With the rapid development of the construction of transmission lines and pipelines in China, the parallel approach, cross-crossing and criss-crossing of transmission lines and oil and gas transmission pipelines are inevitable. The electromagnetic influence of transmission lines on pipelines has become increasingly prominent. Therefore, to study the electromagnetic interference of transmission lines on oil and gas pipelines, this impact is controlled within the allowable range in engineering design and construction, which is of great significance for ensuring safe operation, controlling project investment, and promoting the construction of electric power and oil and gas transmission engineering. In this thesis, the Xining-Maerdang transmission line and the pipeline are parallel 45km. The electromagnetic effects of the steady-state conditions of the transmission line and single line-to-ground fault conditions on the oil and gas pipeline are analysed. The following studies have been carried out: Under steady-state conditions, a new method for measuring the electromagnetic influence of overhead transmission lines on pipelines was proposed. Field measurement experiments were conducted on the site and the distribution of pipeline potentials was obtained at the same time. The effects of factors such as soil resistivity, phase current, conductor-to-ground height, pipeline depth, phase spacing, pipeline leakage resistance, and the intersection angle between the pipeline and the transmission line on the interference voltage of the pipeline were studied. The results show that the pipeline potential changes with the distance between the pipeline and the transmission line, and the pipeline potential reaches the maximum at the intersection of the pipeline and the transmission line. And the pipeline potential increases with the increase of the soil resistivity and also increases with the phase current. The Faraday electromagnetic induction law was used to establish the circuit model in the case of a single line-to-ground fault in the transmission line. The mutual inductance and self-inductance of the fault line and pipeline were calculated based on the finite element method. The equations for the pipeline current were established, and the equations for the pipeline current were obtained. The pipeline voltage to ground was calculated by using the double-side elimination method. The influence of the short-circuit point position, the distance between the pipeline and the transmission line, the leakage resistance, the soil resistivity, the transmission line resistivity, and the fault current of the transmission line on the interference voltage of the oil and gas pipeline during the single line-to-ground fault of the transmission line was studied. The potential of the pipeline varies with the transmission line, and the position of the fault point has a great influence. The single line-to-ground fault analysis was performed on the Xining-Maerdang actual project. When a single line-to-ground fault occurred at the intersection of the transmission line and the pipeline, the pipeline potential reached its maximum value and was located near the fault point and exceeded the pipeline protection related limit value. The maximum potential point mitigation measures for pipelines during steady-state transmission line conditions and single line-to-ground fault were studied. The protective effects of laying bare copper strips, pipeline segment insulation, and changing the tower grounding resistance were analysed to provide technical support for actual project implementation. Considering multiple factors, Xining-Maerdang project should choose to place the bare copper strip at the maximum pipeline potential point for pipeline protection, and within the economical allowable range, the bare copper strip should be connected to the pipeline as many as possible, while increasing the length of bare copper strip and increasing the radius of the bare copper strip.
Con il rapido sviluppo della costruzione di linee di trasmissione e condotte in Cina, l'approccio parallelo, il “cross-crossing” e il “criss-crossing” delle linee di trasmissione con oleodotti e gasdotti sono inevitabili. L'influenza elettromagnetica delle linee di trasmissione sulle condotte è diventata sempre più importante. Pertanto, per studiare l'interferenza elettromagnetica delle linee di trasmissione su oleodotti e gasdotti, questo impatto è controllato all'interno della gamma consentita nella progettazione ingegneristica e nella costruzione, che è di grande importanza per garantire un funzionamento sicuro, controllando gli investimenti del progetto e promuovendo la costruzione di linee di trasmissione per l’energia elettrica, gas e petrolio. In questo lavoro, la linea di trasmissione Xining-Maerdang e il gasdotto sono paralleli a 45 km. Gli effetti elettromagnetici del funzionamento in regime stazionario della linea di trasmissione e i guasti monofase sul gasdotto e sul gasdotto sono stati analizzti. I seguenti studi sono stati svolti: In condizioni stazionarie, è stato proposto un nuovo metodo per misurare l'influenza elettromagnetica delle linee di trasmissione aeree sulle condotte. Esperimenti di misura sul campo sono stati condotti sul campo e la distribuzione dei potenziali delle tubazioni è stata ottenuta contemporaneamente. Sono stati studiati gli effetti di fattori quali resistività del suolo, corrente di fase, altezza conduttore-terra, profondità del condotto, distanza tra le fasi, resistenza di perdita del tubo e l'angolo di intersezione tra la tubazione e la linea di trasmissione sulla tensione di interferenza del tubo. I risultati mostrano che il potenziale del tubo aumenta con la distanza tra la tubazione e la linea di trasmissione e il potenziale di terra del tubo raggiunge il massimo all'intersezione della tubazione e della linea di trasmissione; il potenziale di terra del tubo aumenta con l'aumentare della resistività del suolo e aumenta anche con la corrente di fase. La legge di induzione elettromagnetica di Faraday è stata utilizzata per stabilire il modello del circuito nel caso di un guasto a terra monofase nella linea di trasmissione. L'induttanza reciproca e l'autoinduttanza della linea di faglia e della conduttura sono state calcolate in base al metodo degli elementi finiti. Sono state stabilite le equazioni per la corrente della tubazione e sono state ottenute le equazioni per la corrente della tubazione. La tensione della tubazione verso terra è stata calcolata utilizzando il metodo di eliminazione a doppio lato. L'influenza della posizione del punto di cortocircuito, la distanza tra la tubazione e la linea di trasmissione, la resistenza di dispersione, la resistività del suolo, la resistività della linea di trasmissione e la corrente di guasto della linea di trasmissione sulla tensione di interferenza del oleodotto e del gasdotto è stata studiata durante il guasto a terra monofase della linea di trasmissione. Il potenziale di terra della condotta varia con la linea di trasmissione e la posizione del punto di guasto ha una grande influenza. L'analisi dell'errore di messa a terra monofase è stata eseguita sul progetto attuale di Xining-Maerdang. Quando si è verificato un guasto monofase a terra all'intersezione della linea di trasmissione e della tubazione, il potenziale di terra del tubo ha raggiunto il suo valore massimo ed è stato collocato vicino al punto di guasto e ha superato il valore limite relativo alla protezione della tubazione. Sono state studiate le massime misure di mitigazione del punto potenziale per le condotte durante le condizioni di linea di trasmissione allo stato stazionario e guasti monofase a terra. Gli effetti protettivi della posa di strisce di rame nude, isolamento del segmento di tubo e modifica della resistenza di terra della torre sono stati analizzati per fornire supporto tecnico per l'effettiva realizzazione del progetto. Considerando molteplici fattori, il progetto Xining-Maerdang dovrebbe scegliere di posizionare la striscia di rame nuda al massimo potenziale di tubo per la protezione dei tubi, e all'interno della gamma economica ammissibile, collegare la striscia di rame nuda il più possibile, aumentando la lunghezza della striscia di rame nuda e aumentando il raggio della striscia di rame nuda.
Electromagnetic field interference of 750kV transmission line to buried pipelines
SUN, TIAN
2017/2018
Abstract
With the rapid development of the construction of transmission lines and pipelines in China, the parallel approach, cross-crossing and criss-crossing of transmission lines and oil and gas transmission pipelines are inevitable. The electromagnetic influence of transmission lines on pipelines has become increasingly prominent. Therefore, to study the electromagnetic interference of transmission lines on oil and gas pipelines, this impact is controlled within the allowable range in engineering design and construction, which is of great significance for ensuring safe operation, controlling project investment, and promoting the construction of electric power and oil and gas transmission engineering. In this thesis, the Xining-Maerdang transmission line and the pipeline are parallel 45km. The electromagnetic effects of the steady-state conditions of the transmission line and single line-to-ground fault conditions on the oil and gas pipeline are analysed. The following studies have been carried out: Under steady-state conditions, a new method for measuring the electromagnetic influence of overhead transmission lines on pipelines was proposed. Field measurement experiments were conducted on the site and the distribution of pipeline potentials was obtained at the same time. The effects of factors such as soil resistivity, phase current, conductor-to-ground height, pipeline depth, phase spacing, pipeline leakage resistance, and the intersection angle between the pipeline and the transmission line on the interference voltage of the pipeline were studied. The results show that the pipeline potential changes with the distance between the pipeline and the transmission line, and the pipeline potential reaches the maximum at the intersection of the pipeline and the transmission line. And the pipeline potential increases with the increase of the soil resistivity and also increases with the phase current. The Faraday electromagnetic induction law was used to establish the circuit model in the case of a single line-to-ground fault in the transmission line. The mutual inductance and self-inductance of the fault line and pipeline were calculated based on the finite element method. The equations for the pipeline current were established, and the equations for the pipeline current were obtained. The pipeline voltage to ground was calculated by using the double-side elimination method. The influence of the short-circuit point position, the distance between the pipeline and the transmission line, the leakage resistance, the soil resistivity, the transmission line resistivity, and the fault current of the transmission line on the interference voltage of the oil and gas pipeline during the single line-to-ground fault of the transmission line was studied. The potential of the pipeline varies with the transmission line, and the position of the fault point has a great influence. The single line-to-ground fault analysis was performed on the Xining-Maerdang actual project. When a single line-to-ground fault occurred at the intersection of the transmission line and the pipeline, the pipeline potential reached its maximum value and was located near the fault point and exceeded the pipeline protection related limit value. The maximum potential point mitigation measures for pipelines during steady-state transmission line conditions and single line-to-ground fault were studied. The protective effects of laying bare copper strips, pipeline segment insulation, and changing the tower grounding resistance were analysed to provide technical support for actual project implementation. Considering multiple factors, Xining-Maerdang project should choose to place the bare copper strip at the maximum pipeline potential point for pipeline protection, and within the economical allowable range, the bare copper strip should be connected to the pipeline as many as possible, while increasing the length of bare copper strip and increasing the radius of the bare copper strip.| File | Dimensione | Formato | |
|---|---|---|---|
|
2018_07_Sun Tian.pdf
non accessibile
Descrizione: Thesis
Dimensione
2.24 MB
Formato
Adobe PDF
|
2.24 MB | Adobe PDF | Visualizza/Apri |
I documenti in POLITesi sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
https://hdl.handle.net/10589/141874