JPH06261444A - Method and equipment for suppressing exciting rush current of transformer - Google Patents
Method and equipment for suppressing exciting rush current of transformerInfo
- Publication number
- JPH06261444A JPH06261444A JP5044196A JP4419693A JPH06261444A JP H06261444 A JPH06261444 A JP H06261444A JP 5044196 A JP5044196 A JP 5044196A JP 4419693 A JP4419693 A JP 4419693A JP H06261444 A JPH06261444 A JP H06261444A
- Authority
- JP
- Japan
- Prior art keywords
- transformer
- voltage
- magnetic flux
- current
- residual magnetic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
- B23Q17/00—Arrangements for observing, indicating or measuring on machine tools
- B23Q17/09—Arrangements for observing, indicating or measuring on machine tools for indicating or measuring cutting pressure or for determining cutting-tool condition, e.g. cutting ability, load on tool
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明は変圧器を電力系統に投
入する際に発生する励磁突流を抑制するための変圧器励
磁突流抑制方法とその装置、特に位相投入方式に必要な
残留磁束の測定又はその設定方法とこれらの装置に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transformer exciting current suppression method and apparatus for suppressing the exciting magnetic surge generated when a transformer is applied to a power system, and in particular, the measurement of residual magnetic flux required for a phase injection method. Or, it relates to the setting method and these devices.
【０００２】[0002]
【従来の技術】変圧器を直接電源に投入すると励磁突流
と呼ばれる過渡的な電流が一次側に流れることはよく知
られている。その最大値は変圧器の容量にもよるが定格
電流の数倍ないし十数倍にもなる。励磁突流の発生は変
圧器内部の異常を検出するための差電流継電器の誤動作
の原因になること、系統に瞬間的な電圧降下が生ずるな
どの問題が生ずる。そのため、励磁突流抑制のための種
々な方法が検討されている。励磁突流発生は変圧器鉄心
の非線型飽和特性とそのヒステリシス現象によって生ず
るもので、電源遮断後に変圧器鉄心中に残る磁束、いわ
ゆる残留磁束によって励磁突流の値がなおさら増大する
という現象が特に重要である。励磁突流はその変圧器に
電圧を印加する時の位相によりその値は変わりまた電圧
遮断時の位相によって残留磁束の値が変わるので励磁突
流の大きさは不確定であるが、その値が最大となる条件
とその値について検討されたりその値に基づいて対策が
立てられたりする。この条件での励磁突流発生現象につ
いて図６、図７及び図８を基に説明する。2. Description of the Related Art It is well known that when a transformer is directly applied to a power source, a transient current called an exciting rush current flows to the primary side. The maximum value depends on the capacity of the transformer, but can be several to ten times the rated current. The generation of the exciting rush current causes problems such as a malfunction of the differential current relay for detecting an abnormality inside the transformer and a momentary voltage drop in the system. Therefore, various methods have been studied for suppressing the magnetizing rush current. Excitation rush current occurs due to the non-linear saturation characteristics of the transformer core and its hysteresis phenomenon, and the phenomenon that the value of the excitation rush current is further increased by the magnetic flux remaining in the transformer core after the power is cut off, so-called residual magnetic flux, is particularly important. is there. The magnitude of the magnetizing excursion is uncertain because the value changes depending on the phase when a voltage is applied to the transformer and the value of the residual magnetic flux changes depending on the phase when the voltage is cut off. Conditions and their values will be examined and measures will be taken based on those values. The phenomenon of magnetizing surge flow under these conditions will be described with reference to FIGS. 6, 7 and 8.
【０００３】図６は変圧器を含む結線図、図７はこの変
圧器に電源投入時の電圧等の時間的変化を示す波形図、
図８は変圧器の鉄心のヒステリシスループの図である。
図６において、単相の電源６５の電圧Ｖg が丁度零にな
る時点に開閉器６２が閉じて変圧器６１の一次側に印加
されたとする。この電源６５の電圧Ｖg に相当する逆起
電圧が発生するためには鉄心中の磁束密度Ｂは図７のＢ
0 の波形とならねばならない。すなわち、この電圧に対
する定常状態での鉄心中の定格磁密度をＢm とすると図
７の磁束密度の最大値Ｂs はこのＢm の２倍と残留磁束
密度Ｂr との和となり、次式で表される。FIG. 6 is a wiring diagram including a transformer, FIG. 7 is a waveform diagram showing temporal changes in voltage and the like when the transformer is powered on,
FIG. 8 is a diagram of a hysteresis loop of an iron core of a transformer.
In FIG. 6, it is assumed that the switch 62 is closed and applied to the primary side of the transformer 61 at the time when the voltage Vg of the single-phase power source 65 becomes just zero. In order to generate the counter electromotive voltage corresponding to the voltage Vg of the power source 65, the magnetic flux density B in the iron core is B in FIG.
The waveform should be 0 . That is, assuming that the rated magnetic density in the iron core in the steady state for this voltage is B m , the maximum value B s of the magnetic flux density in FIG. 7 is the sum of twice this B m and the residual magnetic flux density B r. expressed.
【０００４】 Ｂs ＝２Ｂm ＋Ｂr ‥‥‥‥‥‥‥‥‥‥‥（１） 図８は変圧器鉄心のヒステリシスループの模式図であ
る。この図において、定格磁束密度Ｂm はヒステリシス
ループの右先端部のＭ点の磁束密度であり、このとき磁
界強度Ｈも最大となる。飽和磁束密度Ｂh は珪素鋼板で
は２Ｔであるが、定格磁束密度Ｂm は種々の点が考慮さ
れて適切な値が設定される。その値は当然飽和磁束密度
Ｂh よりも小さい。Bs = 2B m + B r ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ (1) Fig. 8 is a schematic diagram of a hysteresis loop of a transformer core. In this figure, the rated magnetic flux density B m is the magnetic flux density at the point M at the right end of the hysteresis loop, and at this time the magnetic field strength H is also maximum. The saturation magnetic flux density B h is 2T for a silicon steel sheet, but the rated magnetic flux density B m is set to an appropriate value in consideration of various points. The value is naturally smaller than the saturation magnetic flux density B h .
【０００５】ヒステリシスループの上の曲線である下降
線をＭ点から下降して縦軸に到った点の磁束密度Ｂが最
大の残留磁束密度Ｂr である。実際の変圧器鉄心では交
流電圧が印加されているのでヒステリシスループの中に
は鉄心中の渦電流成分も含まれてヒステリシスループの
横幅が広くなっているために、図８を交流ヒステリシス
ループだとすると残留磁束密度Ｂr はこの位置よりも少
し下になるが、ここでは交流ヒステリシスループと直流
ヒステリシスループとは同じとして扱う。The maximum residual magnetic flux density B r is the magnetic flux density B at the point on the vertical axis after descending from the point M on the descending line which is the upper curve of the hysteresis loop. Since an AC voltage is applied to an actual transformer iron core, the hysteresis loop also includes an eddy current component in the iron core, and the width of the hysteresis loop is wide. Although the magnetic flux density B r is slightly lower than this position, the AC hysteresis loop and the DC hysteresis loop are treated as the same here.
【０００６】変圧器鉄心に使用される珪素鋼板の飽和磁
束密度Ｂh に対して定格磁束密度Ｂ m は８０％以上に設
計されるのが一般であり、また残留磁束密度Ｂr の最大
値は定格磁束密度Ｂm の７０％程度なので（１）式の磁
束密度の最大値Ｂs の最大値は飽和磁束密度Ｂh の約２
２０％になる。 図７で磁束密度Ｂが飽和磁束密度Ｂ h
より小さい時は鉄心の比透磁率は非常に大きいことから
一次巻線のインダクタンスは非常に大きいので励磁電流
Ｉe は小さく図７では無視して零として表示している。
磁束密度Ｂが飽和磁束密度Ｂh より大きくなると鉄心中
の磁束密度は飽和してしまい一次巻線のインダクタンス
は空心のインダクタンスとなり、この値は定格電圧と定
格電流の比を定格インピーダンスとしてその数分の１な
ので、この時の電流は定格電流の数倍となる。この電流
が励磁突流であり図７のＩp である。数１０ＭＶＡ程度
の変圧器の励磁電流の大きさは定格電流の１％以下故こ
の励磁電流Ｉe は励磁突流Ｉp の大きさに比べて略３桁
小さい。Saturated magnetism of silicon steel sheet used for transformer core
Bunch density BhFor the rated magnetic flux density B mSet above 80%
Generally, the residual magnetic flux density BrMaximum of
The value is the rated magnetic flux density BmSince it is about 70% of the
The maximum value of the flux density Bs is the saturation magnetic flux density BhAbout 2
It will be 20%. In FIG. 7, the magnetic flux density B is the saturated magnetic flux density B h
When it is smaller, the relative permeability of the iron core is very large.
Since the inductance of the primary winding is very large, the exciting current
Ie is small and ignored in FIG. 7 and is displayed as zero.
Magnetic flux density B is saturation magnetic flux density BhWhen it gets bigger, the iron core
The magnetic flux density of is saturated and the inductance of the primary winding
Is the inductance of the air core, and this value is constant with the rated voltage.
The rated current ratio is the rated impedance,
Therefore, the current at this time is several times the rated current. This current
Is the exciting rush current and is Ip in FIG. About 10 MVA
The magnitude of the exciting current of the transformer is less than 1% of the rated current.
The exciting current Ie is about 3 digits compared to the magnitude of the exciting surge Ip.
small.
【０００７】図７での点線で示した磁束密度Ｂ0 、励磁
突流Ｉp0は巻線などの抵抗を無視した時の波形である
が、実際にはこの抵抗があるために励磁突流Ｉp は抵抗
分だけ小さくなりこれに伴って磁束密度Ｂの波形も下に
下がり直流成分が減衰し次のサイクルでは飽和磁束密度
Ｂh を越える部分が小さくなり従ってこのサイクルでの
励磁突流Ｉp も小さくなる。このように励磁突流は回路
の抵抗成分によって時間と共に減衰し、いずれ定常状態
に達する。The magnetic flux density B 0 and the exciting rush current Ip 0 shown by the dotted line in FIG. 7 are waveforms when the resistance of the winding and the like is ignored. However, since there is this resistance, the exciting rush current Ip is the resistance. It becomes smaller by that amount, and the waveform of the magnetic flux density B goes down accordingly, and the direct current component is attenuated. In the next cycle, the portion exceeding the saturated magnetic flux density B h becomes small, and therefore the exciting rush current Ip in this cycle also becomes small. In this way, the exciting rush current decays with time due to the resistance component of the circuit and eventually reaches a steady state.
【０００８】励磁突流最大値としての励磁突流の値は変
圧器の容量によって変わり、一般に変圧器容量の大きい
程励磁突流の定格電流に対する比率は低下する。１０万
ＫＶＡ前後の大容量器が５ないし６倍、千ＫＶＡ前後の
小容量の変圧器では１０倍前後である。The value of the exciting surge current as the maximum value of the exciting surge current changes depending on the capacity of the transformer, and generally, the larger the transformer capacity, the lower the ratio of the exciting surge current to the rated current. It is about 5 to 6 times for large capacity transformers around 100,000 KVA, and about 10 times for small capacity transformers around 1,000 KVA.
【０００９】[0009]
【発明が解決しようとする課題】励磁突流を抑制する方
法としては種々あるが、原理的に効果的な方法として位
相投入方式が知られている。その方法も幾つかのものが
提案されているがそれぞれに技術的課題があって実用化
されるには至っていないのが実際である。この発明は、
このような問題を解決し、実用可能な変圧器励磁突流抑
制方法とその装置を提供することにある。Although there are various methods for suppressing the magnetizing surge current, the phase injection method is known as an effective method in principle. Several methods have been proposed, but each method has technical problems and has not been put into practical use. This invention
It is an object of the present invention to solve the above problems and provide a practical method and apparatus for suppressing a transformer excitation surge current.
【００１０】[0010]
【課題を解決するための手段】上記課題を解決するため
に、この発明によれば、無電圧状態の変圧器にパルス状
の電圧を印加し、このときの印加電圧と流入電流を測定
し、これらを演算器に入力して変圧器の残留磁束を演算
するとともに、この残留磁束演算値に基づいて励磁突流
を抑制する投入位相を演算し、この演算結果に基づいて
変圧器を電源投入するものとし、また、無電圧状態の変
圧器に単極性のパルス電圧を印加することによって、変
圧器の残留磁束を所定の値に設定し、設定された残留磁
束に応じた励磁突流を抑制する投入位相に基づいて変圧
器を電源投入するものとし、また、変圧器の鉄心に測定
用コイルが巻回されその端子が外部に引き出されてな
り、この端子にパルス発生器によるパルス電圧を印加す
るものとし、また、強磁性棒に測定用コイルが巻回され
た磁気センサを変圧器の鉄心に磁気的に近接して設け、
この測定用コイルにパルス電圧を印加して印加電圧と流
入電流を測定し、これらを演算器に入力して間接的に変
圧器の残留磁束を演算するとともに、残留磁束演算値に
基づいて励磁突流を抑制する投入移相を演算し、この演
算結果に基づいて変圧器を電源投入するものとする。In order to solve the above problems, according to the present invention, a pulsed voltage is applied to a transformer in a non-voltage state, and the applied voltage and inflow current at this time are measured, These are input to a calculator to calculate the residual magnetic flux of the transformer, the closing phase that suppresses the magnetizing rush current is calculated based on this residual magnetic flux calculation value, and the transformer is turned on based on this calculation result. In addition, by applying a unipolar pulse voltage to the transformer in the no-voltage state, the residual magnetic flux of the transformer is set to a specified value, and the closing phase that suppresses the exciting magnetic rush current according to the set residual magnetic flux. The transformer shall be powered on based on the above, and the measuring coil shall be wound around the transformer core and its terminals shall be pulled out to the outside, and the pulse voltage from the pulse generator shall be applied to this terminal. ,Also, Provided a magnetic sensor that is measuring coil wound around the magnetic pole magnetically close to the core of the transformer,
A pulse voltage is applied to this measuring coil to measure the applied voltage and the inflow current, and these are input to a calculator to indirectly calculate the residual magnetic flux of the transformer, and the exciting magnetic flux current is calculated based on the residual magnetic flux calculation value. Is calculated, and the transformer is powered on based on the calculation result.
【００１１】[0011]
【作用】この発明の構成において、無電圧状態の変圧器
にパルス状の電圧を印加し、このときの印加電圧と流入
電流を測定すると、残留磁束の大きさに対応した電圧と
電流の関係があるのでこの関係を基に残留磁束の大きさ
を求めることができる。したがって、電圧と電流の測定
値を演算器に入力して変圧器の残留磁束を演算すること
ができる。残留磁束が求められれば励磁突流を抑制する
投入位相を求めることができるので、前述の残留磁束と
ともに投入位相を演算で求めこの演算結果に基づいて変
圧器を電源投入することによってその際の励磁突流を抑
制することができる。In the structure of the present invention, when a pulsed voltage is applied to the transformer in the no-voltage state and the applied voltage and the inflow current at this time are measured, the relationship between the voltage and the current corresponding to the magnitude of the residual magnetic flux is found. Therefore, the magnitude of the residual magnetic flux can be obtained based on this relationship. Therefore, the residual magnetic flux of the transformer can be calculated by inputting the measured values of the voltage and current to the calculator. If the residual magnetic flux is obtained, it is possible to obtain the closing phase that suppresses the exciting surge. Therefore, calculate the closing phase together with the above-mentioned residual flux, and based on this calculation result, turn on the power of the transformer to generate the exciting surge. Can be suppressed.
【００１２】また、無電圧状態の変圧器に単極性のパル
ス電圧を印加すると残留磁束はパルス電圧の極性に応じ
てその値が変化するので、これを用いて残留磁束を変化
させ所定の値に設定し、設定された残留磁束に応じた投
入位相に基づいて変圧器を電源投入することによっても
励磁突流を抑制することができる。また、変圧器の鉄心
に測定用コイルを巻回しその端子を外部に引き出す構成
を採用し、この端子にパルス発生器によるパルス電圧を
印加して前述のように投入位相を求めて励磁突流を抑制
した電源投入を行うことができる。When a unipolar pulse voltage is applied to a voltageless transformer, the residual magnetic flux changes its value depending on the polarity of the pulse voltage. Therefore, the residual magnetic flux is changed to a predetermined value by using this. The magnetizing surge can also be suppressed by setting and turning on the power of the transformer based on the making phase corresponding to the set residual magnetic flux. In addition, we adopted a configuration in which the measuring coil is wound around the iron core of the transformer and its terminal is pulled out to the outside, and the pulse voltage from the pulse generator is applied to this terminal to find the closing phase and suppress the exciting rush current as described above. The power can be turned on.
【００１３】また、強磁性棒に測定用コイルを巻回した
磁気センサを変圧器の鉄心に磁気的に近接して設けてお
き、測定用コイルにパルス電圧を印加して印加電圧と流
入電流を測定してこれらを演算器に入力して強磁性棒の
残留磁束を求めると、この残留磁束は変圧器鉄心の残留
磁束に対応するので間接的に変圧器鉄心の残留磁束を求
めたことになり、その値に基づいて投入位相を演算し、
この演算結果に基づいて変圧器を電源投入するもことに
よって励磁突流を抑制することができる。Further, a magnetic sensor in which a measuring coil is wound around a ferromagnetic rod is provided magnetically close to the iron core of the transformer, and a pulse voltage is applied to the measuring coil to detect the applied voltage and the inflow current. When the measured values are input to the calculator and the residual magnetic flux of the ferromagnetic rod is calculated, this residual magnetic flux corresponds to the residual magnetic flux of the transformer core, so it means that the residual magnetic flux of the transformer core is indirectly calculated. , Calculate the closing phase based on that value,
The magnetizing surge can be suppressed by turning on the power of the transformer based on the calculation result.
【００１４】[0014]
【実施例】以下この発明を実施例に基づいて説明する。
図１はこの発明の実施例を示す変圧器励磁突流抑制装置
を示す回路図である。この図において、変圧器１は巻線
１１、１３及び鉄心１２からなっていて、巻線１１の端
子にパルス発生器４が接続され巻線１３の端子は開放さ
れている。変圧器１は過去に励磁された実績があるのが
普通である。したがって、前述のように鉄心１２には残
留磁束が残っているので、次に電力系統に投入するとき
に励磁突流が発生する要因を抱えている。EXAMPLES The present invention will be described below based on examples.
FIG. 1 is a circuit diagram showing a transformer excitation surge suppressor showing an embodiment of the present invention. In this figure, a transformer 1 comprises windings 11 and 13 and an iron core 12, a terminal of the winding 11 is connected to a pulse generator 4, and a terminal of the winding 13 is open. The transformer 1 usually has a history of being excited in the past. Therefore, since the residual magnetic flux remains in the iron core 12 as described above, there is a factor that an exciting rush current occurs when the iron core 12 is next applied to the power system.
【００１５】パルス発生器４の端子電圧、言い換えれば
巻線１１の印加電圧はコンデンサ分圧器である電圧測定
器２によって測定され、流入電流が変流器である電流測
定器３によって測定される。パルス発生器４は直流電源
４１、抵抗４２、スイッチ４３、コンデンサ４４，４５
からなっていて、直流電源４１によって抵抗４２を介し
てコンデンサ４４が所定の電圧まで充電された後スイッ
チ４３がオンになってコンデンサ４４の電圧がコンデン
サ４５と分圧される形で変圧器１にパルス電圧が印加さ
れる。この図ではコンデンサ４４が充電されるときの直
流電源４１に戻る回路がないが、実際のパルス発生器４
は多数のコンデンサ４４が多数の抵抗４２を介して並列
接続された状態で直流電源４１によって充電され、これ
ら梯子状の回路に挿入されている多数のスイッチを一度
にオンにすることによって高電圧が発生するものであ
る。このようパルス発生器４の構成は変圧器の絶縁試験
に使用される衝撃電圧発生器などに一般に採用されてい
るものであり、超々高圧の発生も容易である。その代わ
りパルス幅がミリ秒程度又はそれ以下の急峻な波形が得
られるのが普通である。実際のパルス発生器４では波形
調整のための抵抗やインダクタが付加される場合があ
る。The terminal voltage of the pulse generator 4, in other words the voltage applied to the winding 11, is measured by the voltage measuring device 2 which is a capacitor voltage divider, and the inflow current is measured by the current measuring device 3 which is a current transformer. The pulse generator 4 includes a DC power supply 41, a resistor 42, a switch 43, capacitors 44 and 45.
After the capacitor 44 is charged to a predetermined voltage by the DC power supply 41 through the resistor 42, the switch 43 is turned on and the voltage of the capacitor 44 is divided by the capacitor 45 into the transformer 1. A pulse voltage is applied. Although there is no circuit for returning to the DC power supply 41 when the capacitor 44 is charged in this figure, the actual pulse generator 4
Is charged by the DC power supply 41 with a large number of capacitors 44 connected in parallel via a large number of resistors 42, and by turning on a large number of switches inserted in these ladder-like circuits at once, a high voltage is generated. It occurs. Such a configuration of the pulse generator 4 is generally adopted in an impulse voltage generator used for a transformer insulation test, and it is easy to generate ultra-high voltage. Instead, a steep waveform having a pulse width of about millisecond or less is usually obtained. In the actual pulse generator 4, a resistor or an inductor for waveform adjustment may be added.
【００１６】このパルス発生器４によってパルス電圧を
印加して変圧器１を励磁し、そのときの印加電圧ｖと流
入電流ｉの関係から鉄心の残留磁束を求め、その値から
最適の投入位相を求めようとするものである。図２は図
１においてパルス電圧が印加されたときの鉄心１２のヒ
ステリシスループの変化を模式的に示すヒステリシスル
ープの図であり、実線で示すヒステリシスループは図８
のそれと同じである。なお、この図の磁束密度Ｂは前述
の電圧ｖを時間積分して巻線１１の巻数と鉄心１２の断
面積で割って得られ、磁界強度Ｈは電流ｉに巻数を掛け
て得られたアンペアターンを鉄心１２の磁路長で割った
値である。これらの計算に必要な変圧器１の諸元は設計
値を使用して実用的に充分である。なお、ヒステリシス
ループは実測によって得ることもできる。A pulse voltage is applied by the pulse generator 4 to excite the transformer 1, the residual magnetic flux of the iron core is obtained from the relationship between the applied voltage v and the inflow current i at that time, and the optimum closing phase is determined from that value. It is what you seek. FIG. 2 is a diagram of a hysteresis loop schematically showing changes in the hysteresis loop of the iron core 12 when the pulse voltage is applied in FIG. 1, and the hysteresis loop shown by the solid line is shown in FIG.
It is the same as that of. The magnetic flux density B in this figure is obtained by time-integrating the aforementioned voltage v and dividing it by the number of turns of the winding 11 and the cross-sectional area of the iron core 12, and the magnetic field strength H is obtained by multiplying the current i by the number of turns. It is a value obtained by dividing the turn by the magnetic path length of the iron core 12. The specifications of the transformer 1 required for these calculations are practically sufficient using the design values. The hysteresis loop can also be obtained by actual measurement.
【００１７】今仮に鉄心１２の残留磁束がヒステリシス
ループ上の図示のＰ点にあり、これに正極性のパルス電
圧を印加したとする。正極性の電圧とはこの図で磁束密
度Ｂが増大する極性のことである。このとき、磁界強度
Ｈと磁束密度Ｂとは図のＰ点から始まる一点鎖線の曲線
Ｐ 1 の軌跡を描いて変化する。なお、鎖線で示すＰ点か
ら始まる曲線Ｐ0 は渦電流が無視できる程度に遅い変化
の正の励磁電流が流れた場合のＢ─Ｈの変化を示す軌跡
であり、参考に示したものである。曲線Ｐ1 はパルス電
圧の時間的変化は商用周波レベルの変化に比べて充分速
い変化の波形であることを前提にしている。Now, temporarily, the residual magnetic flux of the iron core 12 has hysteresis.
It is at the point P on the loop and has a positive pulse voltage.
It is assumed that pressure is applied. The positive voltage is the magnetic flux density in this figure.
The polarity is such that the degree B increases. At this time, the magnetic field strength
H and magnetic flux density B are the dashed line curves starting from point P in the figure
P 1It changes by drawing the trajectory of. In addition, is it P point shown by the chain line?
Curve P starting from0Is a slowly changing eddy current that can be ignored
Locus showing the change of B-H when the positive excitation current of B flows
And is shown for reference. Curve P1Is pulsed
The change in pressure with time is sufficiently faster than the change in commercial frequency level.
It is assumed that the waveform has a large change.
【００１８】Ｐ点とは符号が反対側のＱ点にあるとき、
すなわ残留磁束密度が−Ｂr のときに同じように正極性
のパルス電圧を印加したとすると、Ｈ−Ｂ特性はＱ点か
ら始まる一点鎖線で示す曲線Ｑ1 を描く。実際には電圧
のオーバーシュートなどがあって図示のような単純な曲
線にはならないことが多いがここでは単純化してある。
曲線Ｐ1 の最終点はＰ点になって磁束密度の最初と最後
の変化は零である。一方、曲線Ｑ1 は最終点がＱ点より
も上の位置になって磁束密度の変化分ΔＢだけ残留磁束
が変化したことになる。なお、Ｐ点にあるときに負極性
のパルス電圧を印加した場合には前述のＱ点に正極性の
パルス電圧を印加したときと符号が反転するだけで現象
は同じである。When the sign is at the point Q opposite to the point P,
When Sunawa residual magnetic flux density and applied similar positive polarity pulse voltage when the -B r, H-B characteristic draws a curve Q 1 shown by the one-dot chain line starting from the point Q. In reality, there are voltage overshoots and the like, which often does not result in a simple curve as shown, but it is simplified here.
The final point of the curve P 1 is the point P, and the first and last changes in the magnetic flux density are zero. On the other hand, in the curve Q 1, the final point is located above the point Q, and the residual magnetic flux changes by the change ΔB in the magnetic flux density. When the negative pulse voltage is applied at the point P, the phenomenon is the same as that when the positive pulse voltage is applied to the point Q, only the sign is reversed.
【００１９】曲線Ｐ1 とＱ1 とを比較したときにそれぞ
れの相違点を列挙すると次の通りである。 最初と最後の磁束密度の差であるΔＢの値が違う。Ｑ
1 の方が大きい。 磁界強度の最大変化量ΔＨの値が違う。Ｐ1 の方が大
きい。 曲線の最初の部分の傾斜が違う。Ｑ1 の方が大きい。The differences between the curves P 1 and Q 1 are listed below. The value of ΔB, which is the difference between the first and last magnetic flux densities, is different. Q
1 is larger. The maximum change amount ΔH of the magnetic field strength is different. P 1 is larger. The slope of the first part of the curve is different. Q 1 is larger.
【００２０】したがって、このような相違のうちのどれ
か１つを検出することによって残留磁束がＰ点にあるか
Ｑ点にあるかを求めることができる。勿論、２つ以上を
併用して精度を向上させることもできる。前述のの曲
線の最初の部分の傾斜の違いは図では必ずしも明確では
ないが、Ｐ点では鎖線で示す曲線Ｐ0 、Ｑ点では実線の
ヒステリシスループの曲線の縦軸であるＢ軸の 近くで
の傾斜を比べると、Ｑ点の方が大きいのは明らかであ
る。この傾斜はそのヒステリシスループの位置での偏分
透磁率と呼ばれものである。曲線Ｐ1 やＱ1 に含まれる
渦電流成分もこの偏分透磁率の影響を受けて結果的に正
極性の電圧が印加された場合のヒステリシスループの最
初の分では前述ののような結果になる。ただ、電圧の
時間変化が速い場合には渦電流の影響が大きくなって、
双方とも最初の部分の傾斜が非常に小さくなって判別す
ることが困難になるという傾向がある。Therefore, it is possible to determine whether the residual magnetic flux is at the P point or the Q point by detecting any one of such differences. Of course, two or more may be used together to improve accuracy. The difference in the slope of the first part of the above-mentioned curve is not always clear in the figure, but at the point P the curve P 0 shown by the chain line, and at the point Q near the B axis which is the vertical axis of the solid hysteresis loop curve. Comparing the slopes of, it is clear that point Q is larger. This slope is called the biased magnetic permeability at the position of the hysteresis loop. The eddy current components included in the curves P 1 and Q 1 are also affected by this biased magnetic permeability, and as a result, the above-mentioned result is obtained in the first part of the hysteresis loop when a positive voltage is applied. Become. However, when the voltage changes rapidly with time, the effect of eddy current becomes large,
In both cases, the inclination of the first part is so small that it tends to be difficult to distinguish.
【００２１】図１に示すようにパルス発生器４によるパ
ルス電圧の印加は変圧器１の巻線１１の端子に直接印加
する方法を採用したものであるが、実際の変圧器の巻線
の定格電圧には非常に高いのものがあるし、パルス発生
器４を接続するのには困難な場合もある。図３はこの発
明の別の実施例を示す変圧器鉄心の模式的な斜視図あ
る。この図において、巻線１１と１３とを別の鉄心１２
の鉄心脚に巻回した構成を示してあるが、周知のように
これらは同じ鉄心脚に巻回されるのが実際である。鉄心
１２に前述の巻線１１，１３の他に電圧印加コイル５１
と検出コイル５２の２つのコイルからなる測定用コイル
５を設けてある。電圧印加コイル５１にはパルス発生器
４が接続されてパルス電圧が印加され、検出コイル５２
は電圧測定器に接続されて誘起電圧が測定される。電圧
印加コイル５１の巻数はパルス発生器４の発生電圧に適
した値が採用され、検出コイル５２の巻数はコンデンサ
などによる分圧が不要な電圧測定に適した値に設定され
ている。巻線１１を使用する場合と同じように、電圧印
加コイル５１と検出コイル５２とを共通にして１つのコ
イルからなる測定用コイル５とすることも可能である。As shown in FIG. 1, the pulse voltage is applied by the pulse generator 4 directly to the terminals of the winding 11 of the transformer 1, but the actual rating of the winding of the transformer is used. Some voltages are very high, and connecting the pulse generator 4 may be difficult. FIG. 3 is a schematic perspective view of a transformer core showing another embodiment of the present invention. In this figure, windings 11 and 13 are separated from each other by an iron core 12
However, as is well known, they are actually wound on the same iron core leg. In addition to the windings 11 and 13 described above, a voltage application coil 51 is provided on the iron core 12.
The measuring coil 5 including the two coils, ie, the detecting coil 52 and the detecting coil 52 is provided. The pulse generator 4 is connected to the voltage application coil 51 to apply the pulse voltage, and the detection coil 52
Is connected to a voltage measuring device and the induced voltage is measured. The number of turns of the voltage application coil 51 is set to a value suitable for the voltage generated by the pulse generator 4, and the number of turns of the detection coil 52 is set to a value suitable for voltage measurement that does not require voltage division by a capacitor or the like. Similar to the case where the winding 11 is used, the voltage application coil 51 and the detection coil 52 can be commonly used as the measurement coil 5 composed of one coil.
【００２２】これらの測定用コイル５の巻回位置はこの
図では上部継鉄に巻回した図を示してあるが、巻線１１
や１３が巻回される鉄心脚の上部又は下部の巻線１１や
１３とは離れた位置にに設ける構成が実際には採用され
る。図４はこの発明の別の実施例を示す鉄心１２の模式
的な斜視図、図５は磁気センサの斜視図である。これら
の図において、鉄心１２の磁束の流れる方向に沿って磁
気的に近接して磁気センサ７を設けたものである。磁気
センサ７は強磁性棒７０、これに巻回された測定用コイ
ル７１からなっており、測定用コイル７１は電圧印加コ
イル７１１と及び検出コイル７１２とからなっている。The winding position of these measuring coils 5 is shown in this drawing as being wound on the upper yoke, but the winding 11
In practice, a configuration is provided in which the cores 13 and 13 are provided at positions apart from the windings 11 and 13 on the upper or lower part of the iron core leg. FIG. 4 is a schematic perspective view of an iron core 12 showing another embodiment of the present invention, and FIG. 5 is a perspective view of a magnetic sensor. In these figures, the magnetic sensor 7 is provided magnetically close to the magnetic flux along the direction of the magnetic flux of the iron core 12. The magnetic sensor 7 includes a ferromagnetic rod 70 and a measuring coil 71 wound around the ferromagnetic rod 70. The measuring coil 71 includes a voltage applying coil 711 and a detecting coil 712.
【００２３】鉄心１２が励磁されると励磁の方向に平行
して設けられている強磁性棒７０も同じ磁界強度Ｈで励
磁される。したがって、変圧器１が電力系統に接続され
て運転状態にあるときには強磁性棒７０も交流励磁され
てヒステリシスループを描いている。変圧器１が系統か
ら切り離されると磁界強度Ｈが零になって、鉄心１２と
同様に強磁性棒７０もヒステリシスループのＢ軸を切る
点で止まりその位置の磁束密度である残留磁束を持つこ
とになる。When the iron core 12 is excited, the ferromagnetic rod 70 provided in parallel with the exciting direction is also excited with the same magnetic field strength H. Therefore, when the transformer 1 is connected to the electric power system and is in an operating state, the ferromagnetic rod 70 is also AC-excited and draws a hysteresis loop. When the transformer 1 is disconnected from the system, the magnetic field strength H becomes zero, and like the iron core 12, the ferromagnetic rod 70 also stops at a point that cuts the B axis of the hysteresis loop and has a residual magnetic flux that is the magnetic flux density at that position. become.
【００２４】この状態の磁気センサ７において、電圧印
加コイル７１にパルス発生器を接続してパルス電圧を印
加するとともにその電流を測定し、一方、強磁性棒７０
に生ずる磁束によって誘起される電圧を検出コイル７２
を用いて測定する。その結果は前述の図２を基に説明し
たことと同じである。ただ、強磁性棒７０の断面積は鉄
心１２に比べてはるかに小さくできるのでこれに用いる
パルス発生器の容量を図１のパルス発生器４に比べては
るかに小さくすることができるという特長がある。な
お、強磁性棒７０の材質は必ずしも鉄心１２と同じもの
である必要はない。例えば、フェライト製でもよい。In the magnetic sensor 7 in this state, a pulse generator is connected to the voltage applying coil 71 to apply a pulse voltage and measure its current, while the ferromagnetic rod 70 is used.
The voltage induced by the magnetic flux generated in the detection coil 72
Is measured. The result is the same as that described based on FIG. 2 described above. However, since the cross-sectional area of the ferromagnetic rod 70 can be made much smaller than that of the iron core 12, the capacity of the pulse generator used for this can be made much smaller than that of the pulse generator 4 of FIG. . The material of the ferromagnetic rod 70 does not necessarily have to be the same as that of the iron core 12. For example, it may be made of ferrite.
【００２５】図２で説明したようにＱ点において正極性
のパルス電圧を印加するとΔＢだけ上に移動する。した
がって、これを繰り返すと最初Ｑ点にあった残留磁束は
その値の絶対値が漸次減少し更に原点を越えて正の残留
磁束となり、ついにはＰ点に接近する。したがって、最
初の残留磁束の値がどうであっても正極性のパルス電圧
を繰り返し印加することによって常にＰ点に移動させる
ことができることになる。As described with reference to FIG. 2, when a positive pulse voltage is applied at point Q, it moves upward by ΔB. Therefore, when this is repeated, the absolute value of the residual magnetic flux at the point Q at the beginning is gradually reduced, and further exceeds the origin to become a positive residual magnetic flux, and finally approaches the point P. Therefore, regardless of the initial residual magnetic flux value, it is possible to always move to the point P by repeatedly applying the positive pulse voltage.
【００２６】このような現象を利用することによって鉄
心１２の残留磁束を常に一定の状態にすることができ
る。その状態に対して最適の位相で電源投入することに
よって励磁突流を抑制する位相投入方式とすることがで
きる。なお、これまでは全て単相の変圧器について説明
したが、励磁突流が特に問題になる大容量の変圧器の殆
どは３相器であり、その場合には、各相それぞれごとに
パルス電圧を印加して３本の鉄心脚ごとの残留磁束を求
めたり所定の残留磁束に設定したりすることになる。ま
た、測定コイル５や磁気センサ７も各鉄心脚に設けるこ
とになる。三相三脚鉄心の場合には各相の磁束の総和は
常に零なので１相分を省略することも可能である。By utilizing such a phenomenon, the residual magnetic flux of the iron core 12 can always be kept constant. It is possible to adopt a phase closing method that suppresses the exciting surge by turning on the power at the optimum phase for that state. Although all the single-phase transformers have been described so far, most of the large-capacity transformers in which the magnetizing surge is a particular problem are three-phase transformers. In that case, pulse voltage is applied to each phase. The residual magnetic flux for each of the three core legs is applied to obtain the residual magnetic flux or set to a predetermined residual magnetic flux. Further, the measuring coil 5 and the magnetic sensor 7 are also provided on each iron core leg. In the case of a three-phase tripod core, the total magnetic flux of each phase is always zero, so it is possible to omit one phase.
【００２７】[0027]
【発明の効果】この発明は前述のように、パルス電圧を
印加しその印加電圧と流入電流を測定しこれを基に変圧
器鉄心の残留磁束とこれに応じた投入位相を求め、この
投入位相に基づいて変圧器を電力系統に位相投入するこ
とによって励磁突流を抑制する効果が得られる。また、
単極性のパルス電圧を変圧器に印加して残留磁束をあら
かじめ定めてある所定の値まで変化させ、その値に応じ
た投入位相に基づいて変圧器を電力系統に位相投入する
ことによっても励磁突流を抑制する効果が得られる。As described above, according to the present invention, the pulse voltage is applied, the applied voltage and the inflow current are measured, the residual magnetic flux of the transformer core and the closing phase corresponding to the residual magnetic flux are calculated based on the measured voltage, and the closing phase is calculated. Based on the above, the effect of suppressing the magnetizing rush current can be obtained by injecting the phase of the transformer into the power system. Also,
Exciting rush current can also be obtained by applying a unipolar pulse voltage to a transformer to change the residual magnetic flux to a predetermined value, and then phase-injecting the transformer into the power system based on the closing phase according to that value. The effect of suppressing is obtained.
【図１】この発明の実施例を示す変圧器励磁突流抑制装
置を示す回路図FIG. 1 is a circuit diagram showing a transformer excitation surge suppressor showing an embodiment of the present invention.
【図２】図１においてパルス電圧が印加されたときのヒ
ステリシスループの図FIG. 2 is a diagram of a hysteresis loop when a pulse voltage is applied in FIG.
【図３】この発明の別の実施例を示す変圧器鉄心の模式
的な斜視図FIG. 3 is a schematic perspective view of a transformer core showing another embodiment of the present invention.
【図４】この発明の図３とは別の実施例を示す変圧器鉄
心の模式的な斜視図FIG. 4 is a schematic perspective view of a transformer core showing an embodiment different from FIG. 3 of the present invention.
【図５】図４の磁気センサの斜視図5 is a perspective view of the magnetic sensor of FIG.
【図６】励磁突流発生の説明図としての回路図FIG. 6 is a circuit diagram as an explanatory diagram of the generation of an exciting rush current.
【図７】励磁突流発生の説明図としての波形図FIG. 7 is a waveform diagram as an explanatory diagram of the excitation rush current generation.
【図８】変圧器鉄心のヒステリシスループの図FIG. 8 Diagram of hysteresis loop of transformer core
１ 変圧器 １１ 巻線 １２ 鉄心 １３ 巻線 ２ 電圧測定器 ３ 電流測定器 ４ パルス発生器 ５ 測定コイル ５１ 電圧印加コイル ５２ 検出コイル ７ 磁気センサ ７０ 強磁性棒 ７１ 電圧印加コイル ７２ 検出コイル 1 Transformer 11 Winding 12 Iron Core 13 Winding 2 Voltage Measuring Device 3 Current Measuring Device 4 Pulse Generator 5 Measuring Coil 51 Voltage Applying Coil 52 Detecting Coil 7 Magnetic Sensor 70 Ferromagnetic Rod 71 Voltage Applying Coil 72 Detection Coil
Claims (7)
加し、このときの印加電圧と流入電流を測定し、これら
を演算器に入力して変圧器の残留磁束を演算するととも
に、この残留磁束演算値に基づいて励磁突流を抑制する
投入位相を演算し、この演算結果に基づいて変圧器を電
源投入することを特徴とする変圧器励磁突流抑制方法。1. A pulsed voltage is applied to a voltageless transformer, the applied voltage and inflow current at this time are measured, and these are input to a calculator to calculate the residual magnetic flux of the transformer. A method for suppressing a magnetizing surge of a transformer, characterized in that a closing phase for suppressing a magnetizing surge is calculated based on the residual magnetic flux calculation value, and the transformer is powered on based on the calculation result.
加するパルス電源、この印加電圧を測定する電圧測定
器、流入電流を測定する電流測定器、電圧と電流の測定
値が入力されて変圧器の残留磁束とこれを基にした励磁
突流を抑制する投入位相を演算する投入位相演算器及び
この演算された投入位相に基づいて変圧器を電源に投入
する投入器からなることを特徴とする変圧器励磁突流抑
制装置。2. A pulsed power source for applying a pulsed voltage to a transformer in a non-voltage state, a voltage measuring device for measuring the applied voltage, a current measuring device for measuring inflow current, and a measured value of voltage and current are input. And a closing phase calculator for calculating a closing phase for suppressing the residual magnetic flux of the transformer and the exciting rush current based on the residual magnetic flux of the transformer, and a closing device for turning on the transformer based on the calculated closing phase. Transformer excitation current surge suppressor.
を印加することによって、変圧器の残留磁束を所定の値
に設定し、設定された残留磁束に応じた励磁突流を抑制
する投入位相に基づいて変圧器を電源投入することを特
徴とする変圧器励磁突流抑制方法。3. A residual magnetic flux of the transformer is set to a predetermined value by applying a unipolar pulse voltage to the transformer in the no-voltage state, and an excitation surge is suppressed to suppress the exciting magnetic rush current according to the set residual magnetic flux. A method for suppressing transformer magnetizing surge current, characterized in that the transformer is powered on based on the phase.
を印加するパルス電源、あらかじめ設定された所定の残
留磁束に応じた励磁突流を抑制する投入位相に基づいて
変圧器を系統に投入する投入器からなり、前記所定の残
留磁束になるよう少なくとも１回パルス電源によって変
圧器を励磁することを特徴とする変圧器励磁突流抑制装
置。4. A pulse power supply for applying a unipolar pulse voltage to a transformer in a no-voltage state, and a transformer is applied to the system based on a closing phase that suppresses an exciting rush current according to a predetermined residual magnetic flux set in advance. A transformer excitation surge current suppression device, characterized in that the transformer excites the transformer at least once by a pulse power source so as to obtain the predetermined residual magnetic flux.
の端子が外部に引き出されてなり、この端子にパルス発
生器によるパルス電圧を印加することを特徴とする請求
項１，２，３又は４記載の変圧器励磁突流抑制方法又は
その装置。5. A transformer according to claim 1, wherein a measuring coil is wound around an iron core of the transformer and its terminal is pulled out to the outside, and a pulse voltage from a pulse generator is applied to this terminal. 3. The transformer excitation surge current suppression method or device thereof according to 3 or 4.
センサを変圧器の鉄心に磁気的に近接して設け、この測
定用コイルにパルス電圧を印加して印加電圧と流入電流
を測定し、これらを演算器に入力して間接的に変圧器の
残留磁束を演算するとともに、残留磁束演算値に基づい
て励磁突流を抑制する投入移相を演算し、この演算結果
に基づいて変圧器を電源投入することを特徴とする変圧
器励磁突流抑制方法。6. A magnetic sensor, in which a measuring coil is wound around a ferromagnetic rod, is provided magnetically close to an iron core of a transformer, and a pulse voltage is applied to the measuring coil to apply an applied voltage and an inflow current. Measure these values and input them to the calculator to indirectly calculate the residual magnetic flux of the transformer, and also calculate the closing phase shift that suppresses the magnetizing rush current based on the residual magnetic flux calculation value. A method for suppressing a transformer-excited surge current, which is characterized in that the power is turned on.
た強磁性棒に測定用コイルが巻回された磁気センサ、測
定用コイルにパルス電圧を印加するパルス電源、測定用
コイルの印加電圧を測定する電圧測定器、流入電流を測
定する電流測定器、これらの電圧、電流が入力されて変
圧器の残留磁束とこれを基にした励磁突流を抑制する投
入位相を演算する投入位相演算器、この演算された投入
位相に基づいて変圧器を電源に投入する投入器からな
り、変圧器を電源に投入する前に、パルス電源によって
検出コイルにパルス電圧を印加することを特徴とする変
圧器励磁突流抑制装置。7. A magnetic sensor in which a measuring coil is wound around a ferromagnetic rod provided magnetically close to an iron core of a transformer, a pulse power source for applying a pulse voltage to the measuring coil, and a measuring coil. A voltage measuring device that measures the applied voltage, a current measuring device that measures the inflow current, and a closing phase that inputs these voltages and currents and calculates the closing phase that suppresses the residual magnetic flux of the transformer and the exciting rush current based on it. It is composed of a calculator and a charger for charging the transformer to the power supply based on the calculated closing phase, and is characterized in that the pulse voltage is applied to the detection coil by the pulse power supply before the transformer is switched to the power supply. Transformer excitation surge suppressor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5044196A JPH06261444A (en) | 1993-03-05 | 1993-03-05 | Method and equipment for suppressing exciting rush current of transformer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5044196A JPH06261444A (en) | 1993-03-05 | 1993-03-05 | Method and equipment for suppressing exciting rush current of transformer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH06261444A true JPH06261444A (en) | 1994-09-16 |
Family
ID=12684826
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5044196A Pending JPH06261444A (en) | 1993-03-05 | 1993-03-05 | Method and equipment for suppressing exciting rush current of transformer |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH06261444A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100624496B1 (en) * | 2004-06-22 | 2006-09-19 | (주)드림파워텍 | electric current prevention system and the control method of transformer |
| KR100945721B1 (en) * | 2008-04-30 | 2010-03-08 | 성균관대학교산학협력단 | Apparatus for Decreasing Inrush Current Using SFCL, and Decision Method for Optimum Resistance thereof |
-
1993
- 1993-03-05 JP JP5044196A patent/JPH06261444A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100624496B1 (en) * | 2004-06-22 | 2006-09-19 | (주)드림파워텍 | electric current prevention system and the control method of transformer |
| KR100945721B1 (en) * | 2008-04-30 | 2010-03-08 | 성균관대학교산학협력단 | Apparatus for Decreasing Inrush Current Using SFCL, and Decision Method for Optimum Resistance thereof |
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