 13, 2019 | By Edvard Csanyi
Three good examples of the application of modern relays to transformer protection
This technical article provides three examples of the application of modern relays to transformer protection. As there are many modern protection relays nowadays that provide advanced software to simplify the… Read more
Apr 22, 2019 | By Edvard Csanyi
7 routine tests for a dry-type transformer you should perform during commissioning
This technical article briefly describes seven very important tests you should perform during commissioning of a dry-type transformer. Usually tests are performed in the factory where transformers are produced. The… Read more
Apr 03, 2019 | By Edvard Csanyi
Transformer no-load loss and excitation-current measurements
A transformer dissipates a constant no-load loss as long as it is energized at constant voltage, 24 h a day, for all conditions of loading. This power loss represents a… Read more
Mar 27, 2019 | By Edvard Csanyi
How not to overspecify high voltage CTs and VTs
The installations wherein CTs and VTs are mounted to measure the normal and abnormal values of current and voltage, have many variations in key system parameters, including voltage class, insulation… Read more
Feb 18, 2019 | By Edvard Csanyi
Connections and working principles of three-phase distribution transformers
A three-phase service can be supplied by one three-phase transformer unit or by interconnecting three single-phase transformer units. One three-phase unit is smaller than an equivalent size bank consisting of…...
Premium Membership Required
This technical article/guide requires a Premium Membership. You can choose an annually based Plus, Pro, or Enterprise membership plan. Subscribe and enjoy studying specialized technical articles, online video courses, electrical engineering guides, and papers. With EEP's premium membership, you get additional essence that enhances your knowledge and experience in low- medium- and high-voltage engineering fields.Check out each plan’s benefits and choose the membership plan that works best for you or your organization.
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Feb 08, 2019 | By Edvard Csanyi
Protection of a transformer directly connected to a transmission line without switchgear
A transformer-feeder include a transformer directly connected to a transmission line circuit without the intermediation of a HV switchgear. The saving in HV switchgear so achieved is unfortunately lowered by… Read more
Jan 28, 2019 | By Edvard Csanyi
How to determine power transformer impedance for calculation of short-circuit currents
In order to calculate short-circuit currents, it is obligatory to know conductor-specific equivalent data and impedances of electrical operational equipment, which are usually given by the respective manufacturer. The calculation…...
Premium Membership Required
This technical article/guide requires a Premium Membership. You can choose an annually based Plus, Pro, or Enterprise membership plan. Subscribe and enjoy studying specialized technical articles, online video courses, electrical engineering guides, and papers. With EEP's premium membership, you get additional essence that enhances your knowledge and experience in low- medium- and high-voltage engineering fields.Check out each plan’s benefits and choose the membership plan that works best for you or your organization.
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Jan 25, 2019 | By Edvard Csanyi
6 not-that-easy-to-understand terms related to a power transformer you should understand
There are many terms related to the power transformer operation that can be easily visualized which are especially important for students, like for example transformer construction or regular working principle…. Read more
Jan 21, 2019 | By Edvard Csanyi
Protection scheme for the substation with a single supply from the utility
The utility supply voltage depends on both availability and consumer requirements. The consumer transformer is connected delta on the high-voltage side and grounded wye on the low-voltage side. A fused-disconnect… Read more
Jan 07, 2019 | By Edvard Csanyi
Transformer pre-commissioning tests and after-receipt checks you MUST perform
Once oil filling is completed, various pre‐commissioning checks and tests are performed to ensure the healthiness of the transformer (or reactor) prior to its energization. Various electrical tests must be… Read more
Dec 26, 2018 | By Edvard Csanyi
The Essentials Of Current Transformers In Power Circuits (Theory and Practice)
If the voltage or current in a power circuit are too high to connect measuring instruments or relays directly, coupling is made through transformers. Such measuring transformers are required to… Read more
Dec 03, 2018 | By Edvard Csanyi
Coordinating study in protection of utility supply line, transformer and plant main bus/feeder
The installation of a dedicated substation to serve a plant actually involves an interface between the utility and the plant. Close coordination between utility and plant personnel is essential so… Read more
Nov 21, 2018 | By Edvard Csanyi
What is polarity and why it’s important for transformers and protection relays
Polarity is very important for the operation of transformers and protection equipment. A clear understanding of polarity is useful in understanding and analyzing transformer connections and operations as well as… Read more
Nov 19, 2018 | By Edvard Csanyi