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Classical and Solid-state Tap-changers of HV/MV Regulating Transformers and their Regulators
Abstract
The paper presents the designs of classic and solid-state tap-changers for HV/MV regulating transformers. A simulation model was designed to assess the quality of voltage regulation with an on-load tap-changer. Disruption in this model is represented by a change in the demand and supply voltage of the transformer. Based on simulation studies, the paper presents the comparative characteristics of classic and solid-state tap-changers. The effect of replacing the classical tap-changer switch with a solid-state one on the regulator synthesis was also studied. Based on the analyses above new options of regulation with solid-state tap-changers have been formulated. The purpose of this paper is to determine the requirements for this new type of regulator for solid-state tap-changers and possible criteria for the operation of this control mechanism.
... The control algorithm for semiconductor tap-changers is completely different from that for electromechanical changers [15,16]. Neither frequency, nor number of the switching operations affects the system's service life, as is the case with electromechanical tap-changers. ...
... The module requires precise control to avoid damage to a single semiconductor element. Static tap changer switches have been extensively described in the literature, e.g. in [15][16][17][18][19][20][21][22][23][24]. In [25] the results are presented of simulations carried out in the Matlab Simulink environment with an electronic tap changer. ...
... Do komunikacji wykorzystano protokół Modbus. Proponowany układ kompensacji prądowej jest realizowany przez mikrokontroler.Półprzewodnikowe przełączniki zaczepówAlgorytm sterowania półprzewodnikowymi przełącznikami zaczepów jest zupełnie inny niż elektromechanicznymi[15,16]. Zarówno częstotliwość, jak i liczba operacji łączeniowych nie ma tu wpływu na trwałość układu, jak w elektromechanicznych przełącznikach zaczepów. ...
The purpose of the paper is to develop a new current compensation in the tap-changer controllers of HV/MV transformer. Problems in applying classical current compensation are presented. A mathematical model of current compensation has been created, taking into account the phase measurements offered by grid parameter meters. A new method of current compensation has been proposed for the controller of semiconductor tap-changers of HV/MV transformers.
... Saat ini, OLTC dengan pergerakan mekanikal yang menggunakan motor lebih banyak diterapkan pada transformator generator (transformator yang digunakan untuk menaikkan level tegangan keluaran generator pembangkit). Namun tap-changer jenis ini memiliki beberapa kekurangan seperti [7], [8] ...
Tap-changer merupakan alat bantu pada transformator daya yang berfungsi untuk mengubah perbandingan/rasio transformasi guna mendapatkan tegangan operasi sekunder yang sesuai dengan tegangan pelayanan. Seiring kemajuan teknologi, transformator pada saat ini telah menggunakan peralatan on-load tap-changer (OLTC) elektronik yang sepenuhnya tidak menggunakan kontak bergerak (moving contact) yang umum digunakan pada teknologi tap-changer mekanikal sebelumnya. Penggunaan OLTC elektronik dapat menghindari masalah busur api (arc) berlebihan yang muncul pada kontak diverter saat proses perubahan tap berlangsung. Kelebihan OLTC elektronik lainnya meliputi biaya pemeliharaan yang lebih rendah, kecepatan perubahan tap yang lebih tinggi, dapat melakukan tap jumping serta tidak adanya batasan dalam mengganti tap. Dalam tulisan ini akan dibahas perancangan OLTC elektronik untuk transformator berkapasitas 66 MVA yang digunakan untuk menaikkan level tegangan keluaran pembangkit sebesar 13,8 kV menjadi 150 kV. Rancangan OLTC elektronik ini dimaksudkan sebagai upaya untuk OLTC mekanikal yang saat ini digunakan, mempertimbangkan berbagai kelebihan yang dimiliki oleh OLTC elektronik. Secara umum, perancangan ini akan meliputi beberapa tahapan yaitu pengumpulan data OLTC mekanikal eksisting untuk mengetahui mekanisme kerjanya, menentukan spesifikasi saklar statis triac atau dua buah thyristor anti-paralel sebagai komponen utama OLTC elektronik, mensimulasikan rancangan OLTC elektronik serta menganalisis kinerja rancangan OLTC elektronik ditinjau dari aspek tegangan, arus, daya serta kecepatannya. Hasil analisis menunjukkan bahwa perbedaan level tegangan rancangan OLTC elektronik berkisar 1,22%-2,26%, yang dapat dikatakan sesuai dengan manualbook transformator yaitu sebesar 1,25%. Nilai arus dan tegangan rancangan OLTC elektronik juga telah sesuai dengan daya keluaran pembangkit. Rancangan OLTC elektronik juga terbukti mampu melakukan operasi tap-jumping dan memiliki waktu perubahan tap yang cepat yaitu rata-rata selama 1,109 detik untuk kenaikan tap yang berurutan serta 0,975 detik untuk tap-jumping.
... There are works on the use of semiconductor tap changers for voltage regulation in HV, MV and LV networks [3][4][5][6][7][8][9][10][11][12]. The differences between the electromechanical and semiconductor control algorithms are presented, among others, in [13,14]. There are applications of power semiconductors in high-voltage and high-power circuits, e.g., [15]. ...
The quality of electricity is a very important indicator. The durability and reliable operation of all connected devices depend on the quality of the network voltage. Rapid changes in loads, changes in network connections and the presence of uncontrolled energy sources require the development of new voltage regulation systems. This requires voltage regulation systems capable of responding quickly to sudden voltage changes. In substations with control transformers, it is possible thanks to the use of semiconductor tap changers. Moreover, voltage regulation and reactive power compensation systems should be built as one system. This is due to the close dependence of voltage and reactive power in the network node. Therefore, it was proposed to use artificial intelligence methods to build a new voltage regulation and reactive power compensation system using all measurement voltages of network nodes. In the first stage of the research, active and reactive powers, as well as the voltage of the reference node, were selected for 6420 periods of the mains voltage. The simulation results were compared for the classic voltage regulation system with semiconductor tap changers and the evolution algorithm based on voltage measurements from the entire MV network. A significant improvement in the quality of voltage regulation with the use of an evolutionary algorithm was demonstrated. Then, a second set of input data with increased values of reactive power was generated. The results of the evolutionary algorithm after the application of the classic, independent reactive power compensation system and two-criteria optimization were compared. It has been shown that only the two-criteria optimization algorithm keeps both |tgφ| within the acceptable range and the quality of voltage regulation is the best. The article compares different working algorithms for semiconductor tap changers.
... Power-electronic devices in power system are increasingly used. Therefore, the influence of the use of the electronics tap-changer with the controller implementing the classic algorithm [Korpikiewicz 2017;Korpikiewicz and Mysiak 2017a] was examined. A significant influence of the OLTC type on the quality of voltage regulation has been demonstrated. ...
... All TC can be divided into two main groups: mechanically operated [20][21][22][23][24][25][26] and based on pure electronic devices [27][28][29][30][31][32][33]. Mechanically operated TC, which are the most applicable today for control in feeder transformers, have a relatively slow time response extending to 5-10 s. ...
Widespread use of photovoltaic (PV) small and middle-power plants close or inside existing townships and villages may cause significant deviations of the grid voltage. Owing to the oscillation of solar irradiation and corresponding power flows these voltage instabilities can damage equipment and must be prevented. Designated for the voltage regulation tap-changers in distribution transformers located in a significant distance of such settlements have a sluggish response time. As a possible answer for their delay is the smoothing energy of flows in PV power installation by intermittent capacitor low-pass filtering (LPF) located near those PV facilities. The application of ultracapacitors (UC) for LPF is remarkable due to their sustainability and relatively low costs of energy storage. The parameters selection of such appliances is a well-designed procedure for linear circuits. However, DC–AC inverters in PV facilities are represented by a power (instead of a voltage) source. As a result, the total circuit including such LPF becomes a non-linear and its transient process and consequently, its efficiency is difficult to assess requiring each time of development the UC storage an application complex numerical procedure. Engineers are usual to work with linear circuits that are describing fine by a time constant is designated as a multiplication of a capacitance times load equivalent resistance. In the case of PV DC–AC inverters, such an approach can be applied as well but a value of a time constant should be corrected. Considering a significant cost of UC storage, the non-optimal selection of a correcting coefficient may cause considerable loses. Submitted in the presented article is an original approximation procedure giving an efficiently approachable technique to select correcting coefficient for describing non-linear dynamic process by its linear analog. This way the development low-pass UC filtering in electrical systems with PV plants becomes more efficient and simpler task.
... Badania zrealizowano stosując ogólnodostępne modele regulatora i transformatora. W artykule [7] zaprezentowano wpływ pracy przełącznika zaczepów na stabilność napięciową węzła sieci elektroenergetycznej. W artykule [8] przedstawiono transformator regulacyjny jako element wykonawczy układu regulacji dolnego napięcia. Przedstawiono klasyfikację przełączników zaczepów. ...
The article presents the voltage regulation system on the MV side of the 110 kV/15 kV station. The direction of voltage control depends on the place of installation of the tap changer and the method of switching on the control winding. The disturbing quantities in this system are changes in the voltage supplying the transformer, changes in the demand and generation balance in MV and LV networks. The construction and algorithm of the tap changer controller operation are presented on the example of the URT regulator. Requirements and assumptions for the simulation model created in Simulink were identified. The model was built to carry out simulation studies on the influence of the controller’s algorithm/construction on the quality of MV voltage regulation. In addition, this model will allow to assess the impact of unsteered sources connected to MV or LV networks on the quality of voltage regulation in these networks
... Badania zrealizowano stosując ogólnodostępne modele regulatora i transformatora. W artykule [7] zaprezentowano wpływ pracy przełącznika zaczepów na stabilność napięciową węzła sieci elektroenergetycznej. W artykule [8] przedstawiono transformator regulacyjny jako element wykonawczy układu regulacji dolnego napięcia. Przedstawiono klasyfikację przełączników zaczepów. ...
The article presents the voltage regulation system on the MV side of the 110 kV/15 kV
sta-tion. The direction of voltage control depends on the place of installation of the tap changer and
the method of switching on the control winding. The disturbing quantities in this system are changes
in the voltage supplying the transformer, changes in the demand and genera-tion balance in MV and
LV networks. The construction and algorithm of the tap changer con-troller operation are presented on
the example of the URT regulator. Requirements and as-sumptions for the simulation model created
in Simulink were identified. The model was built to carry out simulation studies on the influence of the
controller’s algorithm/construction on the quality of MV voltage regulation. In addition, this model will
allow to assess the impact of unsteered sources connected to MV or LV networks on the quality of
voltage regulation in these networks.
At present, the simulation model of the electromechanical tap changer controller is not generally available. It is necessary in order to carry out tests of the voltage regulation system in the Main Supply Point (MSP). It is a lower voltage regulation system. The article presents simulation models of the tap changer controller working in a HV/MV station. The construction of all subsystems of the model is presented. Various methods of implementation of current compensation were also considered. The subsystems of the model and the whole have been simulated.
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