JPS58190240A - Power interlocking device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power interconnection device that transfers power between an AC system and a power conversion device.

Generally, the power conversion system block diagram of the power grid (hereinafter referred to as the grid) and the power interconnection device that transfers power is shown in the first diagram.
It is shown in Figure 2 and Figure 2. In Figure 1, (1) is the power converter, (2) is the connection device, (3) is the grid, and (4) is the breaker that cuts off the connection between the power converter (1) and the grid (3). be.

In the above configuration ξ, normally power conversion fl (1)
Electric power is exchanged between the system and the grid (3) via the connection device (2). At this time, if the circuit breaker (4) interrupts the connection between the two, power cannot be exchanged and the original purpose of the conversion system is lost. The power converter (1) is stopped by detecting that the circuit breaker (4) is in the cutoff state.

However, as shown in Figure 2, in a general power system, a large number of circuit breakers (4) (6) are installed very far away from the power converter (1), and each It is almost impossible to stop the power conversion device 11(1) using the auxiliary contacts of the device. Therefore, during normal operation of the power conversion system, there was no effective means to directly detect when the voltage on the grid side became non-voltage. Even in this case, the output voltage of the power converter (1) is applied to the system up to the power converter (1) and the disconnector (5).
A dangerous situation exists in which heavy pressure is still being applied even when the breaker is opened, and this was a major drawback of conventional systems.

The present invention has been made to solve the above-mentioned drawbacks.
The normal automatic control loop of the power converter that transfers power to and from the grid is used to detect when the voltage on the grid side has become non-voltage (hereinafter referred to as reverse pressure detection), and the power converter is immediately activated. Provided is a power interconnection device that can improve safety by stopping or cutting off between a power converter and a power grid.

The figures will be explained below. In FIG. 8 and FIG. 4, (6) is a breaker that can cut off the cutoff signal;
8. The output voltage signal Sl of the power converter (]) is the system voltage signal supplied by the system (3), and (7) is the system voltage signal supplied by the system (3).
A power conversion section consisting of a semiconductor element such as a TO or a transistor, (August) a control section of the conversion section (7), (9) a first detection section that detects the output voltage signal 8, and αQ a system voltage. The second detection unit that detects the signal s2 (b) converts the output of the detection unit (9) (resultingly 8.) into the output of the second detection unit (2) (resultingly s2). ), @ is the way the candy detection part (9) comes out (as a result, Sl
) is within the allowable value with respect to the specified value K. In this way, the output voltage signal S, is the system voltage signal 8. This is an adversarial system that is configured to follow.

Next, the operation will be explained. In Fig. 4, when the conversion system is operating normally, the automatic control circuit section is configured with a feedback circuit so that the lees follow evenly (so that Sl follows 4), and operates stably. For example, let us explain the case where the operation 81=8! is performed. Both detection i (9) (transfer function G of 10, and 0
1 are equal and therefore stable with F=R. For some reason, the gift is 78. At that moment, 8
increases by ΔE, and the input to the automatic control circuit aυ increases by ΔB. As a result, the output of the automatic control circuit αυ increases and is controlled so that 8,=B+ΔB. 81 is ΔS1
The same operation can be performed stably even in the case of a change in the amount of time.

This is because the reactor (2) exists between Sl and Heto, and moreover, 8□ and 8. This is because they can take independent values without interfering with each other. In other words, connection bag f! 1 (2J) By exchanging active power and reactive power between the SI and the source, 81 and 82 can take independent values.

However, when the heavy pressure supplied by the grid becomes non-voltage, 8.
And 8! It becomes impossible to exchange power between the 8.
=8. become.

This means that if R4F occurs due to a disturbance, etc., the automatic control loop will not operate properly and s, == 8. This means that the control system will diverge as it is. That is, if R)
In the case of F, if F is increased, the entire system operates as s increases, but since there is no power exchange between Sl and the original, 8□ also increases by the amount of increase in Sl, resulting in This results in an unstable system in which disturbances are not suppressed.

Therefore, since the value of F that can be taken in a normal case is known in advance, by comparing and determining this value with the normal if in the comparison/discriminator (2), it becomes possible to detect the back pressure.

However, if there is no disturbance at all, the value of F may not deviate significantly from K, although it is unstable.

FIG. 5 shows another embodiment, 81 and 8. In this example, C is added to force a difference between the values of . If 6 has a difference in voltage magnitude, 8□ and 8. When reactive power is exchanged between C and C causes a difference in the phase of the voltage,
81 and 8 through the connecting device (2)! Active power is exchanged between the Therefore, when the grid becomes voltageless,
Although power is exchanged between Sl and 82, the automatic control system diverges and a cutoff signal is output.

That is, the automatic control system in Figures 4 and 6 is a voltage control system that controls the magnitude of voltage, or a phase control system or frequency control system that handles the phase of voltage.

By using a pure system or a power control system that handles both, it is possible to easily detect no-voltage in the system (reverse pressure detection). In addition, in the case of a phase control system, generally the PL
L circuits are often used.

This is a converter that originally operates stably in a transverse system.
This takes advantage of the fact that the system changes in a self-limiting manner and becomes unstable due to no voltage in the system.

The present invention can be applied to all power interconnection devices that are connected to the grid and exchange active power and reactive power, such as static non-active power generators! (abbreviation 8VG
), and when applied to the power conversion device of a solar power generation system, it exhibits great effects.

However, in Figures 4 and 6, even if a cutoff signal occurs and the converter (1) stops or the breaker (6) trips, it may be difficult to say that back pressure has been detected. . For example, it may be due to a failure of the converter gIt(1) itself or a temporary disturbance on the grid side. Therefore, as shown in Figure 6, the system (3) and the breaker (6
), an eighth detection unit (to) is provided for detecting the voltage between the
AND circuit α
If it is determined by ◆, a complete reverse pressure operation of 1 m can be performed. (to) is a means of displaying the counterpressure praise motion.

Note that even if the reactor (2) in the figure is a transformer with a built-in reactance, the operation is exactly the same.

[Brief explanation of the drawing]

1 and 2 are block diagrams showing a conventional power interconnection device, FIGS. 8 and 4 are block diagrams showing a power interconnection device according to the present invention, and FIGS. 5 and 6 are block diagrams showing a power interconnection device according to the present invention. FIG. 3 is a block diagram showing another embodiment. In the figure, (11 is a power converter, (2) is a connection device, (3) is a power system, (4) and (5) is a breaker with auxiliary contacts, (6) is a trippable breaker, ( 9)
QO is a detection unit for the output voltage signal of the power converter, and QO is a detection unit for the system voltage signal supplied by the power grid. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Makoto Kuzuno - Figure 1 No. 2 ['yl Figure 3 16 Figure 4 1 - -----11--------
Figure 5

Claims (1)

[Claims] (1) In a device that connects an AC power system and a power conversion device via a connecting device to exchange active power and reactive power, the voltage supplied from the power system is zero. A power interconnection device configured to detect with a detection device that the voltage has become low, and disconnect the power conversion device from the power grid. (2) The power interconnection bag wt0(3) according to claim 1, wherein the connection device is an AC reactor.
2. The power interconnection device according to claim 1, wherein the connecting device is a transformer having a built-in beam actance. (4) an automatic control circuit in which the detection device uses a voltage signal supplied from the power system as a reference input signal and a voltage signal corresponding to the output voltage of the power conversion device as a feedback signal;
9. The power interconnection device according to claim 1, further comprising a circuit for detecting that the voltage signal is outside a specified value. (5) The power interconnection device according to claim 4, wherein the automatic control circuit controls voltage. (6) The power interconnection device according to claim 4, wherein the automatic control circuit performs phase (frequency) control. (7) The power interconnection device according to claim 4, wherein the automatic control path is an active power control circuit or a reactive power control circuit that simultaneously controls voltage and phase.