scholarly journals Influence of the Pulsed Voltage Connection on the Electromagnetic Distortion in Full-Size HVDC Cable PEA Measurements

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3087
Author(s):  
Guillermo Mier Escurra ◽  
Armando Rodrigo Mor ◽  
Peter Vaessen
Keyword(s):  
Power Systems ◽  
Direct Current ◽  
Electromagnetic Interference ◽  
Experimental Tests ◽  
Test Cell ◽  
Full Size ◽  
High Voltage Direct Current ◽  
Space Charges ◽  
Two Factors ◽  
Pulsed Voltage

Nowadays, with the widespread use of High Voltage Direct Current (HVDC) cables in power systems, the measurements of space charges in full-size cables are becoming more relevant. One of the most common methods used for space charge measurements is the Pulsed Electro-Acoustic (PEA) method. This paper analyzes two factors that influence the electromagnetic interference on the piezoelectric signal. These factors are the connection of the injected pulsed voltage at the PEA test cell and the grounding of the PEA test cell. The influence was analyzed by means of experimental tests to compare different configurations and the electromagnetic distortion created in each one of them. It was observed that the physical location of the pulsed voltage at the electrode has a very important impact on the magnitude of the electromagnetic distortion. Moreover, it is shown that the physical connection of the grounding and the existence of a parasitic capacitance at the PEA test cell are also an important source of distortion.

scholarly journals PEA Electromagnetic Distortion Reduction by Impedance Grounding and Pulsed Voltage Electrode Configurations

Sensors ◽  
2021 ◽  
Vol 21 (17) ◽  
pp. 5837
Author(s):  
Guillermo Mier Escurra ◽  
Armando Rodrigo Mor ◽  
Luis Carlos Castro ◽  
Peter Vaessen
Keyword(s):  
Experimental Testing ◽  
Test Cell ◽  
Acoustic Sensor ◽  
Direct Impact ◽  
High Voltage Direct Current ◽  
Space Charges ◽  
Two Factors ◽  
Distortion Reduction ◽  
Applied Voltage Pulse ◽  
Pulsed Voltage

Space charges are one of the main challenges facing the constantly increasing use of extruded high voltage direct current (HVDC) cables. The Pulsed Electro-Acoustic (PEA) method is one of the most common procedures for space charge measurements of insulation. One issue with the PEA method is distortion due to the crosstalk between the applied voltage pulse and the acoustic sensor. This work analyzed two factors involved in the reduction in this distortion: the influence of the exposed semiconductor distance between the injection electrodes and PEA test cell, and the influence of adding a reactance at the grounding circuit of the PEA test cell. The interaction of these two factors with the distortion was analyzed through a series of experimental testing. Moreover, the performance regarding distortion after applying a developed coaxial injection was compared with the standard non-coaxial injection configuration. It was observed that these two factors had a direct impact on distortion and can be utilized for the reduction in distortion arising from the crosstalk of the applied pulsed voltage. The results can be utilized for the consideration of practical aspects during the construction of a PEA test setup for the measurement of full-size HVDC cables.

Thermal breakdown in high voltage direct current cable insulations due to space charges

2018 ◽  
Vol 37 (5) ◽  
pp. 1689-1697 ◽  
Author(s):  
Christoph Jörgens ◽  
Markus Clemens
Keyword(s):  
Electric Field ◽  
Breakdown Voltage ◽  
High Voltage ◽  
Direct Current ◽  
Aging Effect ◽  
Radial Symmetry ◽  
Thermal Breakdown ◽  
Content Type ◽  
High Voltage Direct Current ◽  
Space Charges

Purpose In high voltage direct current (HVDC), power cables heat is generated inside the conductor and the insulation during operation. A higher amount of the generated heat in comparison to the dissipated one, results in a possible thermal breakdown. The accumulation of space charges inside the insulation results in an electric field that contributes to the geometric electric field, which comes from the applied voltage. The total electric field decreases in the vicinity of the conductor, while it increases near the sheath, causing a possible change of the breakdown voltage. Design/methodology/approach Here, the thermal breakdown is studied, also incorporating the presence of space charges. For a developed electro-thermal HVDC cable model, at different temperatures, the breakdown voltage is computed through numerical simulations. Findings The simulation results show a dependence of the breakdown voltage on the temperature at the location of the sheath. The results also show only limited influence of the space charges on the breakdown voltage. Research limitations/implications The study is restricted to one-dimensional problems, using radial symmetry of the cable, and does not include any aging or long-term effect of space charges. Such aging effect can locally increase the electric field, resulting in a reduced breakdown voltage. Originality/value A comparison of the breakdown voltage with and without space charges is novel. The chosen approach allows for the first time to assess the influence of space charges and field inversion on the thermal breakdown.

scholarly journals Comparative Study of AC and Positive and Negative DC Visual Corona for Sphere-Plane Gaps in Atmospheric Air

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2671 ◽  
Author(s):  
Jordi-Roger Riba ◽  
Andrea Morosini ◽  
Francesca Capelli
Keyword(s):  
Experimental Data ◽  
Field Strength ◽  
Electric Field ◽  
Power Systems ◽  
Electric Field Strength ◽  
High Voltage ◽  
Direct Current ◽  
Complex Nature ◽  
High Voltage Direct Current ◽  
Surface Electric Field

Due to the expansion of high-voltage direct current (HVDC) power systems, manufacturers of high-voltage (HV) hardware for alternating current (ac) applications are focusing their efforts towards the HVDC market. Because of the historical preponderance of ac power systems, such manufacturers have a strong background in ac corona but they need to acquire more knowledge about direct current (dc) corona. Due to the complex nature of corona, experimental data is required to describe its behavior. This work performs an experimental comparative analysis between the inception of ac corona and positive and negative dc corona. First, the sphere-plane air gap is analyzed from experimental data, and the corona inception voltages for different geometries are measured in a high-voltage laboratory. Next, the surface electric field strength is determined from finite element method simulations, since it provides valuable information about corona inception conditions. The experimental data obtained are fitted to an equation based on Peek’s law, which allows determining the equivalence between the visual corona surface electric field strength for ac and dc supply. Finally, additional experimental results performed on substation connectors are presented to further validate the previous results by means of commercial high-voltage hardware. The results presented in this paper could be especially valuable for high-voltage hardware manufacturers, since they allow determining the dc voltage and electric field values at which their ac products can withstand free of corona when operating in dc grids.

scholarly journals Latin Hypercube Sampling Method for Location Selection of Multi-Infeed HVDC System Terminal

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1646 ◽  
Author(s):  
Xiangqi Li ◽  
Yunfeng Li ◽  
Li Liu ◽  
Weiyu Wang ◽  
Yong Li ◽  
...  
Keyword(s):  
Power Systems ◽  
High Voltage ◽  
Direct Current ◽  
Latin Hypercube Sampling ◽  
Small Signal ◽  
Small Signal Stability ◽  
High Voltage Direct Current ◽  
Signal Stability ◽  
Load Demand ◽  
Oscillation Modes

Owing to the stochastic states of power systems with large-scale renewable generation, the impact of high-voltage direct current (HVDC) systems on the stability of the power system should be examined in a probabilistic manner. A probabilistic small signal stability assessment methodology to select the best locations for multi-infeed high-voltage direct current systems in alternating current (AC) grids is proposed in this paper. The Latin hypercube sampling-based Monte Carlo simulation approach is taken to generate the stochastic operation scenarios of power systems with the consideration of several stochastic factors, i.e., load demand and power generation. The damping ratio of the critical oscillation modes and the controllability of power injection to oscillation modes are analyzed by the probabilistic small signal stability. A probabilistic index is proposed to select the best locations of high-voltage direct current systems for improving the damping of the oscillation modes. The proposed methodology is applied to an IEEE 39 bus system considering the stochastic load demand and power generation. The results of probabilistic small signal stability assessment and a time-domain simulation show that the installation of a high-voltage direct current system on the selected locations can effectively improve the system damping.

scholarly journals Small signal stability analysis of a four-machine system with placement of multi-terminal high voltage direct current link

2020 ◽  
Vol 31 (1) ◽  
pp. 73-87
Author(s):  
Oluwafemi E. Oni ◽  
Andrew G. Swanson ◽  
Rudiren Pillay Carpanen
Keyword(s):  
Power Systems ◽  
High Voltage ◽  
Direct Current ◽  
Current System ◽  
Small Signal Stability ◽  
Critical Problem ◽  
Robust Controller ◽  
High Voltage Direct Current ◽  
Signal Stability ◽  
Small Signal Stability Analysis

Inter-area oscillation caused by weak interconnected lines or low generator inertia is a critical problem facing power systems. This study investigated the performance analysis of a multi-terminal high voltage direct current (MTDC) on the damping of inter-area oscillations of a modified two-area four-machine network. Two case studies were considered, utilising scenario 1: a double alternating current (AC) circuit in linking Bus_10 and Bus_11; and scenario 2: a three-terminal line commutated converter high voltage direct current system in linking Bus_6 and Bus_11 into Bus_9. It was found that scenario 2 utilising MTDC link with a robust controller provided quick support in minimising the network oscillations following a fault on the system. The MTDC converter controllers’ setup offered sufficient support for the inertia of the AC system, thus providing efficient damping of the inter-area oscillation of the system.

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