JPH0815371B2 - Synchronous input device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a synchronous closing device that automatically closes different power distribution systems in synchronization.

[Conventional technology]

FIG. 3 is a block connection diagram of a conventional synchronous closing device disclosed in, for example, Japanese Patent Laid-Open No. 55-109135. In FIG. 3, 1a is a generator circuit breaker for closing and opening a generator 17, and 1b is a circuit breaker.
Is a circuit breaker for closing / opening the busbars, 2 is a voltage / frequency detecting transformer, 18 is a circuit for converting voltage / frequency analog data into digital, and 6 is input through an analog / digital converting circuit 18. An arithmetic circuit for arithmetically operating data, 19 is a circuit breaker based on the arithmetic result of the arithmetic circuit 6.
An output circuit for outputting an on / off signal to 1a or 1b, and 20 is a load connected to the bus bar.

FIG. 4 is a flow chart of the control operation program of the arithmetic circuit 6 of FIG.

Next, the operation will be described. In FIG. 3, when the busbar circuit breaker 1b is turned on, if two generators 17 are already in operation and the generator circuit breaker 1a has already been turned on, synchronous closing is required.

In this case, the voltage / frequency and the voltage phase of each of the generators 17 are input to the arithmetic circuit 6 via the transformer 2 and the analog / digital conversion circuit 18 according to the closing command of the busbar breaker 1b.

Based on these input data, the arithmetic circuit executes the control in the program procedure according to the flowchart of FIG. That is, first, the establishment of the voltage on the closing side busbar of the busbar circuit breaker 1b is confirmed (step 4-1), and if the voltage is established, the voltage / frequency of the closing side generator is controlled to make it the receiving side. Match it with that of the busbar (step 4-2). If these voltage / frequency differences fall within the tolerance (step 4-
3) Comparing the voltage phases of both buses, predicting the time to the next synchronization point, that is, the phase matching point (step 4-4), and when this predicted time is within the allowable value (step 4-5), Through the output circuit 19, a closing signal is output to the busbar breaker 1b (step 4-6), and the breaker is closed.

[Problems to be solved by the invention]

Since the conventional synchronous closing device is configured as described above, the voltage, frequency and voltage phase of the input side and the input side are directly analog-digital converted, and the voltage difference, frequency difference and phase difference are calculated by the arithmetic circuit. Since it is a method to do, 400H
High-frequency power supplies such as the z system have problems such as poor accuracy in computation and failure in synchronization.

In addition, when the power source of the generator and the grid is unstable or affected by electromagnetic noise, electrostatic noise, etc., the output of the voltage difference, frequency difference, phase difference between the generator and the grid power source fluctuates,
It will include ripple. For this reason, in a conventional device in which all the functions of synchronous closing depend on only the program of the arithmetic circuit, when the voltage difference, the frequency difference, and the phase difference between the generator and the system power supply are out of the allowable values, the allowable values occur by accident. However, there is a problem in reliability, such as a serious accident due to a mistaken input when the allowable value is caused by a circuit failure.

The present invention has been made to solve the above problems, and can be applied to a high-frequency power supply and also to a highly reliable power supply device such as an emergency power supply and an important plant power supply that requires continuous power supply. The purpose is to obtain a synchronization insertion device that can be used.

[Means for solving problems]

The synchronization closing device according to the present invention allows an operation circuit that outputs a synchronization closing signal based on the outputs of the voltage difference detection circuit, the frequency difference detection circuit, and the phase difference detection circuit, which are independent of each other, and the output values of the detection circuits. It is provided with a comparison amplification circuit for comparing with a value and a logical product circuit for obtaining a logical product of output conditions of the respective comparison amplification circuits.

[Action]

The arithmetic circuit according to the present invention outputs a synchronization closing signal based on the outputs of the voltage difference detection circuit, the frequency difference detection circuit, and the phase difference detection circuit, and the AND circuit sets the respective output values of the detection circuit as the allowable values. The synchronization input signal is validated according to the output conditions of a plurality of comparison and amplification circuits to be compared,
The synchronization can be surely performed without any mistake, and the reliability is improved.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a circuit breaker, 2 is a transformer, 3 is a voltage difference detection circuit, 4 is a frequency difference detection circuit, 5 is a phase difference detection circuit,
6 is an arithmetic circuit, 7 to 11 are signals output based on the arithmetic result of the arithmetic circuit, 7 and 8 are voltage increase and decrease signals, 9 and 10 are frequency increase and decrease signals, and 11 is a circuit breaker 1 Input signal, 12
a to 12c are setting devices, and 13a to 13c compare and amplify the respective output values of the voltage difference detecting circuit 3, the frequency difference detecting circuit 4, and the phase difference detecting circuit 5 with the allowable values set by the setting devices 12a to 12c. A plurality of comparison amplifiers, 14 is a logical product circuit that logically ANDs the output conditions of the respective comparison amplification circuits 13a to 13c, and 15 is driven by the output of the logical product circuit 14 to make the closing signal 11 of the circuit breaker 1 valid. An electromagnetic relay, 16 is the synchronous closing device of the present invention, which is composed of each member having the above-mentioned reference numerals 3 to 6, 12a to 12c, 13a to 13c, 14 and 15.

FIG. 2 is a flow chart of a control operation program executed by the arithmetic circuit 6 in the synchronization input device 16.

Next, the operation will be described. When the synchronous closing command (not shown) of the circuit breaker 1 is input while the voltage of both buses is established, the power sources of both buses are supplied to the voltage difference detection circuit 3, frequency difference detection circuit 4, and position through the transformer 2. It is input to the phase difference detection circuit 5. The outputs of the detection circuits 3 to 5 are setters 12a to 12c.
The comparison and amplification circuit 13 is used to judge the allowable value set in
It is input to a to 13c and also to the arithmetic circuit 6.

As shown in the control operation flowchart of FIG. 2, the arithmetic circuit 6 first determines whether or not the voltage difference and the frequency difference are allowable values (step 2-1), and the determination result is NO, that is, the allowable value. If it is large, in order to make this deviation small, a decrease 8 or decrease 10 signal is given to the voltage or frequency “large” side generator, and an increase 7 or increase 9 is given to the voltage or frequency “small” side generator. A signal is output (step 2-2).

If the determination result of step 2-1 is YES, that is, if the deviation is within the allowable value, the phase difference detection circuit 5 predicts the voltage phase matching point of both units, and the operation of the circuit breaker 1 is performed (step 2-3). In consideration of time, the closing signal 11 is output a certain time before (step 2-4).

In parallel with the operation of the arithmetic circuit 6, the voltage difference detection circuit 3
The voltage difference signal from the frequency difference detection circuit 4, the frequency difference signal from the frequency difference detection circuit 4, and the phase difference signal from the phase difference detection circuit 5 are set by the setter 12a.
~ 12c is compared with the allowable value set in the comparison and amplification circuit 13a ~ 13c, and when all are within the allowable value, each comparison and amplification circuit 13
The electromagnetic relay 15 is excited by the output of the AND circuit 14 that logically ANDs the output conditions of a to 13c. Contact 15a of this electromagnetic relay 15
Is connected in series to the output path of the closing signal 11 of the arithmetic circuit 6, the closing signal 11 is closed when the contact 15a is closed.
The circuit breaker 1 closes the input signal as a valid signal only when is output.

In the above embodiment, the input signal backup of the control operation of the arithmetic circuit is an interlock by this contact by exciting the electromagnetic relay within the allowable values of the voltage difference, the frequency difference, and the phase difference. A non-contact interlock may be used. Further, the same effect can be obtained even if the signals within the permissible values of the voltage difference, the frequency difference, and the phase difference are each made into a contact point signal or a non-contact point signal, and interlocking all of these signals with the closing signal.

In the digital control system, the analog system (check by hardware) is also used for the following reason.

The arithmetic circuit 6 is not shown in the figure because of the software processing of the CPU, but it converts analog signals other than the CPU into digital signals, and
It also includes peripheral circuits such as an analog input circuit (A / I input circuit) that inputs to the PU, a digital output circuit (D / O output circuit) that outputs the software judgment result from the CPU, and operates a relay.

Further, the arithmetic circuit performs synchronous closing control as one of electric power system control (monitoring control of voltage, frequency, and electric power of the system), and the processing by the arithmetic circuit is a combination of hardware and software. Yes, it is slower than the output of AND circuit 14, which is a condition check only by hardware.

Therefore, even if a large capacity load such as large capacity motor start occurs during synchronous closing and the phases of both machines do not match, immediate response is not possible and the closing signal is output, resulting in asynchronous closing There is a risk of damage.

In that respect, the analog circuits 13 and 14 respond quickly, and the closing signal 11 can be cut by the relay 15 before the closing signal 11 is output from the arithmetic circuit 6, so that asynchronous closing can be prevented.

Compared to analog processing only, digital processing facilitates data processing, and by combining it with a display, it is possible to display this system power status and abnormal display at the time of synchronization input (display of cause of condition mismatch).

On the other hand, for digital processing, I / O peripheral circuits (circuits other than CPU) are also required, and when these abnormalities occur, synchronization may be mistakenly turned on. For example, if the analog input circuit is abnormal and the voltage difference or frequency difference is large, but the data is the same as the normal data, the CPU trusts the analog input data and outputs a closing signal when a phase matching point is found,
It may also cause large grid power fluctuations.

In this respect, according to the present invention, the output relay 15 of the logic circuit 14 interlocks the closing circuit of the circuit breaker 1 operated by the output of the arithmetic circuit 6. It can be prevented.

〔The invention's effect〕

As described above, according to the present invention, the synchronization input signal is output from the arithmetic circuit based on the output of the voltage difference detection circuit, the frequency difference detection circuit, and the phase difference detection circuit, which are independent of each other, and the synchronization input signal is output from the arithmetic circuit. The output of the detection circuit is judged by the hardware whether or not it is within the allowable value, and it is configured so that the above synchronization input signal is valid on condition that all the outputs are within the allowable value. Even if it is applied, there is no effect of failing to apply the synchronization, and there is no fear of mistaken input, and there is an effect that when applied to the high reliability power supply device, an effective high precision and high reliability can be obtained.

[Brief description of drawings]

FIG. 1 is a block connection diagram showing a synchronization input device according to an embodiment of the present invention, FIG. 2 is a flow chart diagram of a control operation program of an arithmetic circuit which is a constituent element of the synchronization input device of the present invention, and FIG. FIG. 4 is a block connection diagram of the synchronization input device of FIG. 4, and FIG. 4 is a flow chart of a control operation program of an arithmetic circuit which is a constituent element of the conventional synchronization input device. 3 is a voltage difference detection circuit, 4 is a frequency difference detection circuit, 5 is a phase difference detection circuit, 6 is an arithmetic circuit, 11 is a synchronization input signal, 13 is a comparison amplification circuit, and 14 is a logical product circuit. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A synchronous closing device for closing a circuit breaker by adjusting voltage, frequency and phase between different distribution systems,
A voltage difference detection circuit, a frequency difference detection circuit, and a phase difference detection circuit that individually and independently detect a voltage difference, a frequency difference, and a phase difference in each distribution system, and the voltage difference detection circuit, the frequency difference detection circuit, and the phase difference detection circuit. Input the analog output of the circuit and increase / decrease the voltage or frequency of the generator in each distribution system so that the voltage difference and the frequency difference are within the allowable values. Allows the output values of the voltage difference detection circuit, the frequency difference detection circuit, and the phase difference detection circuit to prevent the asynchronous input due to a malfunction of the arithmetic circuit and the digital processing arithmetic circuit that outputs the synchronous closing signal. A plurality of comparison and amplification circuits to be compared with the value, and the synchronization input signal output from the arithmetic circuit is made effective depending on the output condition of each of the comparison and amplification circuits. Synchronous feeding device, characterized by comprising the AND circuit of the decisions made by hardware.