JP2005143231A - In-station independent operation shift controller and in-station independent operation shift control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To speedily decide the materialization of shift condition to FCB control for cutting a turbine generator unit linked to a transmission system off the transmission system due to the accident of the transmission system and switching it into in-station independent operation where the output of the generator is consumed in only the electric load within a power plant, in the thermal power plant. <P>SOLUTION: This controller is provided with a decision means 24 which computes the impedance of transmission lines 11a, 11b... from the voltage and the currents of the transmission lines 11a, 11b... and compares at least one of the computed rates of change or the absolute value of the impedance of the transmission lines 11a, 11b... with a reference value and outputs a signal in case that the value is over the reference value, and this outputs a signal of detection of shift to the in-station independent operation in case that the signal from the decision means 24 is entered and the signals from all decision means 24 are entered. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  In the thermal power plant, the turbine generator connected to the power transmission system is disconnected from the power transmission system due to a power transmission system accident or the like, and the output of the power generator is consumed only by the electric load in the power plant including the power generation equipment. The present invention relates to an in-house independent operation transition control device and an in-house independent operation transition control method for switching to in-house independent operation.

  Conventionally, as an in-house single operation transfer control device for a turbine generator in a thermal power plant, it was determined that an accident occurred in the transmission system to which the turbine generator was linked, and that power transmission from the power plant could not be continued. In this case, the turbine generator is temporarily disconnected from the power transmission system, and the transition control to low load operation is performed so that power can be supplied only to the in-house load of the thermal power plant by the disconnected turbine generator. It has an operation control function that waits for the accident recovery of the transmission system, and this function is controlled to shift to in-house single operation, or fast cutback control or fail cutback control (hereinafter abbreviated as FCB control). (For example, refer to Patent Document 1 or 2).

FIG. 2 is a system diagram showing a conventional thermal power plant and a power transmission system.
In FIG. 2, reference numeral 1 denotes a thermal power plant, in which high-temperature and high-pressure steam generated in a boiler 2 that is power generation equipment is sent to a steam turbine 4 through a steam control valve 3 to rotate the steam turbine 4.
Thereby, the turbine generator 5 directly connected to the steam turbine 4 is rotated, and the electric power generated by the turbine generator 5 is sent to the system bus 8 via the main transformer 6 and the circuit breaker 7.

The power sent to the system bus 8 is supplied to the power transmission system 11 composed of a plurality of power transmission lines 11a, 11b... Connected to the power transmission line breaker 9 and the opposite end circuit breaker 10 and sent to the substation 12.
The steam that has driven the steam turbine 4 returns to the boiler 2 again.

  Further, between the turbine generator 5 and the main transformer 6, an instrument transformer 13 for detecting the generator voltage and an instrument current transformer 14 for detecting the generator current are connected, and their outputs are It is input to the converter 15 and converted into an electric energy signal P. The electric energy signal P is input to the generator output detection device 16.

Further, the generator output detection device 16 is connected to a transition detector 18 of the in-house single operation transition control device 17.
Reference numeral 19 denotes an in-house load connected to the turbine generator.
Japanese Patent Laid-Open No. 3-251057 Japanese Patent Laid-Open No. 5-022867

  In such a thermal power plant, when the turbine generator 5 is operated and the generated power is sent to the power transmission system 11 via the main transformer 6 and the circuit breaker 7, an accident occurs in the power transmission system due to some abnormality. When power generation is not possible, the power plant side cuts off the circuit breaker 7 to disconnect the turbine generator 5 from the system bus 8 and narrows the output of the turbine generator 5 with the target of the on-site load 19 from the turbine generator 5. Power is supplied only to the in-house load 19 and the operation is shifted to FCB control for continuously operating the turbine generator 5 to wait for the accident recovery of the transmission system.

  Conventionally, the transition condition to this FCB control is that when all of the transmission line breakers 9 connected to the transmission lines 11a, 11b,... Have tripped, or that the detection output P of the turbine generator 5 has suddenly changed. The condition detected by the output detector 16 is used as a condition, whereby the transition control signal 20 is output from the transition detector 18 of the in-house single operation transition control device 17.

  Among these, in the condition of all trips of the transmission line breaker 9, even when all the transmission line breakers 9 do not trip, the transmission line in which the opposite end breaker 10 trips due to the combination with the opposite end breaker 10 is used. Since power cannot be transmitted to the substation 12, not only the trip condition of the transmission line breaker 9 on the outlet side of the power station but also the trip condition of the opposite-end breaker 10 is necessary.

  However, when the transmission line breaker 9 is a trip of all units, the condition for shifting to FCB control becomes complicated when the system side condition, particularly the breaker condition of the substation 12 on the opposite end side, is taken in, and the opposite end breaker 10 There is a problem that the cable of the restriction or the connection condition is necessary.

  Moreover, the frequency fluctuation of the turbine generator 5 generated as a secondary spillover due to a power transmission system failure and the load fluctuation accompanying the disconnection of the turbine generator 5 from the power transmission system 11 are detected and used as the transition condition to FCB control. Although a means is also considered, there is a problem that there is a time delay until the load fluctuation in the in-house single mode is detected, and it is not in time for the early determination time required by the in-house single operation transition control device 17 side.

  The present invention has been made to solve the above-described problems, has a simple configuration, and can be used to determine whether or not the transition condition to FCB control is established at high speed. The purpose is to provide.

  In order to achieve the above object, the invention according to claim 1 is provided in a power generation system including a generator connected via a power transmission system having a power transmission line, and shifts to in-house single operation at the time of a power transmission system failure. In the in-house single operation transition control device for controlling the power supply, an instrument transformer for detecting the voltage of the transmission line, an instrument current transformer for detecting the current of the transmission line, and the instrument transformer and the instrument current transformer The impedance calculation device that calculates the impedance of each transmission line from the detection signal, and the change rate of the transmission line impedance calculated by the impedance calculation device is compared with a reference change rate, and the change rate of the transmission line impedance is the reference Impedance change rate determination device that outputs a signal when the change rate exceeds, and signals from impedance change rate determination device are input, and all impedance change rates And having a transition detector for outputting a transition detection signal when the signal from the constant system has been entered.

  The invention according to claim 2 is provided in a power generation system including a generator interconnected via a power transmission system having a power transmission line, and controls a shift to a single operation in the station when a power transmission system fault occurs. In the apparatus, an instrument transformer for detecting the voltage of the transmission line, an instrument current transformer for detecting the current of the transmission line, and an impedance of each transmission line from the detection signal of the instrument transformer and the instrument current transformer When the absolute value of the impedance of the transmission line is compared with the reference absolute value and the absolute value of the impedance of the transmission line exceeds the reference absolute value The signals from the impedance absolute value determination device and the impedance change rate determination device that input signals are input, and the signals from all impedance absolute value determination devices are input. And having a transition detector for outputting a transition detection signal when the.

  According to a third aspect of the present invention, there is provided an in-house single operation shift control method in which a power generation system including a generator interconnected via a power transmission system having a transmission line is shifted to an in-house single operation in the event of a power transmission system failure. The impedance of each transmission line is calculated from the voltage and current, and if the calculated change rate or absolute value of the transmission line impedance exceeds the reference value for all of the transmission lines, A command for shifting to an isolated operation is output.

  According to the present invention, the determination circuit for shifting to the FCB operation can be simplified, and the circuit can be configured on the power plant side. Further, it is possible to shift to the FCB operation in a relatively early determination time required by the gas turbine.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description of the embodiment, the same parts as those in the conventional in-house single operation transition control device shown in FIG. 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 1 is a diagram showing a first embodiment of the present invention. In FIG. 1, reference numeral 21 denotes an instrument transformer for detecting the voltage of each of a plurality of power transmission lines 11a, 11b,. , 11b..., 11b..., 11b... Impedance calculation for calculating the impedance of the transmission lines 11a, 11b... By inputting the detection outputs of the instrument transformer 21 and the instrument current transformer 22. .., 24 is an impedance change rate determination device that outputs an output signal when the rate of change of the impedance values of the power transmission lines 11a, 11b... Input from the impedance arithmetic unit 23 exceeds the reference rate of change. The transition detector 25 of the in-house single operation transition control device to which the outputs of the plurality of impedance change rate determination devices 24 for each is input, is a turbine generator that is one or more in the power plant 1 A generator operation monitoring device for monitoring the operating condition of the machine 5.

Next, the operation of the first embodiment of the present invention will be described.
When the turbine generator 5 is operated and the generated electric power is sent to the power transmission system 11 via the main transformer 6 and the circuit breaker 7, it is detected by the instrument transformer 21 and the instrument current transformer 22. The voltage and current values of the transmission lines 11a, 11b,... Are sent to the impedance calculation device 23 for each line, and the impedance values for each transmission line are calculated.

  If an accident occurs in the power transmission system due to some abnormality during power transmission, and the power line breaker 9 and the opposite-end circuit breaker 10 all perform a cut-off operation, power transmission becomes impossible, and the impedance values of the power transmission lines 11a, 11b,. Suddenly changes.

  The impedance change rate determination device 24 compares the impedance change rate of the power transmission lines 11a, 11b... Input from the impedance calculation device 23 with the reference change rate, and the impedance change rate of the power transmission lines 11a, 11b. An output signal is output to the transition detector 18 when the rate of change is exceeded.

  At the same time, the generator generator monitoring apparatus 25 that monitors the operating state of one or a plurality of generators selects the target generator to be shifted to the in-house single operation, and the in-house single operation shift control device transition detector 18 is selected. Output to.

The transition detection unit 18 outputs a transition detection signal 20 when all impedance change rate determination devices 24 detect a sudden change state of the impedance value.
As a result, on the power plant side, the circuit breaker 7 of the target generator selected by the generator operation monitoring device 25 is turned off to disconnect the turbine generator 5 from the system bus 8, and turbine power generation is performed with the target generator targeted at the in-house load 19. The output of the machine 5 is reduced and power is supplied only to the in-house load 19 from the turbine generator 5, and the process shifts to FCB control for continuously operating the turbine generator 5 and waits for the accident recovery of the transmission system.

  According to the present embodiment, the impedance value is monitored for each line of the transmission line, and the rate of change of the impedance is set as the in-house single operation transition condition. It is not necessary to take in circuit breaker conditions such as an end circuit breaker, and the configuration is simple, and it is possible to quickly determine whether the condition for transition to FCB control is satisfied without time delay such as detection of frequency fluctuations and load fluctuations.

Next, a second embodiment of the present invention will be described.
In the second embodiment, as the in-house single operation transition condition, the impedance of each line is determined from the voltage and current values of the transmission lines 11a, 11b... Detected by the instrument transformer 21 and the instrument current transformer 22. The absolute value of the impedance for each power transmission line calculated by the calculation device 23 is detected, and when the absolute value exceeds the reference absolute value, the process shifts to FCB control.

For this reason, an impedance absolute value determination device (not shown) may be provided instead of the impedance change rate determination device 24 shown in the first embodiment shown in FIG.
Also in this embodiment, the same effect as in the first embodiment can be obtained.

  In addition to the FCB control, in the case where the in-house power is supplied from the system bus 8, the in-house power is supplied from the system bus 8, so that the system bus 8 is operated independently (LCB). In this case as well, the inventions shown in claims 1 to 3 can be applied.

The system diagram which shows the in-house independent operation transfer control apparatus and control method by the 1st Embodiment of this invention. The system diagram which shows the conventional in-house independent operation transfer control apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Thermal power plant, 2 ... Boiler, 3 ... Steam control valve, 4 ... Steam turbine, 5 ... Turbine generator, 6 ... Main transformer, 7 ... Circuit breaker, 8 ... System bus, 9 ... Transmission line breaker, DESCRIPTION OF SYMBOLS 10 ... Opposite end circuit breaker, 11 ... Power transmission system, 11a, 11b ... Transmission line, 12 ... Substation, 13 ... Instrument transformer, 14 ... Instrument current transformer, 15 ... Converter, 16 ... Generator output detection 17 ... In-house single operation transition control device, 18 ... Transition detection section, 19 ... In-house load, 20 ... Transition detection signal, 21 ... Transformer for instrument, 22 ... Current transformer for instrument, 23 ... Impedance calculation device, 24 ... impedance change rate determination device, 25 ... generator operation monitoring device.

Claims (3)

In the in-house single operation transition control device, which is provided in a power generation system composed of a generator interconnected via a power transmission system having a transmission line and controls the shift to in-house single operation at the time of a power transmission system fault,
An instrument transformer for detecting the voltage of the transmission line, an instrument current transformer for detecting the current of the transmission line, and an impedance of each transmission line from the detection signal of the instrument transformer and the instrument current transformer Compare the impedance change rate of the transmission line calculated by the impedance calculation device and the impedance calculation device with the reference change rate, and if the change rate of the transmission line impedance exceeds the reference change rate, And a transition detector that outputs a transition detection signal when a signal from the impedance change rate determination apparatus is input and signals from all impedance change rate determination apparatuses are input. In-house independent operation transition control device. In the in-house single operation transition control device, which is provided in a power generation system composed of a generator interconnected via a power transmission system having a transmission line and controls the shift to in-house single operation at the time of a power transmission system fault,
An instrument transformer for detecting the voltage of the transmission line, an instrument current transformer for detecting the current of the transmission line, and an impedance of each transmission line from the detection signal of the instrument transformer and the instrument current transformer Compare the absolute value of the impedance of the transmission line calculated by the impedance calculation device and the impedance calculation device with the reference absolute value, and if the absolute value of the impedance of the transmission line exceeds the reference absolute value, a signal is output. And a transition detector that outputs a transition detection signal when a signal from the impedance change rate determination apparatus is input and signals from all impedance absolute value determination apparatuses are input. In-house independent operation transition control device. In the in-house single operation transition control method of shifting the power generation system composed of the generators connected via the power transmission system having the transmission line to the in-house single operation in the event of a transmission system fault,
When the impedance of each transmission line is calculated from the voltage and current of the transmission line, and at least one of the calculated change rate or absolute value of the transmission line impedance exceeds the reference value in all of the transmission lines, An in-house single operation shift control method characterized by outputting a command to shift the power generation system to in-house single operation.

Images