JPH06311656A - Synchronous throw-in system for generator - Google Patents

Abstract

PURPOSE:To provide a synchronous throw-in system which can deal with the combination of arbitrary types of voltage to be detected. CONSTITUTION:A generator voltage VG in a power plant and a system bus voltage VB detected through a high voltage circuit breaker and a station circuit breaker are converted through A/D converters 151, 152, 16 into a sampling data string and the phases thereof are shifted by set amounts at phase shifting sections 241, 242, 25. The bus voltage data is switched at a switching section 26 and the phase difference between both data passed through digital filters 17, 19 is determined at a beat voltage operating section 21. Synchronism is then detected based on the operation results and a generator is thrown into the system in parallel therewith. Difference in the type of line voltage or phase voltage to be detected due to the difference in the system of power plant is compensated for by the amount of phase shift at the phase converting section. The power plant system can detect the bus voltage from the high voltage circuit breaker or the station circuit breaker through the switching section 26.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synchronous closing system for digitally detecting synchronization from a generator voltage and a bus voltage in a digital speed governing / exciting control device and putting a generator in parallel to a system.

[0002]

2. Description of the Related Art The operation control equipment of a power plant is being digitized in order to make it unmanned and improve reliability.

FIG. 2 shows a system configuration example of a hydroelectric power plant. A generator 2 driven by a water turbine 1 is linked to another power system 6 via a synchronous closing breaker 3, a transformer 4 and a high-voltage breaker 5. The voltage of the generator 2 is controlled by the field controller 8 by the automatic voltage regulator (AVR) 7.
The speed control of the water turbine 1 is performed by the guide vane opening degree control of the servo control device 10 by the governor control device (GOV) 9.

The computer 11 performs sequence control from start-up of the turbine generator to parallel load operation or load operation to system dissociation and stop, various monitoring, display control and the like.

The automatic voltage regulator 7 is a voltage generator 2
Captures the current and field voltage or the like, obtains a generator voltage and active and reactive power, etc. In operation, performs a computation of the automatic voltage regulator by comparison with the voltage setting unit (90R) 7 ₁ setting, the field control device 8 Performs phase control.

The speed control device 9 takes in the generator output, the frequency, the guide vane opening signal, and the like, and loads the load setting device (6
5P) 9 ₁ and speed setter (65F) 9 ₂ are compared with the set values to calculate the guide vane automatic opening adjustment, and output control of the servo controller 10 is performed.

The on-site power source of the power plant is taken in from the system via the in-house breaker 12 and the in-house transformer 13 from the main bus and supplies it to the auxiliary equipment in the place. This local power supply may be taken into the transformer 13 from the connection point of the circuit breaker 3 and the transformer 4.

Here, the computer 11 has an automatic parallel function for parallelly inserting the generator 2 into the system in addition to the speed-controlled excitation control, and an automatic uniform speed for adjusting the frequency of the generator 2 to the system frequency. It has means for automatic voltage balancing for adjusting the voltage of the generator 2 to the voltage of the system and automatic synchronous closing for obtaining a closing command of the synchronous closing breaker 3 when the uniform speed and the voltage balancing are almost the same and the phases are substantially the same.

The phase detection for this automatic synchronization input has the block diagram structure shown in FIG. A / D converter 15,
Reference numeral 16 converts the waveforms of the bus voltage V _B and the generator voltage V _G into a sampling data sequence, and the sampling data is subjected to removal of the harmonic components of each order by the digital filters 17 to 20 having a two-stage structure. Then, the beat voltage component is detected by the beat voltage calculation unit 21, and it is determined that the phases match when the period of the beat voltage component is equal to or greater than the set value, and the synchronization input process 22 is entered.

The detected sampling data string is also used for the effective value calculation 23 for the digital protection relay function and the power sharing control. Further, such a synchronous charging process is also applied to a similar method in a thermal power generation facility under digital control.

[0011]

Since the beat voltage method is used for the conventional phase detection for making the synchronization, it is necessary to align the detector configurations of the bus voltage V _B and the generator voltage V _G. Become. For example, if the generator voltage V _G is a detector configuration that detects the line voltage of the generator 2, the voltage detector of the bus voltage V _B also needs to detect the line voltage.

If the bus voltage V _B is provided with a detector for detecting the line voltage, the line voltage and the line voltage will be out of phase synchronization because the line voltage advances by 30 degrees in phase angle. At this time, the detection circuit must be changed, and the circuit design of the synchronous closing device or the detector configuration must be redone for each power station system.

Further, depending on the power plant, the internal circuit breaker 1
2 and high-voltage breaker 5 are often provided. In this case, a synchronous closing process is required for each, and two sets of bus voltage detection circuits are also required.

An object of the present invention is to provide a synchronous closing method capable of coping with any combination of voltage detection.

[0015]

In order to solve the above-mentioned problems, the present invention obtains the phase difference between the sampling data string of the voltage of the generator of the power plant and the sampling data string of the bus voltage of the system by beat voltage calculation. In the synchronous closing method of detecting the synchronization from the calculation result and inputting the generator in parallel to the system, a phase conversion means capable of individually shifting the set sampling data strings by a set amount is provided, and the voltage of the generator is It is characterized in that the difference in the detected phase depending on the type of the detector and the voltage detector of the bus voltage is compensated by adjusting the phase shift amount of the phase conversion means.

Further, the present invention is characterized by comprising switching means for switching sampling data of the bus voltage obtained from the high voltage circuit breaker of the power plant and the bus voltage obtained from the local circuit breaker.

[0017]

The difference in the phase of the sampling data string due to the difference in the type of the voltage detected by the voltage detector is compensated by the phase shift of the sampling data string, and the phase synchronization can be detected with respect to an arbitrary voltage detector.

Further, a system equipped with both the high-voltage breaker and the in-house breaker or a system equipped with either one can be dealt with by switching the sampling data by the switching means.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram of a synchronous detection process according to an embodiment of the present invention, which is applied to a power plant equipped with an internal circuit breaker and a high voltage circuit breaker.

The A / D converter 15 ₁ takes in the voltage V _B of the high voltage breaker 5 and converts it into a sampling data string. On the other hand, the A / D converter 15 ₂ converts the voltage V _B of the internal circuit breaker 12 into a sampling data string. The A / D converter 16 converts the voltage V _G of the generator 2 into a sampling data string as in the conventional case.

The phase converters 24 ₁ , 24 ₂ , and 25 are provided for each A /
The sampling data strings from the D converters 15 ₁ , 15 ₂ and 16 are sequentially fetched and their phase conversion (phase shift) processing is performed.

The switching unit 26 switches and takes out the sampling data sequence shifted in phase by the phase conversion units 24 ₁ and 24 ₂ .
The digital filters 17 and 19 remove harmonics of the input sampling data sequence, as in the conventional case. The filters 17 and 19 may have a two-stage configuration as in the conventional case.

Beat voltage calculation unit 21 and effective value calculation 23
Also, the configuration of the synchronization input process 22 is made the same as the conventional one.

In the configuration of this embodiment, the phase converter 24
₁ , 24 ₂ and 25 compensate the phase difference of the detected voltage by switching the phase conversion processing depending on the voltage type of the voltages V _B and V _G.

For example, when the voltage V _B becomes the detection of the line voltage of the bus bar and the voltage V _G becomes the detection of the line voltage of the generator 2, the voltage V _G advances by 30 degrees in phase angle, and therefore the phase The conversion unit 25 converts the phase of the input sampling data string into 3
The phase processing that delays 0 degrees is performed, and the phase conversion unit 24 ₁ or 2
4 ₂ outputs the input as it is without phase shifting.

On the contrary, when the voltage V _B becomes the line voltage of the bus bar and the voltage V _G becomes the line voltage of the generator 2,
Since the voltage V _B leads the phase angle by 30 degrees, the phase converter 24 ₁ or 24 ₂ performs phase processing to delay the phase of the input sampling data string by 30 degrees, and the phase converter 25 shifts the input. Output as is.

Therefore, the beat voltage calculation unit 2 detects the voltage for synchronizing input regardless of the line voltage or the line voltage type.
To detect the phase difference by 1, the same type of sampling data is obtained by the phase shift processing by the phase conversion unit, and the synchronization detection can be performed.

At this time, the voltage detector does not need to be changed and the functional configuration of the synchronization detection processing block need not be changed, and the phase shift processing of the phase converters 24 ₁ , 24 ₂ , 25 can be switched. It's done.

Further, the difference between the system configuration in which the bus voltage is detected by the high-voltage circuit breaker and the system configuration by the in-house circuit breaker is that switching of the switching unit 26 is sufficient. Even when the detection is switched depending on whether or not it is in the parallel operation state, the switching of the switching unit 26 is sufficient.

Here, the phase shift processing of the phase converters 24 ₁ , 24 ₂ , 25 can be easily performed by switching the read address of the sampling data string and can be set to an arbitrary amount of phase shift. Therefore, when it becomes a unit of 30 degrees, it is realized by switching to obtain a delay of a unit of 30 degrees.

In the embodiment, the switching unit 26 switches the sampling data passed through the phase conversion units 24 ₁ and 24 ₂ , but the switching unit 26 is provided in the preceding stage of the phase conversion unit. The effect can be obtained.

[0032]

As described above, according to the present invention, the phase conversion means capable of individually shifting the set amount of the sampling data string of the generator voltage and the sampling data string of the system bus voltage is provided. , By compensating for the difference in the detected phase depending on the type of the voltage detector of the generator and the voltage detector of the bus voltage by adjusting the amount of phase shift of the phase conversion means, phase synchronization can be obtained even for the detected voltage of any type. Therefore, it is possible to set the amount of phase shift of the phase converter without changing the configuration of the voltage detector when applied to an arbitrary power plant system.

Further, according to the present invention, since the switching means for switching the sampling data of the bus voltage obtained from the high voltage circuit breaker of the power plant and the bus voltage obtained from the in-house circuit breaker is provided, a system having both circuit breakers or a system having only one circuit breaker is provided. The present invention has the effect that the switching means can be switched without changing the system or the synchronizing input device.

[Brief description of drawings]

FIG. 1 is a block diagram of synchronization detection processing showing an embodiment of the present invention.

FIG. 2 is a block diagram of a system of a hydroelectric power plant.

FIG. 3 is a block diagram of a conventional synchronization detection process.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Water turbine 2 ... Generator 5 ... High voltage breaker 7 ... Automatic voltage adjustment device 9 ... Speed control device 11 ... Computer 12 ... In-house breaker 15, 16, 15 ₁ , 15 ₂ ... A / D converter 17, 19 ... filter 21 ... beat voltage calculation unit 24 ₁ , 24 ₂ , 25 ... phase conversion unit 26 ... switching unit

Claims (2)

[Claims] 1. A phase difference between a sampling data sequence of a voltage of a generator of a power plant and a sampling data sequence of a bus voltage of a system is obtained by a beat voltage calculation, and synchronization is detected from the calculation result, and the generator is connected to the system. In the synchronous input method of inputting in parallel, a phase conversion means capable of individually shifting a set amount of both sampling data sequences is provided, and a difference in detection phase depending on the type of the voltage detector of the generator and the voltage detector of the bus voltage. Is compensated by adjusting the phase shift amount of the phase conversion means. 2. The synchronous closing system for a generator according to claim 1, further comprising switching means for switching sampling data of a bus voltage obtained from a high-voltage breaker of a power plant and a sampling voltage of a bus voltage obtained from an in-house breaker.