Influence of Synchronous Condensers on Operation Characteristics of Double-Infeed LCC-HVDCs

Considering the advantages that dynamic reactive power (var) equipment (such as synchronous condensers (SCs), which can control var independently and improve voltage stability), SCs are widely used in AC/DC hybrid power grid to provide emergency var and voltage support. In order to evaluate the dynamic var reserve capacity of SCs and analyze the influence of SCs on the operation characteristics of power system, a model with double-infeed line-commutated converter-based high-voltage direct currents (LCC-HVDCs) and SCs is established. Through theoretical derivation and PSCAD/EMTDC simulation, the effects of SCs on the operation characteristics of double-infeed LCC-HVDCs networks are studied. Then, the non-smooth voltage waveform of electromagnetic transient simulation is approximately transformed into smooth waveform by data fitting method. Finally, the processed voltage waveform is searched step by step to explore the boundary of voltage safety region to determine the dynamic var reserve capacity of SCs. The numerical results show that SCs can enlarge the voltage security region of the direct current (DC) subsystem, thus effectively improving the steady-state and transient security level of the double-infeed LCC-HVDCs networks.

Download Full-text

Operation Characteristics of Zone 3 Distance Protection in Wind Power Systems with Fixed-Speed Induction Generators

International Journal of Emerging Electric Power Systems ◽

10.2202/1553-779x.2764 ◽

2011 ◽

Vol 12 (4) ◽

Cited By ~ 1

Author(s):

Shenghu Li

Keyword(s):

Power Systems ◽

Wind Power ◽

Reactive Power ◽

Flow Analysis ◽

Load Flow ◽

Synchronous Generators ◽

Induction Generators ◽

Load Flow Analysis ◽

Wind Power Systems ◽

Operation Characteristics

The induction generators (IGs) are basic to wind energy conversion. They produce the active power and consume the reactive power, with the voltage characteristics fragile compared with that of the synchronous generators and doubly-fed IGs. In the stressed system states, they may intensify var imbalance, yielding undesirable operation of zone 3 impedance relays.In this paper, the operation characteristics of the zone 3 relays in the wind power systems is studied. With the theoretical and load flow analysis, it is proved that the equivalent impedance of the IGs lies in the 2nd quadrature, possibly seen as the backward faults by the mho relays, i.e. the apparent impedance enters into the protection region from the left side. The undesirable operation may be caused by more wind power, larger load, less var compensation, and larger torque angle.

Download Full-text

Value- Based Real Time Reactive Power Pricing Model Considering Voltage Security and Reserve Requirement

2019 Modern Electric Power Systems (MEPS) ◽

10.1109/meps46793.2019.9395050 ◽

2019 ◽

Author(s):

Devika Jay ◽

K.S Swarup

Keyword(s):

Real Time ◽

Reactive Power ◽

Pricing Model ◽

Reserve Requirement ◽

Voltage Security

Download Full-text

Investigating the impacts of the SVCs and the SCs affecting to the transient stability in multi-machine power system

Science and Technology Development Journal ◽

10.32508/stdj.v19i2.643 ◽

2016 ◽

Vol 19 (2) ◽

pp. 16-24

Author(s):

Quang Huu Vinh Luu

Keyword(s):

Power System ◽

Transient Stability ◽

Reactive Power ◽

Voltage Regulation ◽

State Variables ◽

Static Var Compensators ◽

Transient Energy ◽

Voltage Frequency ◽

Power Outputs ◽

Synchronous Condensers

A new algorithm simulating the impacts of the VAR supporting devices such as the static var compensators (SVCs) and the synchronous condensers (SCs) under condition of symmetrical disturbances in multi-machine power system is mentioned. Some typical numerical examples are presented in this article. The comparisons of variation of the state parameters, such as the voltage, frequency, reactive power outputs and asynchronous torques…are simulated under condition of the action of the automatic voltage regulation systems of generators and of the VAR supporting devices. The transient energy margins are calculated and compared to assess the transient stability in multi-machine power system. Basing on this algorithm, the PC program uses the elements of the eigen-image matrix to bring the specific advantages for the simulation of the transient features of state variables.

Download Full-text