Topics for further consideration.

Matlab Analysis And Simulation Of 

Ferroresonance 

Ferroresonance over voltage is a kind of inner over voltage that always occurs in neutral

ungrounded system and sometimes in neutral grounded system. The over voltage and over

current of ferroresonance do great harm to stable and safe running of power system. To keep the

transmission and distribution equipments out of damage, it is very important to research the

ferroresonance simulation model and detection method.Aim at 10 kV power substations,

considering the symmetry of the power distribution system, the Matlab simulation program is

used to research the ferroresonance simulation model, and the ferroresonance situation on this

substation 10kV PT is simulated. The simulation results indicate that the moment of the single

phase grounding fault disappearing is a key factor to excite ferroresonance.According to the

paper, the digital calculation and simulation will be regarded as the first way to research unlinear

ferroresonance. A saturable transformer model in the Simupower System box can be replaced

completely the potential transformer that will be needed in the simulation model. Any parameter

can be modified to simulate the actual system. Matlab is the most simulation software to

simulating unlinear system and the simulating result can be identical with the actual. And the

relatively positive analyses and estimation can be done.Additionally, another model had been built

to explore the way to restrain ferroresonance by installing capacitors against the ground.

Keywords:

unlinear ferroresonance,  potential transformer , Matlab simulating analys 

Study And Analysis Of PT Low Frequency

Non-line Oscillation And Suppression

Measure In Power Distribution Networks 

Along with the development of city distribution network, grounded capacitance of power system

larger as overhead lines lengthen and cables enlarge. Ferroresonance and low frequency non-liner

oscillation caused by potential transformer and grounded capacitance always occur in the system

neutral ungrounded. Appears high pressure insurance of PT frequent fuse even to burn down

phenomenon, it is enormous threat to the safety of electrical power system.The existing each kind

elimination way have the good suppression effect to ferroresonance, but for longer system line,

the parameter ratio of PT inductance and grounded capacitance has surpassed the ferroresonance

region, it enters low frequency non-liner oscillation region, it can produce large overvoltage and

overcurrent in PT.In this paper, a systemic simulations using Electro-magnetic Transient Program is

presented. It is simulation about all kind of ferroresonance and low frequencynon-liner oscillation

 

caused by single-phase earth fault disappeared in 6kV isolated neutral system. It presents some

correlation curves connected system parameters with overvoltage and overcurrent, and some

representative wave forms diagrams about overvoltage and overcurrent. It discussed suppression

effect of the existing each kind of elimination way to ferroresonace and low frequency non-liner

oscillation. A new elimination resolve overvoltage and overcurrent caused by ferroresonance and

low frequency non-liner oscillation, and it cans guarantee the safety and the reliability of power

system.

Keywords/Search

Tags: 

Potential Transformer , Electro-Magnetic Transient Program, 

Ferroresonance, Low frequency Non-liner Oscillation 

More topics.

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