JP2008048507A - Connecting method of induction generator, induction generator system and blocker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently use blockers in order to limit a rush current in the case of connecting an induction generator to a power system without using a reactor. <P>SOLUTION: This induction generator system 100 is connected to a power transmission line 10, and includes the blockers 1, 2, a timer 9 and an induction generator IG. The power transmission line 10 is a three-phase power transmission line, and composed of power transmission lines 10a, 10b and 10c. The blocker 1 includes connecting points 3, 4 and 5. The blocker 2 includes connecting points 6, 7 and 8. Terminals Ta, Tb and Tc are arranged at the induction generator IG. The terminals Ta, Tb and Tc are connected to the power transmission lines 10a, 10b and 10c, respectively, via the blocker 1 or the blocker 2. Each connecting point is in an open state at an initial stage, but when the induction generator IG is connected to the power transmission line 10, the connecting points 3, 4 and 5 are closed by the operation of the blocker 1 which is firstly conducted, and the connecting points 6, 7 and 8 are closed by the operation of the blocker 2 which is conducted after the lapse of a prescribed time by the control of the timer 9. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an induction generator connection method for connecting an induction generator to an electric power system, an induction generator system, and a circuit breaker.

  Conventionally, when an induction generator is connected to a power transmission line that is a power system, a large amount of inrush current (excitation current) flows to the induction generator and the voltage of other devices connected in the vicinity of the connection point decreases. Doing so may affect customers who use the device. Therefore, measures are taken to limit the inrush current from the transmission line. For example, when starting an induction generator, connect a reactor in series between the transmission line and the induction generator to limit the inrush current, and after the induction generator has accelerated to a steady state, There is a method of short-circuiting the reactor in order to apply the entire voltage from the induction generator to the transmission line.

  FIG. 3 is a diagram illustrating a change in the current flowing through the induction generator when the induction generator is connected to the transmission line. When an induction generator is connected to a power transmission line, first, the induction generator receives an excessive inrush current and starts rotating as an electric motor. When the current gradually decreases and reaches the rated current, the induction generator enters a steady operation as an original generator. Here, a configuration example using a reactor to limit the inrush current will be described.

  FIG. 4 is a diagram illustrating a configuration example of a conventional induction generator system. The induction generator system 200 is connected to a three-phase power transmission line 10 and includes circuit breakers 11 and 12 for each phase, a reactor L, a switch SW (hereinafter collectively referred to as equipment), and an induction generator IG. . A device is connected to the power transmission line 10 of each phase, and an induction generator IG is further connected to the device of each phase. As a device connection configuration between the power transmission line 10 and the induction generator IG, first, the circuit breaker 11 and the reactor L are connected in series. This limits the overcurrent exceeding a predetermined value by the circuit breaker 11 and limits the alternating current flowing from the power transmission line 10 to the induction generator IG by the reactor L to a predetermined ratio. Further, the switch SW and the circuit breaker 12 connected in series are connected in parallel to the reactor L. This is because when the current flowing through the induction generator IG reaches the rated current, by closing the switch SW that was initially open, the reactor L can be short-circuited and the entire voltage from the induction generator can be applied to the transmission line. At the same time, the circuit breaker 12 limits overcurrent exceeding a predetermined value. In some embodiments, such a configuration allows a voltage drop of about 14%.

Patent Document 1 discloses a wind turbine generator in which another input control circuit is provided instead of the reactor.
JP-A-5-199800

  However, when using a reactor as described above, it is necessary to install a reactor of a predetermined size in order to limit the inrush current at the moment when the induction generator is connected to the transmission line. There is a problem of being uneconomical from the viewpoint. In addition, two circuit breakers are used to connect to a one-phase power transmission line. However, since one circuit breaker is connected in parallel to the reactor, it is substantially 1 for inrush current. There is a problem of inefficiency because there is only a cut-off capacity for the vehicle.

  This invention is made | formed in view of the said subject, and mainly uses a circuit breaker without using a reactor, in order to restrict | limit the inrush current at the time of connecting an induction generator to an electric power grid | system. Objective.

In order to solve the above-mentioned problem, the present invention is an induction generator connection method in which an induction generator is connected to a three-phase power system by a circuit breaker, and the circuit breaker is included in the three-phase power system, A first step of connecting the induction generator to a two-phase power system, and the circuit breaker after the predetermined time has elapsed from the first step, the three-phase power system other than the two-phase And a second step of bringing the induction generator into conduction with the one-phase power system.
According to this method, instead of connecting the induction generator to the three-phase power system at a time, first the connection to the two-phase power system is made, and then the connection to the remaining one-phase power system after the current has stabilized. I do.

In addition, the present invention is an induction generator system, wherein when the induction generator is connected to an induction generator and a three-phase power system, the two-phase power system is included in the three-phase power system. After the induction generator is made conductive, the circuit breaker is configured to include a circuit breaker that makes the induction generator conductive to a one-phase power system other than the two-phase among the three-phase power system. To do.
According to this configuration, instead of connecting the induction generator to the three-phase power system at a time, first the connection to the two-phase power system is performed, and then the connection to the remaining one-phase power system is performed. .

Moreover, this invention is an induction generator system, Comprising: After the predetermined time passes after the said circuit breaker makes the said induction generator conduct | electrically_connect to the said 2 phase electric power system, the said circuit breaker is other than the said 2 phase. It further comprises a timer for controlling the induction generator to conduct to a one-phase power system.
According to this configuration, the connection to the two-phase power system is performed, and then the connection to the remaining one-phase power system is performed after the current is stabilized.

Further, the present invention is a circuit breaker, and when an induction generator is connected to a three-phase power system, the induction generator is conducted to a two-phase power system among the three-phase power systems. Then, the induction generator is connected to a one-phase power system other than the two-phase power system among the three-phase power systems.
According to this configuration, instead of connecting the induction generator to the three-phase power system at a time, first the connection to the two-phase power system is performed, and then the connection to the remaining one-phase power system is performed. .

  In addition, the problems disclosed in the present application and the solutions thereof will be clarified by the description of the best mode for carrying out the invention and the drawings.

  According to the present invention, it is possible to efficiently use a circuit breaker without using a reactor in order to limit an inrush current when an induction generator is connected to an electric power system.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. The induction generator system according to the embodiment of the present invention uses a circuit breaker to first conduct the induction generator in two phases of a three-phase transmission line (power system), and after a predetermined time has elapsed. The induction generator is connected to the remaining one phase. According to this, when limiting the inrush current at the time of connecting an induction generator to a power transmission line, a circuit breaker can be used efficiently, without using a reactor.

<< System configuration and operation >>
FIG. 1 is a diagram illustrating a configuration example of an induction generator system according to an embodiment of the present invention. The induction generator system 100 is connected to the power transmission line 10 and includes the circuit breakers 1 and 2, a timer 9, and an induction generator IG. The power transmission line 10 is a three-phase power transmission line and includes power transmission lines 10a, 10b, and 10c. The circuit breaker 1 includes contacts 3, 4 and 5. The circuit breaker 2 includes contacts 6, 7 and 8. The circuit breakers 1 and 2 are realized by a CB (Circuit Breaker) or the like. The timer 9 controls the time interval between the operation of the circuit breaker 1 and the operation of the circuit breaker 2. The induction generator IG is provided with terminals Ta, Tb and Tc. Terminals Ta, Tb, and Tc are connected to power transmission lines 10a, 10b, and 10c through circuit breakers 1 and 2, respectively.

  The contact is a switch that is between the power transmission line 10 and the induction generator IG and controls whether or not a current flows in a predetermined direction. All of the contacts are initially open, but when the induction generator IG is connected to the transmission line 10, the contacts 3, 4 and 5 are closed by the operation of the circuit breaker 1 performed first, The contacts 6, 7 and 8 are closed by the operation of the circuit breaker 2 performed after the elapse of a predetermined time. The operation of the circuit breaker 2 after a predetermined time from the operation of the circuit breaker 1 is controlled by the timer 9. According to this, between the power transmission line 10 and the induction generator IG, first, the connection for two phases is performed, and then the remaining one phase is connected after the current is stabilized. Can be reduced, and a voltage drop in the vicinity can be prevented. Each contact has a circuit breaker characteristic. When an overcurrent exceeding a predetermined value flows, the contact is opened to interrupt the overcurrent.

  In the circuit breaker 1, the contact 3 controls the current flowing from the power transmission line 10a to the terminal Ta of the induction generator IG. The contact 4 controls the current flowing from the terminal Ta to the power transmission line 10a. The contact 5 controls the current flowing from the power transmission line 10b to the terminal Tb. When the contacts 3, 4 and 5 are closed, the connection between the power transmission line 10a and the terminal Ta and the connection between the power transmission line 10b and the terminal Tb are established, so that the connection for two phases is performed.

  In the circuit breaker 2, the contact 6 controls the current flowing from the terminal Tb of the induction generator IG to the power transmission line 10b. The contact 7 controls the current flowing from the power transmission line 10c to the terminal Tc. The contact 8 controls the current flowing from the terminal Tc to the power transmission line 10c. When the contacts 6, 7, and 8 are further closed while the contacts 3, 4, and 5 are closed, the connection between the power transmission line 10c and the terminal Tc is newly conducted, and the connection for the remaining one phase is performed. It will be.

≪System effect≫
When connecting the induction generator IG to the power transmission line 10, the three phases are not connected at once, but the two phases are connected in advance, and the remaining one phase is connected after a predetermined time. According to this, it is possible to obtain the same current limiting effect as when the reactor is used without extremely reducing the voltage. The details will be described below.

  FIG. 2 is a diagram illustrating a voltage phase vector by the power transmission line 10 and a voltage applied between terminals of the induction generator IG. FIG. 2A shows the voltage applied between the terminals of the induction generator IG when three phases are connected at once. Here, Va, Vb, and Vc indicate voltage phase vectors (hereinafter, also referred to as vectors) of the power transmission lines 10a, 10b, and 10c, respectively. Further, the impedance of the circuit breaker 1 or 2 between the power transmission line 10a and the terminal Ta, the power transmission line 10b and the terminal Tb, and the power transmission line 10c and the terminal Tc is 10 [Ω], and the impedance (restraint) of the induction generator IG itself is Impedance) is set to 20 [Ω] (the same applies to FIGS. 2B and 2C). When the circuit breakers 1 and 2 are not provided, the voltage between the terminals of the induction generator IG is 1 [V] (= | Va−Vb | = | Vb−Vc | = | Vc−Va |) (FIG. 2 (b) and (c) are the same). Further, A1, A2, and A3 indicate the magnitudes of voltages between the terminals.

In the case of the impedance value, the phase vector of the voltage applied to each terminal of the induction generator IG is 2/3 (= 20 / (10 + 20)) of the vector of each transmission line. Therefore, the average voltage of the three phases is obtained by the following formula 1.

  According to this, when three phases are connected at once, it is considered that the voltage drops by about 33%.

FIG. 2B shows the voltage applied between the terminals of the induction generator IG when two phases are connected in advance. B1, B2 and B3 indicate the magnitude of the voltage between the terminals. In this case, the phase vector of the voltage applied to the terminals Ta and Tb is 2/3 of the vector of each transmission line, but the phase vector of the voltage applied to the terminal Tc is the same as the vector Vc of the transmission line 10c. Therefore, the average voltage of the three phases is obtained by the following equation 2.

  According to this, when the two phases are connected in advance, it is considered that the voltage drop is about 22%, so that the voltage drop can be suppressed compared to the case where the three phases are connected at once. it can.

FIG. 2C shows the voltage applied between the terminals of the induction generator IG when the remaining one phase is connected. C1, C2, and C3 indicate the magnitudes of voltages between the terminals. In this case, the phase vector of the voltage applied to the terminals Ta and Tb is the same as the vector of each transmission line, but the phase vector of the voltage applied to the terminal Tc is 2/3 of the vector Vc of the transmission line 10c. Accordingly, the average voltage of the three phases is obtained by the following equation 3.

  According to this, when the remaining one phase is connected, the voltage drop is considered to be about 11%, so that the voltage drop can be suppressed compared to the case where three phases are connected at a time. .

  According to the embodiment of the present invention described above, the induction generator IG is connected to the three-phase power transmission line 10 divided into the two-phase power transmission lines 10a and 10b and the remaining one-phase power transmission line 10c. Therefore, an extreme voltage drop when the induction generator IG is connected to the three-phase power transmission lines 10a, 10b, and 10c at a time can be suppressed, and the inrush current can be appropriately limited. Also, by using the breakers 1 and 2 at the same time, the total breaking capacity of the two breakers 1 and 2 becomes the total breaking capacity, so the breaking capacity of each breaker 1 and 2 is small. Also good.

  According to this, the inrush current can be appropriately limited without using an economical reactor from the viewpoint of price and space. In addition, the circuit breaker can be efficiently used and realized with a simple configuration, which is economical.

  Although the best mode for carrying out the present invention has been described above, the above embodiment is intended to facilitate understanding of the present invention and is not intended to limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and equivalents thereof are also included in the present invention.

It is a figure which shows the structural example of the induction generator system which concerns on embodiment of this invention. It is a figure which shows the phase vector of the voltage by a power transmission line, and the voltage concerning between the terminals of an induction generator, (a) shows the case where three phases are connected at once, (b) shows two phases ahead. The case where it connects is shown, (c) shows the case where the remaining one phase is connected. It is a figure which shows the change of the electric current which flows into an induction generator at the time of connecting an induction generator to a power transmission line. It is a figure which shows the structural example of the conventional induction generator system.

Explanation of symbols

100 induction generator system 1, 2, circuit breaker 3, 4, 5, 6, 7, 8 contact 9 timer IG induction generator Ta, Tb, Tc terminal 10, 10a, 10b, 10c Transmission line (power system)

Claims (4)

An induction generator connection method for connecting an induction generator to a three-phase power system with a circuit breaker,
A first step of causing the circuit breaker to conduct the induction generator to a two-phase power system of the three-phase power system;
A second step in which the circuit breaker causes the induction generator to conduct to a one-phase power system other than the two-phase power system among the three-phase power systems after a predetermined time has elapsed from the first step; ,
An induction generator connection method comprising: An induction generator,
When the induction generator is connected to a three-phase power system, after the induction generator is conducted to a two-phase power system among the three-phase power system, among the three-phase power system, A circuit breaker for connecting the induction generator to a one-phase power system other than the two phases;
An induction generator system comprising:   After the predetermined time has elapsed after the circuit breaker has connected the induction generator to the two-phase power system, the circuit breaker connects the induction generator to a one-phase power system other than the two-phase power system. The induction generator system according to claim 2, further comprising a timer that controls the induction generator. When an induction generator is connected to a three-phase power system, after the induction generator is conducted to a two-phase power system in the three-phase power system, the three-phase power system The circuit breaker characterized by making the said induction generator conduct | electrically_connect to the electric power system of 1 phase other than 2 phases.

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