Impact of power system harmonics on insulation failure of distribution transformer and its remedial measures

Deokar, Sanjay A.; Waghmare, L. M.

doi:10.1109/icectech.2011.5941817

Cited by 18 publications

(9 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…6 The insulation failure may arise from insulation deterioration and subsequent dielectric breakdown. 6,7 Improving the performance of the liquid dielectric would increase the reliability of the transformer which subsequently would positively contribute to a reduction of power system losses.…”

Section: Introductionmentioning

confidence: 99%

Vegetable oil based liquid nanocomposite dielectric

2013

View full text Add to dashboard Cite

Physically smaller dielectric materials would improve the optimisation of space for power systems. Development of nanotechnology provides an effective way to improve the performances of insulating oils used in power system applications. In this research study, we focused on the development of nanomodified vegetable oils to be used in power transformers. Higher conduction currents were observed in virgin linseed oil than in virgin castor oil. However, for both virgin linseed and virgin castor oil, the DC conduction current increased approximately linearly with the applied DC voltage. In nanomodified linseed oil, the characteristic curve showed two distinct regions: a linear region (at lower applied voltage) and a saturation region (at slightly higher voltage). Conversely, in nanomodified castor oil, the characteristic curve showed three distinct regions: a linear region (at lower applied voltage), a saturation region (at intermediate applied voltage) and an exponential growth region (at higher applied voltage). The nanomodified linseed oil exhibited a better dielectric performance than the nanomodified castor oil. Overall, the addition of nanodielectrics to vegetable oils decreased the dielectric performance of the vegetable oils. The results of this study contribute to the understanding of the pre-breakdown phenomenon in liquid nanocomposite dielectrics.

show abstract

Section: Introductionmentioning

confidence: 99%

Vegetable oil based liquid nanocomposite dielectric

2013

View full text Add to dashboard Cite

show abstract

“…Derating distribution, industrial, or commercial transformers due to heating induced by harmonics distortion is a well-documented application [35][36][37][38][39]. As defined in Faiz, Ghazizadeh, and Oraee, the four methods applicable to derating transformers include IEEE recommendations, analytical methods, experimental approaches, and finite elements [14].…”

Section: Harmonic Distortion Evaluationmentioning

confidence: 99%

“…Historically, most system problems caused by harmonic distortion originate at a single source or customer, which prompts mitigation efforts to be directed exclusively at one location, bus, circuit, or subdistribution circuit. In fact, most research endeavors focus on derating transformers rated less than 2 MVA that serve mostly dedicated nonlinear loads [9,[35][36][37][38][39][40][41][42][43]. For substation transformers that serve a combination of residential, industrial, and commercial loads, accounting for harmonic is typically ignored due to the low levels of distortion and isolation of problems [1].…”

Section: Harmonic Distortion Evaluationmentioning

confidence: 99%

“…Therefore, it may be unlikely that the unit can deliver the same amount of peak demand without experiencing higher than expected internal temperatures and ergo increased loss of life. The best approach for preventing excessive aging of a unit is to derate the existing capacity limits [35][36][37][38][39][40][41][42][43]. Derating is established by reducing the peak energy demand of the unit to a level that maintains the hottest spot temperature (Θ H ) below acceptable levels according to IEEE Std.…”

Section: Existing Unit Derating-normal Operationsmentioning

confidence: 99%

See 1 more Smart Citation

Demand Side Management Effects on Substation Transformer Capacity Limits

2019

View full text Add to dashboard Cite

In high penetrations, demand side management (DMS) applications augment a substation power transformer’s load profile, which can ultimately affect the unit’s capacity limits. Energy storage (ES) applications reduce the evening peaking demand, while time-of-use rates incentivize end-users to charge electric vehicles overnight. The daily load profile is further augmented by high penetrations of photovoltaic (PV) systems, which reduce the midday demand. The resulting load profile exhibits a more flattened characteristic when compared to the historical cyclic profile. Although the initial impact of PV and ES applications may reduce a unit’s peak demand, long-term system planning and emergency conditions may require operation near or above the nameplate rating. Researchers have already determined that a flattened load profile excessively ages a unit’s dielectrics more rapidly. The focus of this research was to identify an approach for establishing new transformer capacity limits for units serving flattened load profiles with a high harmonic content. The analysis utilizes IEEE standards C57.91 and C57.110 to develop an aging model of a 50 MVA SPX Waukesha transformer. The results establish a guideline for determining transformer capacity limits for normal operation, long-term emergency operation, and short-term emergency operation when serving systems with high penetrations of DSM applications.

show abstract

“…Under non-linear load current where I 1 is equal to 1 pu, transformer losses increase leading to a rise in the temperature of different parts of the transformer and eventually the hot-spot temperature [22,23]. Therefore from insulation point of view, premature aging of the transformer insulation supplying non-linear load current with I 1 = 1pu is inevitable and a derating technique needs to be applied to ensure that the hot-spot temperature does not go beyond the permissible value.…”

Section: Thermal-insulation Requirements In Transformer Deratingmentioning

confidence: 99%

Derating of transformers under non‐linear load current and non‐sinusoidal voltage – an overview

Faiz

Ghazizadeh²,

Oraee³

2015

IET Electric Power Applications

View full text Add to dashboard Cite

The increasing application of non-linear loads in power system causes additional losses in transformers resulting in premature damage. Manufactures and users of transformers realise the importance of this phenomenon and it is vital to adopt a procedure to prevent it thereby enhancing the reliability of power system. To achieve this, the most common method is derating of transformers. This paper intends to review derating of transformers under nonsinusoidal operation, for which all available approaches are classified into four major methods including IEEE recommended, analytical, experimental and finite elements based method. For each method, the fundamental theory, significant factors related to derating, test techniques as well as advantages and disadvantages are discussed. The methods are then evaluated and compared with each other from different points of view. Moreover, the overall trend of a more precise derating method is suggested. This review clarifies the research areas which require attention in the future to advance the subject.

show abstract

Impact of power system harmonics on insulation failure of distribution transformer and its remedial measures

Cited by 18 publications

References 5 publications

Vegetable oil based liquid nanocomposite dielectric

Vegetable oil based liquid nanocomposite dielectric

Demand Side Management Effects on Substation Transformer Capacity Limits

Derating of transformers under non‐linear load current and non‐sinusoidal voltage – an overview

Contact Info

Product

Resources

About