JP2014124048A - Power interchange device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power interchange device capable of interchanging power by working as a phase modulation facility that adjusts the voltage and reactive power in one of two systems separated from each other in a normal state, and interconnecting the other system that is not normally connected when an available power supply in the one system falls below load power.SOLUTION: There is provided a power interchange device comprising: a generator motor 3A which works as a motor and a generator by being connected to a system A; a generator motor 3B which rotates around a rotating shaft 9, which is the same as that of the generator motor 3A, and works as a motor and a generator by being connected to a system B; and a control device configured to operate the generator motors 3A, 3B as a variable-speed device. In a normal state, the generator motor 3A is connected to the system A and the generator motor 3B is separated from the system B, and the generator motor 3A works as a phase modulation means for adjusting reactive power. According to supply and demand conditions of the system A, the generator motor 3B is connected to the system B, such that power is transferred between the system A and the system B.

Description

  The present invention relates to a power interchange apparatus that performs power interchange between different power systems, and maintains the frequency of the small-scale power system network when an abnormality such as unplanned power loss occurs in the small-scale power system network, for example. The present invention relates to a power interchange apparatus that can be quickly connected to a large-scale power system.

  In recent years, as a means of utilizing renewable energy including natural energy such as solar power generation and wind power generation whose output is unstable, it is possible to maintain electric power at the local level and reduce the burden on the power transmission system. For example, micro grid, smart grid And other small-scale power grids (hereinafter referred to as small-scale grids) are being studied. This small-scale grid has power generation facilities that can follow the ever-changing photovoltaic power generation, wind power generation and load fluctuations, and these are necessary to maintain the power quality (frequency, voltage) of the entire small-scale grid. Supply and demand control of the equipment. In general, a system in which this small-scale network is always connected to a large-scale power system (hereinafter referred to as a large-scale system) and the power flow is kept constant by supply and demand control is generally used.

  As such a power interchange apparatus, there is a conventional one that controls the power flow between two different power systems as disclosed in, for example, Japanese Patent Application Laid-Open No. 59-127531 (Patent Document 1). . The power interchange device disclosed in Patent Document 1 converts the voltage and frequency of one commercial power supply by using a cycloconverter, and returns this power supply to another commercial power supply using the cycloconverter again. Thus, as shown in FIG. 13, a synchronous machine equipped with a flywheel for storing energy and dedicated to always-on power interchange is inserted between each cycloconverter.

  FIG. 13 shows a power interchange device disclosed in Patent Document 1. In FIG. 13, a symbol A indicates a first power system having a commercial frequency, and a symbol B indicates a second power system having a commercial frequency. The primary side of the three-phase main transformer 100A is connected to the first power system A, and similarly, the primary side of the three-phase main transformer 100B is connected to the second power system B. In addition, cycloconverters 101A and 101B are connected to the secondary side of the three-phase main transformers 100A and 100B for each line of the UV phase, the VW phase, and the WU phase, respectively. A synchronous machine 102 using a three-phase high frequency as a power source is connected between the cycloconverters 101A and 101B, and a flywheel 70 is mechanically connected to the rotary shaft 9 of the synchronous machine 102. In general, a cycloconverter uses a high-frequency AC power supply as an input, selects a waveform using a semiconductor switching element, and converts it to a low-frequency AC power supply. In the converters 101A and 101B, the relationship between the input and output of the general cycloconverter is reversed.

  In the conventional power interchange device disclosed in Patent Document 1, the input side of the cycloconverters 101A and 101B is connected to a low frequency AC power source as described above, and the output side is connected to a high frequency AC power source. ing. That is, the high-frequency three-phase high-frequency voltages 103A and 103B connected to the synchronous machine 102 are converted into the low-frequency (commercial frequency) single-phase AC voltages 104A and 104B. Here, the frequencies of the three-phase high-frequency voltages 103A and 103B are about 10 times the respective system frequencies.

This cycloconverter system is composed of two sets, the first system is connected to the first power system A, the second system is connected to the second power system B, and the first power system A side. To the second power system B side or the second power system B side to the first power system A side. The synchronous machine 102 rotates in synchronization with the three-phase high-frequency power supplies 103A and 103B, and the flywheel 70 is provided in response to a steep power demand on the side to be accommodated in power accommodation.

JP 59-127531 A

  The conventional power interchange device is a device that is always connected and dedicated to power interchange, and is always affected by both systems, and two sets of converters corresponding to the interchangeable power capacity and the effect of the other system are alleviated. It was a complicated and expensive device provided with a flywheel composed of a rotating machine. Further, as described above, the power converter using a semiconductor is used, and there is a problem that a short-time overload cannot be allowed.

  The present invention has been made to solve the above-described problems, and can be operated and supplied as a phase-adjusting facility that adjusts the voltage and reactive power in one of the systems in a state where both systems are separated at all times. When the power is lower than the load power and it is necessary to receive power interchange, the purpose is to obtain a power interchange device that can be connected to the other system that is not connected at all times, and that can accommodate the determined power interchange It is.

A power interchange apparatus according to the present invention is connected to a first power system, rotates on the same rotating shaft as the first rotating machine, and operates as a second rotating machine that operates as an electric motor and a generator. A second rotating machine connected to the power system and operating as an electric motor and a generator, and a control device for operating the first and second rotating machines as a variable speed machine,
Normally, the first rotating machine is connected to the first power system, the second rotating machine is disconnected from the second power system, and the first rotating machine is connected to the first power system. It operates as a phase adjusting means for adjusting voltage and reactive power, and the second rotating machine is connected to the second power system according to the supply and demand situation of the first power system, and the first power system and the above Power is exchanged between the second power systems.

  According to the power interchange device according to the present invention, the two systems are normally separated and operated as a phase-adjusting facility that adjusts the voltage and reactive power in one system, and the power that can be supplied is less than the load power. When it is necessary to receive accommodation, it is connected to the other system which is not connected at all times, so that it is possible to exchange power.

It is a figure explaining the power interchange apparatus which concerns on Embodiment 1 of this invention. It is a figure explaining an example of the connection start condition detection circuit of the electric power accommodation apparatus which concerns on Embodiment 1 of this invention. It is a figure explaining the power interchange apparatus which concerns on Embodiment 2 of this invention. It is a figure explaining an example of the frequency control part of the power interchange apparatus which concerns on Embodiment 2 of this invention. It is a figure explaining the power interchange apparatus which concerns on Embodiment 3 of this invention. It is a figure explaining the power interchange apparatus which concerns on Embodiment 4 of this invention. It is a figure explaining the power interchange apparatus which concerns on Embodiment 5 of this invention. It is a figure explaining the power interchange apparatus which concerns on Embodiment 6 of this invention. It is a figure explaining the power interchange apparatus which concerns on Embodiment 7 of this invention. It is a figure explaining the power interchange apparatus which concerns on Embodiment 8 of this invention. It is a figure explaining the power interchange apparatus which concerns on Embodiment 9 of this invention. It is a figure explaining the power interchange apparatus which concerns on Embodiment 10 of this invention. It is a figure explaining the conventional power interchange apparatus.

  Embodiments of a power interchange apparatus according to the present invention will be described below with reference to the drawings. In addition, although the case where this invention is applied to the power interchange between a small-scale system network and a large-scale system is demonstrated, it is not limited to the power interchange between a small-scale system network and a large-scale system, Arbitrary 1st This is applicable to power interchange between the second power system and the second power system.

Embodiment 1 FIG.
FIG. 1 is a diagram for explaining a power interchange apparatus according to Embodiment 1 of the present invention. In FIG. 1, symbol A indicates a small-scale network, and symbol B indicates a large-scale system. Here, the device configuration connected to the small-scale system network A (hereinafter referred to as system A) is the same as the device configuration connected to the large-scale system B (hereinafter referred to as system B). The devices to be connected are indicated by “A”, and the devices connected to the system B are indicated by “B”.

  A main circuit breaker 1A and a step-up transformer 2A are connected to the system A, and a main circuit breaker 1B and a step-up transformer 2B are connected to the system B. The step-up transformers 2A and 2B are step-up transformers that step up the device voltage connected to the systems A and B to the system voltage, and include the synchronous circuit breakers 4A and 4B that incorporate the variable speed generator motors 3A and 3B into the system. The variable speed generator motors 3A and 3B are connected to the stators via the vias, respectively.

  The secondary excitation devices 5A and 5B branch to the secondary side of the step-up transformers 2A and 2B as a main circuit, and are connected to the input terminals via the excitation breakers 6A and 6B and the secondary excitation transformers 7A and 7B. Three-phase alternating current is input. The secondary excitation devices 5A and 5B use this three-phase alternating current as a power source to generate a variable-frequency three-phase alternating voltage, and alternating-current excite the rotors of the variable speed generator motors 3A and 3B. Reference numerals 8A and 8B denote starting stator short-circuit switches that are started when the variable speed generator motors 3A and 3B are stopped.

  The variable speed generator / motor 3A is mechanically connected to the variable speed generator / motor 3B by a rotating shaft 9. The system A side device is connected to the system A, and the system B side device is connected to the system B, respectively. The system is configured. Here, the main circuit converter of the secondary excitation devices 5A and 5B may be a converter that uses DC once, such as AC / DC / AC, or a converter that directly converts AC to AC.

  Reference numeral 10 denotes a host control device that performs monitoring of the entire system A, supply and demand control, status monitoring of the system B, etc., and transmits start / stop, operation mode of the device, and control command value to the operation control device 11. Then, the entire power interchange device is monitored, started and stopped, circuit breaker sequence control, and control mode adjustment.

  Voltage detection transformers 12A and 12B are connected to secondary sides of the step-up transformers 2A and 2B, and current detection transformers 13A and 13B as a variable speed system are connected. Further, sensors 14A and 14B for detecting the rotor phase θr and the rotation speed N, which are the states of the rotor, are attached to the rotors of the variable speed generator motors 3A and 3B. Specifically, a resolver, an encoder, or the like is used as the sensors 14A and 14B.

Reference numerals 15A and 15B denote excitation control devices. The excitation control devices 15A and 15B give the command values of the d-axis current command value id ^* and the q-axis current command value iq ^{* to} the secondary excitation devices 5A and 5B, The rotational speed, output voltage, active power, reactive power, and the like of the variable speed generator motors 3A and 3B are stably controlled to the command values, and are configured as follows.
That is, the excitation control devices 15A and 15B include active power detectors 16A and 16B, reactive power detectors 17A and 17B, voltage detectors 18A and 18B, rotation speed control units 19A and 19B, active power control units 20A and 20B, and invalidity. Power control units 21A and 21B, voltage control units 22A and 22B, q-axis signal selection units 23A and 23B, and d-axis signal selection units 24A and 24B are provided.
Here, regarding q-axis control in the A-side excitation control device 15A, when performing power control, the q-axis signal selection unit 23A selects the power control 20A side, and when performing rotation speed control, similarly selects the rotation speed control 19A side. To do. For d-axis control, the reactive power control 21A side is selected by the d-axis signal selection unit 24A when reactive power control is performed, and the voltage control 22A side is selected when performing voltage control.

The rotational speed control units 19A and 19B receive the rotational speed command value N ^* and the feedback signal N detected by the sensors 14A and 14B output from the rotational speed detectors 25A and 25B as inputs, and the active power control unit 20A. , 20B, reactive power control units 21A, 21B, and voltage control units 22A, 22B are active power detectors 16A, 16B, reactive power detectors 17A, 17B, and command values Pg ^* , Qg for voltage detectors 18A, 18B, respectively. ^* , Vg ^* and the feedback signal of each detected value are input, and it is configured by deviation calculation, PID control function, and the like.

Further, the q-axis signal selection units 23A and 23B are, based on commands from the operation control device 11, rotation speed control units 19A and 19B and active power control units that become q-axis current command values iq ^* for the secondary excitation devices 5A and 5B. The outputs of 20A and 20B are selected, and the d-axis signal selection units 24A and 24B are reactive power control units 21A that become d-axis current command values id ^* for the secondary excitation devices 5A and 5B according to commands from the operation control device 11. , 21B and the outputs of the voltage control units 22A, 22B are selected. In the case of a control device using variable speed generator motors 3A and 3B as a rotating machine, operation is normally performed within an allowable operating range such as active power, reactive power, voltage, variable speed width (allowable slip frequency width) deviation prevention, etc. However, the description is omitted here.

  The power interchange apparatus according to Embodiment 1 is configured as described above, and the operation thereof will be described next. In order to operate the variable speed system on the system A side as the phase adjusting equipment from the stop state in which the main circuit breakers 1A and 1B, the synchronous circuit breakers 4A and 4B, and the excitation circuit breakers 6A and 6B shown in FIG. It can be done in the next step.

(1) The starting stator short circuit switch 8A is closed, the main circuit breaker 1A of the step-up transformer 2A is turned on, and the excitation breaker 6A of the secondary excitation device 5A is turned on.
(2) After that, when the secondary excitation device 5A is activated and the rotor of the variable speed generator-motor 3A is AC-excited, a rotating magnetic field is generated in the rotor. This rotating magnetic field generates electromagnetic force and torque in the stator, and the rotor starts to rotate.
(3) When the AC secondary excitation frequency of the rotor of the variable speed generator-motor 3A reaches a frequency at which a rotational speed higher than the rotor synchronization speed is obtained, the excitation of the secondary excitation device 5A is stopped, and then The starting stator short circuit switch 8A is opened.

(4) Thereafter, the secondary excitation device 5A is activated again. The rotational speed of the variable speed generator-motor 3A gradually decreases by opening the stator, but the stator voltage of the variable-speed generator motor 3A is applied by applying an alternating magnetic field that is the difference between the rotational speed and the synchronous speed from the secondary excitation device 5A. The phase is synchronized with the system A, and the synchronous circuit breaker 4A is turned on at the coincidence.
(5) When the variable speed system on the system A side is operated as the phase adjusting equipment, the q axis control is selected from the operation control device 11 by the q control of the excitation control device 15A in order to maintain the rotation speed of the variable speed generator motor 3A. A signal for selecting the rotation speed control unit 19A is given to the unit 23A.
Specifically, the rated rotational speed is set to the rotational speed command value N ^* , and the rotational speed signal is obtained by the rotational speed detector 25A based on the signal of the sensor 14A directly connected to the rotating shaft 9. This signal is fed back to the rotational speed control unit 19A, and the deviation from the rotational speed command value N ^* enters the PID control function unit to become a q-axis current command value iq ^* signal to the secondary excitation device 5A. When the secondary excitation device 5A controls the q-axis current to the q-axis current command value iq ^* signal, the input power of the variable speed generator-motor 3A changes and the rotational speed is adjusted to the command value N ^*. .

(6) In addition, here, the operation is as a phase adjusting facility, and the d-axis control is performed by the d-axis signal selection unit of the excitation control device 15A via the operation control device 11 from the host control device 10 according to the situation of the system A. A signal for selecting the voltage control unit 22A or the reactive power control unit 21A is given to 24A. When voltage control is selected, the deviation signal between the feedback signal of the detection value from the voltage detector 18A and the voltage command value Vg ^* from the host controller 10 is selected by the voltage control unit 22A, and is invalid when reactive power control is selected. The deviation signal between the feedback signal of the detected value from the reactive power detector 17A and the reactive power command value Qg ^* from the host controller 10 is supplied to the secondary excitation device 5A via the respective PID control functions by the power controller 21A. It is given as a control signal for the shaft current command value id ^* .

  As described above, the variable speed system on the system A side can be operated as a phase adjusting facility. The variable speed system on the system B side in this state is the main circuit breaker 1B, although the variable speed generator motor 3B attached to the same shaft as the variable speed generator motor 3A of the variable speed system on the system A side is rotating. The synchronous circuit breaker 4B and the excitation circuit breaker 6B are open, disconnected from the system B, and the secondary excitation device 5B is also stopped.

  Next, the operation when the power that can be supplied by the system A becomes smaller than the load power will be described. It is assumed that a plurality of controllable power generation facilities exist in the system A, and the power quality of the system A is maintained by the supply and demand control of the host controller 10.

  When the power supplyable power on the system A side becomes smaller than the load power, a phenomenon such as a frequency drop in the system A occurs due to insufficient supply power. This situation is detected by an after-mentioned interconnection start condition detecting means provided in the host control device 10 or the operation control device 11, and the variable speed system on the system B side is connected to the system B.

An example of a connection start condition detection circuit which is a connection start condition detection means is shown in FIG. In FIG. 2, the interconnection start condition detection circuit 30 calculates the difference (P _G −P _L ) between the total generated power P _G that can be supplied by the grid A and the total load power P _L monitored by the host controller 10. The calculation unit 31 calculates and inputs the signal to the signal comparator 32. A determination value _PO is set in the signal comparator 32. Signal comparator 32 the difference between the generated power sum P _G and load power sum P _L that is input to the (P G _{-P L)} falls below the determination value P _O when the signal comparator 32 operates, its output on-delay timer 33. The on-delay timer 33 provides a time limit for preventing malfunction, operates the set side of the flip-flop 34, outputs Q, and combines the start interlock signal and the AND logic 35 to form the variable speed system start signal on the system B side. 36 is output. When this interconnection start condition detection circuit 30 is provided in the host control device 10, it is given to the variable speed system on the system B side via the operation control device 11. The generated power total P _G and the load power total P _L may be actual values or predicted values at that time.

  Since the variable speed generator-motor 3B rotates as described above, the main circuit breaker 1B and the excitation circuit breaker 6B are closed to activate the secondary exciter 5B, and a voltage is generated in the stator of the variable-speed generator motor 3B. Let The excitation frequency corresponding to the slip frequency between system B and the rotor speed is set to the frequency, and the voltage and phase are controlled to coincide with system B by d-axis control and q-axis control. If the device 4B is turned on, the connection to the system B is completed.

After the variable speed system on the system B side is connected to the system B, the variable speed system on the system B side uses the operation control device 11 to connect the q-axis signal selection unit 23B to keep the power on the accommodative side constant. A selection command for selecting the active power control unit 20B is given. The power command value Pg ^* is given a power value necessary for accommodation by taking into account the loss of the power accommodation device from the supply and demand control of the host controller 10. As a result, the power on the accommodating side can be controlled to be constant.

For the d-axis control, the host controller 10 or the operation controller 11 selects the voltage controller 22B or the reactive power controller 21B. In general, when connected to the system B, which is a large-scale system, the reactive power command value Qg ^* = 0 is set in order to prevent the variable speed system on the system B side from supplying or absorbing excessive reactive power. Reactive power control is selected.

  As described above, the power interchange apparatus according to the first embodiment always operates the variable speed system on the system A side as a phase adjusting facility that adjusts the voltage and reactive power of the system A, and the power supply of the system A is insufficient. By detecting this, the variable speed system on the system B side can be started, and power interchange can be performed from the system B side to the system A side.

  In the above description, the connection condition to the system B is described as an example of detecting the difference between the total generated power PG of the system A and the total load power PL (PG-PL). The detection may be based on fluctuations and fluctuations in the rotational speed of the variable speed generator-motor 3A. Further, by using a power electronics converter for the main circuit in the secondary excitation devices 5A and 5B, high-speed control is possible, and power interchange is possible with a short start-up time.

  Furthermore, although the case where the rotor position detection is performed by the sensors 14A and 14B has been described in the first embodiment, since the same rotation shaft 9 is used, only one sensor may be used. Further, in the above description, the connection start determination of the variable speed system on the system B side has been described by way of example using the connection start condition detection circuit 30 based on circuit logic. be able to.

  In the above description, the case where power is interchanged from the system B side to the system A side has been described, but the same applies to the case where power is interchanged from the system A side to the system B side.

Embodiment 2. FIG.
Next, a power interchange apparatus according to Embodiment 2 of the present invention will be described. In the first embodiment, when the variable speed system on the system A side is normally operated as a phase adjusting equipment for adjusting the voltage and reactive power of the system A, and the power that can be supplied by the system A becomes smaller than the load power, the system B In the second embodiment, power is exchanged from the side to the system A side. However, in the second embodiment, a switching period until the variable speed system on the system A side is connected to the variable speed system on the system B side, using rotational energy. It is intended to suppress the frequency drop of the grid A where power is insufficient.

  FIG. 3 is a diagram for explaining a power interchange apparatus according to the second embodiment. In FIG. 3, reference numerals 40A and 40B denote frequency detectors provided in the excitation control devices 15A and 15B, respectively. Other configurations are the same as those in FIG. 1, and the description thereof is omitted by giving the same reference numerals.

In the second embodiment, the excitation control device 15A is provided with the frequency detection unit 40A, and as shown in FIG. 4 as an example, the control unit of the frequency control unit 41a that performs frequency control when the frequency of the system A changes is the excitation device 15A. The logic unit is provided in the host control device 10 or the operation control device 11. Although the response is slightly delayed, all of 41a may be provided in the host control device 10 or the operation control device 11. That is, the frequency f of the system A is detected by the frequency detection unit 40A and is controlled by the frequency control unit 41a to correct the rotation speed command value N ^*. During the switching period until the power is connected to the power supply, the frequency reduction of the system A where power is insufficient is suppressed by using rotational energy. Accordingly, the frequency control unit 41a functions as a control unit that controls the release and absorption of the rotational energy of the variable speed generator-motors 3A and 3B. In FIG. 4, reference numeral 42 is a frequency deviation value acquisition unit, reference numeral 43 is a PID control function unit, reference numeral 44 is NOT logic, reference numeral 45 is AND logic, reference numeral 46 is a switch that operates based on the output of the AND logic 45, Reference numeral 47 denotes an adding unit, and reference numeral 48 denotes a corrected rotation speed command value N ^* .

That is, the frequency deviation in the PID control function unit 43 with respect to the rotational speed command value N ^* of the variable speed system on the system A side by the variable speed system activation signal 36 (see FIG. 2) on the system B side as shown in FIG. The deviation value (f ^* −f) between the reference frequency f ^* acquired by the value acquisition unit 42 and the frequency f of the system A is input to the PID control function unit 43, and this output signal is added by the addition unit 47 to obtain the rotational speed command value. Is reduced, and the rotational energy of the variable speed generator-motor 3A is released to supply power to the system A from the variable-speed generator motor 3A, thereby suppressing a decrease in frequency. Since the system B side also has a variable speed system configuration, it can be connected to the system A without any problem even if the rotation speed is changed by this control.

  As described above, according to the power accommodation device according to the second embodiment, the rotational energy of the variable speed generator-motor 3A is released, and the frequency fluctuation until the start of power accommodation is reduced. There is an effect to reduce the influence.

  In the above description, the case where power is interchanged from the system B side to the system A side has been described, but the same applies to the case where power is interchanged from the system A side to the system B side.

Embodiment 3 FIG.
Next, a power interchange apparatus according to Embodiment 3 of the present invention will be described. In the second embodiment, the rotational energy of the variable speed generator-motor 3A is released, and during the period from when the system A is connected to the system B to start power interchange, the variable speed system activation signal 36 on the system B side is used. Although the embodiment that suppresses the frequency drop of the system A has been described, the third embodiment describes a power accommodation device that can be operated as a power smoothing facility that uses the rotational energy of the variable speed generator-motor 3A.

  FIG. 5 is a diagram for explaining the power interchange apparatus according to the third embodiment. In FIG. 5, the code | symbol 41b has shown the frequency control part provided in 15 A of excitation control apparatuses. In this frequency control unit 41b, an AND logic 49 that receives the variable speed system stop signal and power smoothing control use signal on the system B side, and a variable speed system interconnection signal and power smoothing control use signal on the system B side are input. The AND logic 50, a first OR logic 51 that receives the connection start condition establishment signal and the output signal of the AND logic 50 as inputs, and a second that operates the switch 46 with the outputs of the AND logic 49 and the OR logic 51 as inputs. OR logic 54 is included. 55 is a limiter for limiting the upper limit value and the lower limit value of the output of the PID control function unit 43. If the AND logic 49 is established, the value 52 (allowable slip frequency-tolerance) becomes the LMT value, and the OR logic 51 If is established, the value 53 (allowable slip frequency) becomes the LMT value. Other configurations are the same as those in the second embodiment, and a description thereof will be omitted.

The output of the frequency control unit 41b configured as described above, that is, the output from the switch 46 and the rotational speed command value N ^* are added by the adding unit 47 to form a corrected rotational speed command value N ^* 48. .

In the power accommodation apparatus according to Embodiment 3, the frequency control unit 41b configured as described above can always correct the rotational speed command value N ^* within a range of ± (allowable slip frequency−tolerance), so that the rotational energy Is used as a power smoothing facility that utilizes the rotational energy of the variable speed generator-motor 3A. In addition, before the connection to the system B and in the connection state, the range is expanded more than usual, and the rotational speed command value N ^* can be corrected within a range of ± (allowable slip frequency). Therefore, even if the rotational speed of the variable speed generator-motor 3A is a limit value of (allowable slip frequency-tolerance) due to normal power smoothing, the energy is further increased to (allowable slip frequency) before and in the connected state. Can be used to smooth the power. Thus, the power smoothing of the system A can be realized, and the power quality of the system A is improved. Further, when connected to the system B, the power smoothing of the system B can be achieved by setting the variable speed system on the system B side to the same control.

Embodiment 4 FIG.
Next, a power interchange apparatus according to Embodiment 4 of the present invention will be described. In the third embodiment, the case where the rotational energy of the variable speed generator-motor 3A is used for the purpose of power smoothing has been described. However, the fourth embodiment is based on power fluctuations (acceleration and deceleration of the entire system) caused by a grid fault or the like. The power interchange apparatus that can be quickly converged will be described.

FIG. 6 is a diagram illustrating a power interchange apparatus according to the fourth embodiment. In FIG. 6, reference numeral 60 denotes a control phase unit, and this control phase unit 60 uses the frequency change of the system A in place of the PID control function unit 43 described in the second or third embodiment. , Gain, incomplete differentiation, and lead / lag function. Then, the signal via the control phase unit 60 is added to the rotational speed command value N ^* by the adding unit 47 and output to the rotational speed control unit 61 to change the q-axis current command value iq ^* and rotate at an appropriate timing. It is designed to release and absorb energy. That is, when the entire system is decelerating, the control phase unit 60 releases rotational energy to suppress deceleration, and when the entire system is accelerated, absorbs it as rotational energy and suppresses acceleration to release rotational energy. It functions as a suppression means for causing absorption. The frequency deviation value acquisition unit 42 and the control phase unit 60 constitute a frequency control unit 41c. Other configurations are the same as those in the second embodiment or the third embodiment, and a description thereof will be omitted.

  The power interchange apparatus according to the fourth embodiment includes the control phase unit 60 configured as described above, so that power fluctuations (acceleration and deceleration of the entire system) that occur due to a system fault or the like in the system A can be promptly performed. It can be converged and has the effect of improving the stability of the system. Note that this control is effective even when the variable speed system on the system B side is connected to the system B for power interchange. Further, when connected to the system B, it is possible to stabilize the system B by setting the variable speed system on the system B side to the same control. In the above description, the case where power is interchanged from the system B side to the system A side has been described, but the same applies to the case where power is interchanged from the system A side to the system B side.

Embodiment 5 FIG.
Next, a power interchange apparatus according to Embodiment 5 of the present invention will be described. In the first to fourth embodiments, the case where the small-scale network is the system A and the large-scale system is the system B and power is exchanged from the system B side to the system A side is described. A power interchange apparatus that enables bidirectional power interchange will be described.

FIG. 7 is a diagram for explaining a power interchange apparatus according to the fifth embodiment. In FIG. 7, reference numeral 65 denotes a control selection function unit. When the control selection function unit 65 is provided in the operation control device 11, when the system B requires power, the same applies to a request from the system B. Power can be accommodated by startup and interconnection control. That is, the AND logic 66 outputs the power control selection signal 67 to the variable speed system on the system A side according to the AND condition of the interchange request signal from the system B side and the parallel completion signal to the system B, and The rotational speed control selection signal 68 is output to the variable speed system. That is, the direction in which power is interchanged changes, and the variable speed system on the system A side becomes the side where the variable speed system is accommodated, and the variable speed system on the system B side becomes the side on which the accommodation is accommodated. Thus, the power control can be selected as the q-axis control of the variable speed system on the system A side, and the rotation speed control can be selected as the q-axis control of the variable speed system on the system B side, and the power on the power interchange side can be made constant. Other configurations are the same as those in Embodiments 1 to 4, and the description thereof is omitted.

  The power accommodation apparatus according to the fifth embodiment includes the control selection function unit 65 configured as described above. When the control selection function unit 65 switches the control mode of the variable speed generator motors 3A and 3B, When the power system has a certain amount of power supply margin during normal times, it is effective when emergency accommodation becomes necessary due to an accident or the like. Note that the reverse is selected when operation with constant power control on the receiving side is allowed.

Embodiment 6 FIG.
Next, a power interchange apparatus according to Embodiment 6 of the present invention will be described. In the first to fifth embodiments, the embodiment in which only the rotor is mechanically connected to the rotating shaft 9 of the two variable speed generator-motors 3A and 3B has been described. A power accommodation apparatus will be described in which a flywheel is provided on the rotating shaft 9 to increase the rotational energy that can be accumulated in the rotating body.

  FIG. 8 is a diagram for explaining a power interchange apparatus according to the sixth embodiment. In FIG. 8, reference numeral 70 denotes a flywheel provided on the rotary shaft 9. Other configurations are the same as those of the first to fifth embodiments, and the description thereof is omitted.

  Since the power accommodation apparatus according to the sixth embodiment is provided with the flywheel 70 having a large inertia on the rotating shaft 9 as described above, the rotational energy that can be accumulated in the rotating body can be increased, and the power fluctuation of the system can be further increased. In contrast, the rotational energy can be absorbed and released, and the power smoothing ability and the power system stabilization ability are improved.

Embodiment 7 FIG.
Next, a power interchange apparatus according to Embodiment 7 of the present invention will be described. In the first to sixth embodiments, the case where the two variable speed generator-motors 3A and 3B are configured to rotate on the same rotating shaft 9 has been described. In the seventh embodiment, the variable speed system on the system A side is configured. A synchronous machine system consisting of a synchronous machine, an excitation device, and an excitation transformer, which is always operated as a phase adjuster for adjusting voltage and reactive power, and a variable-speed system on the system B side when power interchange is required A power accommodation apparatus that is connected to B and performs power accommodation will be described.

  FIG. 9 is a diagram for explaining a power interchange apparatus according to the seventh embodiment. In FIG. 9, reference numeral 75 denotes a synchronous machine, reference numeral 76 denotes an excitation device for the synchronous machine 75, and reference numeral 77 denotes an excitation transformer. The synchronous machine system is configured by the synchronous machine 75, the excitation device 76, and the excitation transformer 77. It is composed. Other configurations are the same as those of the first embodiment or the second to sixth embodiments, and the description thereof is omitted by giving the same reference numerals.

Even if the system A side is the synchronous machine 75 as in the seventh embodiment, the apparatus activation from the stop time can be activated by the following procedure and the synchronous machine 75 can be inserted into the system A. That is,
(1) At the time of startup, the power source of the variable speed system on the system B side is switched to the system A, and the rotational speed is increased in the same manner as the system A side variable speed system startup method described in the first embodiment.
(2) As with normal power generation equipment, the speed (frequency) of the synchronous machine 75 is adjusted by the variable speed system on the system B side, and the voltage of the synchronous machine 75 is adjusted by the excitation device 76 of the synchronous machine 75. Synchronize with system A and enter system A.
(3) The power source of the variable speed system on the system B side is disconnected from the system A, the excitation of the variable speed system on the system B side is stopped, and only the variable speed generator motor 3B is rotating.
(4) After that, it is always operated as a synchronous phase adjuster, and when power accommodation is necessary, power accommodation can be performed in the same manner as in the first embodiment.
In the power interchange apparatus according to the seventh embodiment, the variable speed system on the system A side is a synchronous machine system including the synchronous machine 75, the excitation device 76, and the excitation transformer 77 as described above. A power interchange device can be obtained. The synchronous machine 75 has the same effect regardless of whether it is a thyristor excitation system or a brushless excitation system.

  In the seventh embodiment, the variable speed system on the system A side is a synchronous machine system including a synchronous machine 75, an excitation device 76, and an excitation transformer 77, and is always operated as a phase adjuster for adjusting voltage and reactive power. In the case where power interchange is necessary, the system for connecting the variable speed system on the system B side to the system B to perform power interchange has been described. However, the system A and the system B are reversed, and the system B side variable speed system is used. Is a synchronous machine system consisting of a synchronous machine, exciter, and exciting transformer, and is always operated as a phase adjuster for adjusting the voltage and reactive power. When power interchange is required, a variable speed system on the system A side is used. A method of connecting to the grid A and performing power interchange may be adopted.

Embodiment 8 FIG.
Next, a power interchange apparatus according to Embodiment 8 of the present invention will be described. In the first to seventh embodiments, the case of performing power constant control on the power interchange side at the time of power interchange has been described. However, in the case of the secondary excitation method, the secondary excitation device capacity corresponding to the allowable slip frequency may be used. It is more economical than the excitation method. However, if power smoothing control or power system stabilization control is performed on the side receiving the accommodation, if the amount of change increases, the rotational speed changes greatly, exceeding the variable speed width that is the allowable slip frequency width.

  In this case, the variable speed deviation deviation control that is normally added to the excitation control devices 15A and 15B of the variable speed system operates, and the slip frequency is maintained at the variable speed width limit value. This limiting operation can be realized by making the power of the accommodating side and the receiving side the same so that the slip does not change, but the power from the system B which is a large power system to the system A which is a small power system network In the case of accommodation, the power on the system B side having little influence even if the power is changed is changed.

In other words, the power command value P ^* that is controlled so that the accommodation power is constant is changed, which means that the accommodation power constant control cannot be maintained. Normally, the supply / demand control on the system A side returns to the original interchangeable power from this state, but the interchangeable power remains changed during this period. In the eighth embodiment, a power interchange apparatus that can correct the power command value Pg ^* and keep the power amount for a predetermined time even when the instantaneous power cannot be kept constant in this way will be described. is there.

FIG. 10 is a diagram for explaining a power interchange apparatus according to the eighth embodiment. In FIG. 10, reference numeral 80 denotes a power command value correction unit, reference numeral 81 denotes a first electric energy calculation unit, reference numeral 82 denotes a second electric energy calculation unit, reference numeral 83 denotes an electric energy deviation value acquisition unit, and reference numeral 84 denotes an electric power deviation value acquisition unit. The PI function part is shown. The first power amount calculation unit 81 calculates the power amount when the power to be maintained constant is accommodated for a predetermined time, and the second power amount calculation unit 82 calculates the actual integrated power amount. . The power command value correction unit 80 is provided in the excitation control device 15B. Reference numeral 85 denotes an adding section between the power command value Pg ^* and the output of the PI function section 84, and reference numeral 86 denotes a signal after correcting the power command value.
Other configurations are the same as those in Embodiments 1 to 7, and the description thereof is omitted.

As described above, the power accommodation apparatus according to the eighth embodiment obtains the power command value Pg ^{* based} on the deviation between the electric energy when the electric power to be maintained constant is accommodated for a predetermined time and the actual accumulated electric energy. Since the correction is performed, the amount of power for a predetermined time can be made constant. As a result, even in a variable speed system having a restriction on the allowable slip range, there is an effect that the electric energy for a predetermined time can be kept constant. In the above description, the case where power is interchanged from the system B side to the system A side has been described, but the same applies to the case where power is interchanged from the system A side to the system B side.

Embodiment 9 FIG.
Next, a power interchange apparatus according to Embodiment 9 of the present invention will be described. In the eighth embodiment, the method of correcting the power command value Pg ^* with the amount of power for a predetermined time as the control when the instantaneous power cannot be maintained constant has been described. Control that makes the power command value Pg ^* constant for a predetermined time by comparing the average power value for a certain time with the power command value Pg ^* and controlling the average power value to be the power command value Pg ^*. Is realized.

FIG. 11 is a diagram illustrating a power interchange apparatus according to the ninth embodiment. In FIG. 11, reference numeral 90 indicates an actual power value averaging unit, reference numeral 91 indicates an active power control unit, and reference numeral 92 indicates a power control value. The actual power value averaging unit 90 calculates an average (moving average, etc.) of the actual power value for a certain time, and the active power control unit 91 calculates the average power value and power averaged by the actual power value averaging unit 90. The command value Pg ^* is compared with the comparison unit 93, and PID control is performed with the PID control function unit 94 to obtain a power control value 92. Other configurations are the same as those in the eighth embodiment, and a description thereof will be omitted.

As described above, the power accommodation apparatus according to the ninth embodiment has a function of calculating the average (moving average, etc.) of the actual power value over a certain period of time, and compares this average power value with the power command value Pg ^*. Thus, since the average power value is controlled to be the power command value Pg ^* , it is possible to realize the control in which the power command value Pg ^* is constant for the interchanged power for a predetermined time. In addition, although the system directly controlling by the deviation between the average power value and the power command value Pg ^* has been described above, the same effect can be obtained by a method of correcting the power command value Pg ^* by the average power value. Further, the same effect can be obtained even when the eighth embodiment and the ninth embodiment are used together. In the above description, the case where power is interchanged from the system B side to the system A side has been described, but the same applies to the case where power is interchanged from the system A side to the system B side.

Embodiment 10 FIG.
Next, a power interchange apparatus according to Embodiment 10 of the present invention will be described. In the first to ninth embodiments, a synchronous machine or a variable speed system on the system A side is normally connected to the system A, and power smoothing operation utilizing phase adjustment and rotational energy is performed, so that the system can be used when power is insufficient. It explained as connecting A and system | strain B and carrying out electric power interchange. In the tenth embodiment, each is always connected to a different system, and when both the system A side and the system B side are variable speed systems, the system B performs phase adjustment and power command value 0 kW operation, and the system A performs phase adjustment. And power smoothing operation that utilizes rotational energy or power system stabilization control, and when power accommodation becomes necessary, a power accommodation device that performs power accommodation by selecting an appropriate control and giving a command value depending on the accommodation direction Is described.

12 (a) and 12 (b) are diagrams for explaining the power interchange apparatus according to the tenth embodiment. FIG. 12 (a) shows a case where both the system A side and the system B side are variable speed systems. (B) is the logic in the case of a synchronous machine and a variable speed system. In FIG. 12A, reference numeral 95 denotes a first AND logic, which inputs a power accommodation operation signal and a power accommodation signal from the system A side to the system B side, and controls power on the system A side according to the AND condition. The selection power, the rotation speed control selection signal on the system B side, and the accommodation power command value Pga are output to the A side excitation control device 15A. Reference numeral 96 denotes a second AND logic, which outputs the accommodation power value Pgb according to the AND condition of the electricity accommodation operation signal and the electricity accommodation signal from the system B side to the system A side. Reference numeral 97 denotes an OR logic, which outputs a rotational speed control selection signal on the system A side or a power control signal on the system B side according to an OR condition between the power interchange operation no signal and the output of the second AND logic 96. .
FIG. 12B is a circuit similar to FIG. 12A, but since the system A side is a synchronous machine system using a synchronous machine from the variable speed system, the variable speed system on the system B side is always in the power control mode. . Further, with regard to the accommodation power value Pgb, the power accommodation command value Pgb having a negative polarity is provided for power accommodation from the system A side to the system B side, and the electricity accommodation command value Pgb having a positive polarity is represented by B Output to the side excitation device 15B. 12 is provided in the operation control device 11 or the host control device 10.

  As described above, the power accommodation apparatus according to the tenth embodiment always connects the variable speed system on the system A side and the variable speed system on the system B side to different systems. When command value 0 kw operation, power smoothing operation using power adjustment and phase stabilization in system A or power system stabilization control is required, and power interchange is required, select appropriate control and command value depending on the interchange direction. Can be given. Normally, the interconnection point for power interchange is near the ends of both power systems, and phase adjustment equipment is installed to maintain the voltage, but the above operation eliminates the need for other phase adjustment equipment. In addition to the economic effect, there is an effect of increasing the operation rate of the apparatus.

  As mentioned above, although the embodiment of the power interchange apparatus according to the present invention has been described, the present invention can be freely combined with each other within the scope of the present invention, and each embodiment can be appropriately modified or omitted. It is possible. In addition, the power accommodation apparatus according to the present invention can accommodate power not only between systems of the same frequency but also between systems of different frequencies such as 50 Hz to 60 Hz, 60 Hz to 50 Hz, etc. Power smoothing and power system stabilization control are possible as well as constant power control. By increasing the equipment capacity, it can be applied to private power generation equipment networks and large-scale power systems, or power interchange between large-scale power systems. .

A small network, B large system, 1A, 1B main circuit breaker, 2A, 2B step-up transformer, 3A, 3B variable speed generator motor, 4A, 4B synchronous circuit breaker, 5A, 5B secondary exciter, 6A, 6B Excitation breaker, 7A, 7B Secondary excitation transformer, 8A, 8B Startup stator short circuit switch, 9 rotary shaft, 10 host controller, 11 operation controller, 12A, 12B Voltage detection transformer, 13A, 13B Current detection transformer, 14A, 14B sensor, 15A, 15B excitation controller, 16A, 16B active power detector, 17A, 17B reactive power detector, 18A, 18B voltage detector, 19A, 19B Rotational speed control unit, 20A, 20B active power control unit, 21A, 21B reactive power control unit, 22A, 22B voltage control unit, 23A, 23B q-axis signal selection unit, 24A, 2 B d-axis signal selection unit, 25A, 25B rotation speed detector, 30 linkage start condition detection circuit, 31 calculation unit, 32 signal comparator, 33 on-delay timer, 34 flip-flop, 35, 45, 49, 50, 66 AND logic, 36 variable speed system activation signal, 40A, 40B frequency detection unit, 41a, 41b, 41c frequency control unit, 42 frequency deviation value acquisition unit, 43 PID control function unit, 44 NOT logic, 46 switch, 47, 85 addition , 48 Rotational speed command signal after correction, 51 First OR logic, 52 First LMT signal, 53 Second LMT signal, 54 Second OR logic, 55 Limiter, 60 Control phase section, 61 Rotational speed Control unit, 65 Control selection function unit, 67 Power control selection signal, 68 Speed control selection signal, 70 75, 102 synchronous machine, 76 excitation device, 77 excitation transformer, 80 power command value correction unit, 81 first power amount calculation unit, 82 second power amount calculation unit, 83 power amount deviation value acquisition Part, 84 PI function part, 86 power command value corrected signal, 90 actual power value averaging part, 91 active power control part, 92 power control value, 93 comparison part, 94 PID control function part, 100A, 100B three-phase main Transformer, 101A, 101B cycloconverter, 103A, 103B three-phase high-frequency voltage, 104A, 104B single-phase AC voltage.

Claims (10)

A first rotating machine connected to the first power system and operating as an electric motor and a generator;
A second rotating machine that rotates on the same rotating shaft as the first rotating machine and that is connected to the second power system and operates as an electric motor and a generator;
A control device for operating the first and second rotating machines as a variable speed machine;
With
Normally, the first rotating machine is connected to the first power system, the second rotating machine is disconnected from the second power system, and the first rotating machine is connected to the first power system. It operates as a phase adjusting means for adjusting voltage and reactive power, and the second rotating machine is connected to the second power system according to the supply and demand situation of the first power system, and the first power system and the above A power interchange apparatus characterized in that power is exchanged between second power systems.   Control means for controlling the release and absorption of the rotation energy of the first and second rotating machines is provided, and the rotation and release of the rotation energy is performed by the control means until the transfer of the electric power is started. The power interchange apparatus according to claim 1, wherein frequency fluctuation is suppressed.   Limiting means for limiting the range of use of the rotational energy is provided, and control for smoothing the difference in the supply and demand power of the first power system by always limiting the range of use of the rotational energy is performed, and the second power system The power interchange apparatus according to claim 2, wherein after starting the connection control to the power, control is performed to suppress frequency fluctuation by using the rotational energy to the limit. Comprising suppression means for releasing and absorbing rotational energy of the first and second rotating machines at a timing at which power fluctuation can be suppressed;
When the first power system and the second power system are separated, the power interchange device connected to the first power system
When the first power system and the second power system are connected, a power accommodation device connected to the first power system and a power accommodation device connected to the second power system. The power interchange apparatus according to any one of claims 1 to 3, wherein the power fluctuation is suppressed by either one or both.   A control selection function unit that switches a control mode of the first and second rotating machines at the start of the transmission / reception of the electric power, and the transmission / reception of the electric power according to a request from the second electric power system. The power interchange apparatus according to any one of 1 to 4.   The power accommodation apparatus according to any one of claims 1 to 5, wherein a flywheel is provided on the rotating shaft to increase rotational energy that can be stored in the first and second rotating machines.   The power interchange according to any one of claims 1 to 6, further comprising a control device that controls one of the first and second rotating machines in place of the synchronous machine and controls the synchronous machine. apparatus.   8. A device according to claim 1, further comprising means for correcting a power command value based on a deviation between a power amount when the power to be maintained constant is accommodated for a predetermined time and an actual accumulated power amount. A power interchange apparatus according to claim 1.   The power interchange apparatus according to any one of claims 1 to 7, further comprising means for calculating an average value of actual power for a certain period of time and controlling the average value to be constant. The power interchange apparatus according to any one of claims 1 to 9, further comprising means for connecting the first and second rotating machines to different power systems.

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