JPH1141820A - Single operation detector for distributed power supply - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve operation reliability of a distributed power supply in a system interconnection state, by a method wherein a periodical minute fluctuation is given to the active set power device of the automatic power regulator of the distributed power supply, and an active power at a receiving point is periodically changed to break balance actively to detect a single operation. SOLUTION: A fluctuation signal generating circuit 51 which gives a periodical minute fluctuation to the active set power device of an active power regulator 21c is provided in a single operation detector 50 for a synchronous generator 21. If a commercial system 10 is cut off, the synchronous generator 21 is put into a single operation. In this state, the frequency of the output of the synchronous generator 21 is increased in a (+) polarity and decreased in a (-) polarity in accordance with the periodical minute fluctuation. The longer the duration time of the single operation, the larger the fluctuation width of the frequency. If the fluctuation width exceeds a lower limit value, it is detected by a single operation signal generating circuit 52 which generates a single operation signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distributed power supply system in which a distributed power supply is connected to an electric power system to detect that the distributed power supply is disconnected from the power system during system interconnection and becomes an isolated operation. The present invention relates to an isolated operation detection device for a power supply.

[0002]

2. Description of the Related Art Conventionally, this type of isolated operation detection device has detected an isolated operation of a distributed power supply by using a method of interrupting a transfer or a method of monitoring voltage or frequency. These methods will be described with reference to FIG. FIG.
FIG. 1 is a block diagram showing a configuration of a conventional islanding detection device.

[0005] In FIG. 5, reference numeral 10 denotes a commercial system side, and an infinite bus 11 and a transmission line 12 of the commercial system side 10 are connected to a customer side 20 via a system breaker 13. A synchronous generator 21 as a distributed power source on the customer side 20 is connected to the commercial system side 10 via a synchronous generator breaker 22 and a detector-side circuit breaker 23, and is connected to the power system to operate. The on-site load 30 on the customer side 20 is connected to the commercial system side 10 via the on-site load circuit breaker 31 and the detector-side circuit breaker 23, and via the on-site load circuit breaker 31 and the synchronous generator circuit breaker 22. It is also connected to the synchronous generator 21. Further, the external load 32 on the consumer side 20 is connected to the commercial system side 10 via an external load side circuit breaker 33, and the synchronous generator is connected via the detector side circuit breaker 23 and the synchronous generator circuit breaker 22. 21.

In the apparatus for detecting the independent operation of the synchronous generator 21 of the consumer side 20 connected to the commercial system side 10 and operating in parallel with the electric power system as described above, the detection of the isolated operation by the transfer cutoff system is performed by the commercial system. System breaker 1 on system side 10
3 is shut off, and the synchronous generator 21 on the consumer side 20 is disconnected from the commercial system side to enter the isolated operation state.
This is a method of interrupting the transfer of the detector-side circuit breaker 23 and the external load-side circuit breaker 33 of the customer side 20 by the transfer interruption signal 14 from 0.

In the method of monitoring voltage and frequency,
As shown in FIG. 5, the voltage and frequency detected by the voltage detector 40 and the frequency detector 41 connected to the system on the customer side 20 are input to the isolated operation detection circuit 42. That is, the method of monitoring the voltage and the frequency is based on the isolated operation detection circuit 4.
2 is a method of monitoring changes in the voltage and frequency of the system on the customer side 20 and passively detecting islanding.

[0006]

However, in the above-mentioned conventional islanding operation detecting apparatus, the method of detecting the islanding operation by the transfer interruption method requires the use of a dedicated line for transmitting the transmission interruption signal 14, and the future When the number of distributed power supplies increases, there is a disadvantage that the capacity of the dedicated line needs to be increased. Also, the transfer cutoff signal 14
The use of line sharing and wireless transmission for transmission is not realistic and economically problematic.

Further, in the method of detecting the islanding operation by monitoring the voltage and the frequency, the capacity of the load (the external load 32 and the in-house load 30) on the customer side 20 and the synchronous generator 21
Power regulator 21 for controlling a motor 21a for driving the motor
The synchronous generator 21 based on the set value of the active power setting device of b
Therefore, there is a problem that it is impossible to detect when there is no power flow between the commercial system side 10 and the customer side 20 because the power generation amount is balanced.

An object of the present invention is to provide an isolated operation detection device for a distributed power supply that solves the above problems.

[0009]

According to a first aspect of the present invention, there is provided an islanding operation detecting apparatus for detecting that a distributed power source is disconnected and becomes an isolated operation during interconnection between a power system and a distributed power source.
An active power adjusting device for adjusting the active power output from the distributed power supply, a fluctuation signal generating circuit for periodically giving a minute change to the active power setting device of the active power adjusting device, and a receiving point or a frequency of the distributed power supply is detected. Frequency detector, and when the fluctuation signal generating circuit constantly gives a minute change to the active power output from the distributed power supply, and when the deviation between the output of the frequency detector and a predetermined reference frequency is equal to or more than a certain value. And an isolated operation signal generation circuit for generating an isolated operation signal.

According to a second aspect of the present invention, there is provided an islanding operation detecting device for detecting that a distributed power source is disconnected and becomes an isolated operation during interconnection between a power system and a distributed power source, and the distributed power source outputs the signal. An active power adjusting device for adjusting the active power, a fluctuation signal generating circuit that gives a small periodic change to the active power setting device of the active power adjusting device, and a frequency detector for detecting a frequency of a receiving point or a distributed power supply, An amplifier circuit for monitoring a minute change in the output of the frequency detector, and amplifying the amplitude of the output of the change signal generating circuit for a predetermined minute time when the output value deviates from a predetermined upper limit or lower limit. When the active power output from the distributed power supply is constantly minutely changed by the amplification circuit and the fluctuation signal generating circuit, when the deviation between the output of the frequency detector and a predetermined reference frequency is equal to or more than a predetermined value. Isolated operation And a single driving signal generating circuit for generating a degree.

According to a third aspect of the present invention, there is provided an islanding operation detecting device for detecting that a distributed power source is disconnected and becomes an isolated operation during interconnection between a power system and a distributed power source, and the distributed power source outputs the signal. An active power adjusting device for adjusting the active power, a fluctuation signal generating circuit that gives a small periodic change to the active power setting device of the active power adjusting device, and a frequency detector for detecting a frequency of a receiving point or a distributed power supply, A minute fluctuation in the output of the frequency detector is monitored, a timer is started when the output value deviates from a predetermined upper limit or a lower limit, and when the timer elapses a predetermined time, the fluctuation signal is generated. A delay amplifying circuit for amplifying the amplitude of the output of the circuit for a predetermined very short time; and a delay amplifier for constantly giving a minute change to the active power output from the distributed power supply by the delay amplifying circuit and the fluctuation signal generating circuit. Output And a single driving signal generating circuit for generating a single operation signal when the deviation between the predetermined reference frequency is a certain value or more.

According to a fourth aspect of the present invention, in any one of the first to third aspects, the distributed power supply comprises a synchronous generator. In a fifth aspect based on any one of the first to third aspects, the distributed power source comprises an induction generator and a phase adjusting facility. According to the invention,
Change the active power output from the distributed power supply periodically by applying a small periodic change to the active power setting device of the distributed power supply during the grid connection, and change the power receiving point or the frequency of the distributed power supply. , The isolated operation of these distributed power sources can be detected. That is, the islanding operation detection apparatus for a distributed power supply according to the present invention detects the islanding operation by actively breaking the equilibrium state by giving a periodic minute fluctuation to the active power output of the distributed power supply.

[0013]

FIG. 1 is a block diagram showing an isolated operation detection apparatus for a synchronous generator as a distributed power supply according to a first embodiment of the present invention. The conventional isolated operation shown in FIG. Components having the same functions as those in the block diagram showing the configuration of the detection device are denoted by the same reference numerals, and detailed description thereof will be omitted.

That is, in FIG. 1, the isolated operation detecting device 50 of the synchronous generator 21 includes a fluctuation signal generating circuit 51 for periodically giving a minute fluctuation to the active power setter of the active power regulator 21c; The output of the frequency detector 41 connected to the system is monitored, and this output is used as the reference frequency (f ₀ ).
And an isolated operation signal generating circuit 52 composed of a comparator, an OR element, and the like for detecting that the frequency deviates from the allowable upper and lower limit values (f ₀ ± Δf ₁ Hz) of 50 Hz or 60 Hz.

The operation of the islanding detection device 50 shown in FIG. 1 will be described below. The power generation amount of the synchronous generator 21 based on the setting value of the active power setter of the automatic power regulator 21b that controls the prime mover 21a that drives the synchronous generator 21 during the interconnection operation in the normal state, and the load 30 and External load 32
In the state where the power consumption is balanced with the amount of power consumed, the periodic minute fluctuation from the fluctuation signal generating circuit 51 is added to this set value. A slight tidal current is generated based on the minute fluctuation. In this state, the output of the frequency detector 41 has the same value as that of the commercial system side 10, and is a value substantially corresponding to the reference frequency (f ₀ ).

Here, in the event of a commercial system accident 10 or the like,
When the commercial system side 10 is disconnected by the circuit breaker 13,
Period generator 21 is in an independent operation state. In this state
Is the output of the synchronous generator 21 based on the periodic minute fluctuation.
The frequency of the force rises when the minute fluctuation is the (+) polarity,
The small fluctuation falls for the (-) polarity, and the fluctuation width of this frequency is
It increases as the duration of the islanding operation increases,
The upper and lower limits (f ₀± Δf₁Hertz)
And the isolated operation signal generation circuit 52 detects this, and
Generate a reverse signal.

FIG. 2 is a block diagram showing a second embodiment of the present invention.
A block diagram of an isolated operation detection device for a synchronous generator as a distributed power source.
FIG. 2 is a block diagram showing a configuration of the isolated operation detection device 50 shown in FIG.
Blocks with the same functions as those in the block diagram
One reference numeral is attached and the detailed description is omitted. Ie
In FIG. 2, the isolated operation detecting device 60 of the synchronous generator 21 is shown.
Includes a frequency detector 41, a fluctuation signal generation circuit 51,
Monitor the output of the inverted signal generation circuit 52 and the frequency detector 41
This output is a predetermined upper and lower limit value (f₀± Δf_TwoHell
Tsu, Δf ₁> Δf_Two) Deviates when the fluctuation signal occurs
A comparator, an OR element, which increases the amplitude of the output of the
And an amplifier circuit 61 including a width unit and the like.

The amplifying circuit 61 of the islanding operation detecting device 60 shown in FIG. 2 makes it possible to detect the above-mentioned islanding operation more quickly. FIG. 3 is a block diagram of an isolated operation detection device for a synchronous generator as a distributed power supply according to a third embodiment of the present invention, and is a block diagram showing a configuration of the isolated operation detection device 50 shown in FIG. Those having the same functions as those described above are denoted by the same reference numerals, and detailed description thereof will be omitted.

That is, in FIG.
The islanding detection device 70 has a frequency detector 41, a fluctuation signal
Generating circuit 51, an isolated operation signal generating circuit 52,
The output of the output unit 41 is monitored, and this output is set to the upper and lower
(F₀± Δf_TwoHertz, Δf ₁> Δf_Two)
A timer is started when the timer has reached a predetermined time (T₀)
Increases, the amplitude of the output of the fluctuation signal generation circuit 51 increases.
It consists of a comparator, an OR element, a timer, an amplifier, etc.
And a delay amplifier circuit 71 formed.

The delay amplification circuit 71 of the islanding operation detecting device 70 shown in FIG. 3 prevents the above-described malfunction of the islanding operation detection and makes it possible to quickly detect the islanding operation. FIG. 4 is a block diagram showing an isolated operation detection device for an induction generator as a distributed power source according to a fourth embodiment of the present invention.
Those having the same functions as those in the block diagram showing the configuration of the islanding operation detection device 70 shown in FIG.

That is, in FIG. 4, the distributed power source is an induction generator 24, a motor 24a for driving the induction generator 24, and an automatic power regulator 24b for controlling the motor 24a to adjust the active power output from the induction generator 24. Is composed of
It is connected to the commercial system side 10 via the induction generator circuit breaker 25 and the detection device side circuit breaker 23, and is connected to the power system. In addition, a phase adjusting device 26 such as a power capacitor is connected to a system on the customer side 20 via a phase adjusting device circuit breaker 27 to improve the power factor of this system and the stability of the induction generator 24 during operation. It is being used for

The isolated operation detecting device 80 shown in FIG. 4 includes a frequency detector 41, a fluctuation signal generating circuit 51 for periodically giving a minute fluctuation to the active power setting device of the automatic power regulator 24b, an isolated operation signal generating circuit 52, The isolated operation detection device 80 includes a frequency detector 41 and a delay amplification circuit 71.
This is the same as the islanding operation detection device 70 shown in FIG.

[0023]

According to the present invention, the active setter of the automatic power regulator of the distributed power source in the grid connection is periodically subjected to minute fluctuations, and the active power at the receiving point is periodically changed to thereby enable active power control. The operation reliability can be increased because the state of equilibrium is disrupted and the islanding operation is detected, and transmission equipment such as a dedicated line for a cutoff signal which is necessary in the conventional transfer cutoff method is unnecessary, In addition, even in a state where there is no power flow due to a balance between the load capacity and the power generation amount of the distributed power supply, which is impossible with the conventional voltage and frequency monitoring methods, the isolated operation of the distributed power supply can be reliably detected.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an isolated operation detection device for a distributed power supply according to a first embodiment of the present invention;

FIG. 2 is a configuration diagram of an isolated operation detection device for a distributed power supply according to a second embodiment of the present invention;

FIG. 3 is a configuration diagram of an isolated operation detection device for a distributed power supply according to a third embodiment of the present invention;

FIG. 4 is a configuration diagram of an isolated operation detection device of a distributed power supply according to a fourth embodiment of the present invention;

FIG. 5 is a configuration diagram of an isolated operation detection device of a distributed power supply showing a conventional example.

[Explanation of symbols]

10 ... commercial system side, 11 ... infinite bus, 12 ... transmission line,
13: system circuit breaker, 14: transfer cutoff signal, 20: customer side, 21: synchronous generator, 21a: prime mover, 21b: automatic power regulator, 22: synchronous generator circuit breaker, 23: detection device side circuit breaker , 24 ... induction generator, 24a ... motor, 24b
... Automatic power conditioner, 25 ... Induction generator breaker, 26 ... Phase adjustment equipment, 27 ... Phase adjustment equipment breaker, 30 ... In-house load, 31
... in-house load breaker, 32 ... external load, 33 ... external load breaker, 40 ... voltage detector, 41 ... frequency detector, 42 ...
Islanding detection circuit, 50, 60, 70, 80 ... islanding detection device, 51 ... fluctuation signal generation circuit, 52 ... islanding signal generation circuit, 61 ... amplification circuit, 71 ... delay amplification circuit.

Claims (5)

[Claims] In an islanding operation detection device for detecting that a distributed power supply is disconnected and becomes an isolated operation during interconnection between a power system and a distributed power supply, an active power output from the distributed power supply is adjusted. An active power adjusting device; a fluctuation signal generating circuit for periodically giving a minute fluctuation to an active power setting device of the active power adjusting device; a frequency detector for detecting a power receiving point or a frequency of a distributed power supply; and the fluctuation signal generating circuit. An independent operation signal generation that constantly gives a minute change to the active power output from the distributed power supply and generates an isolated operation signal when a deviation between the output of the frequency detector and a predetermined reference frequency becomes a predetermined value or more. And a circuit for detecting an isolated operation of a distributed power supply. 2. An isolated operation detection device for detecting that a distributed power source is disconnected and becomes an isolated operation during interconnection between a power system and a distributed power source, wherein the active power output from the distributed power source is adjusted. An active power adjusting device, a fluctuation signal generating circuit for periodically giving a minute variation to an active power setting device of the active power adjusting device, a frequency detector for detecting a receiving point or a frequency of a distributed power supply, An amplifying circuit that monitors minute fluctuations in the output and amplifies the amplitude of the output of the fluctuation signal generating circuit for a predetermined short time when the output value deviates from a predetermined upper limit or lower limit; The fluctuation signal generating circuit constantly gives a minute change to the active power output from the distributed power supply, and outputs an isolated operation signal when a deviation between the output of the frequency detector and a predetermined reference frequency is equal to or more than a predetermined value. Occur Distributed power islanding detection apparatus characterized by comprising a German driving signal generating circuit. 3. An isolated operation detection device for detecting that a distributed power supply is disconnected and becomes an isolated operation during interconnection between a power system and a distributed power supply, wherein the active power output from the distributed power supply is adjusted. An active power adjusting device, a fluctuation signal generating circuit for periodically giving a minute variation to an active power setting device of the active power adjusting device, a frequency detector for detecting a receiving point or a frequency of a distributed power supply, Monitor a minute fluctuation of the output, start a timer when the output value deviates from a predetermined upper limit or lower limit, and when the timer has passed a predetermined time, the amplitude of the output of the fluctuation signal generating circuit And a delay amplifier circuit for amplifying the active power output from the distributed power supply by the delay amplifier circuit and the fluctuation signal generating circuit by the delay amplifier circuit and the fluctuating signal generating circuit. Reference circumference Independent operation detecting apparatus of the distributed power supply, wherein a deviation between the number and a single operation signal generation circuit for generating a single operation signal when a certain value or more. 4. The isolated operation detection apparatus for a distributed power supply according to claim 1, wherein said distributed power supply comprises a synchronous generator. apparatus. 5. An apparatus for detecting the isolated operation of a distributed power supply according to claim 1, wherein said distributed power supply comprises an induction generator and a phase adjusting facility. Power supply islanding detection device.