JPS62222166A - Ac signal detector - Google Patents

Abstract

PURPOSE:To make generation of a harmonic wave unstability phenomenon hard, by using AC voltage or AC current signal and making integration every one-half period. CONSTITUTION:Voltages of R, S, T phases of the electric power-line bus 300 are applied to an auxiliary transformer for instrument 1110 of an AC signal detected 1000 via a transformer for instrument 120 and issued out as AC voltage signals epu, eov and eow. The primacy coil of the transformer 1110 is connected in delta. A phase detector 1120 introduces signals eou, eov and eow and issues out a phase signal theta1 by synchronization with the AC current. A timing generator 1140 generated timing signals TP1-TP3 connecting and disconnecting analog switches (SW) 1132-1134 of an integrating circuit 1130 from a signal theta1 and in the circuit 1130, the signal eou is introduced into an integrator 1131 via a SW 1132. An output signal VUBUS of the integrator 1131 becomes the output signal of the circuit 1130 via SW 1134 to be introduced into a sample holding circuit 1150. In the circuit 1150, by a signal TP3, the signal VUBUS of the integrator 1131 is sampled and then, it is detected as a mean signal VRBUS of one-half cycle of the R-phase voltage of the bus 300.

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to an average value or value of an alternating voltage or an alternating current used in a control device such as a static passive power compensator that controls reactive current flowing into a power system by controlling the phase of a control rectifier. The present invention relates to an AC signal detection device that detects an effective value. [Technical background of the invention and its problems] In recent years, reactive force compensators (SVC) using controlled rectifiers have been developed.
:5tatic Var Compensator (hereinafter abbreviated as SVC) is used as a power system stabilizing device in various countries, and is highly effective in improving power system stability and suppressing power fluctuations. First, regarding the main circuit configuration of the SVC and the operation of the control device -
Explain an example. FIG. 3 is a diagram illustrating one configuration example of the main circuit of the SVC. FIG. 4 is a diagram illustrating a conventional example of an SvC control device. Figure 5 is a diagram explaining the control characteristics of SvC, Figures 6 and 7 are diagrams explaining the load characteristics of the power system, and Figures 8 and 9 are the control characteristics of SVC and the load characteristics of the power system. By. This is a diagram explaining the operation of SvC. 10 in Figure 3 is the thyristor control reactor (
(hereinafter abbreviated as TC), and thyristor U. x, v, y, w, z handle axle L1. L2. It is composed of L3. Thyristor U and X1 Thyristor V and Y
1 Thyristors W and Z are connected in anti-parallel to υ
, by controlling the firing phase υ, reactors Ll, L
2. The current flowing through L3 is controlled. 20 is a fixed capacitor (hereinafter abbreviated as FC), which is composed of capacitors CI, C2, C3, and a circuit breaker CB.几, S, T are AC lines. 10
0 is the 5V (4) main circuit, TCR10 and Fe12
It consists of During operation of the SvC, the breaker CB is closed, Fe12 is connected to the AC lines S, T to generate phase leading reactive power, and TCRIO is phase controlled to generate phase lagging reactive power. Since the lagging reactive power is controlled by controlling the phase of TCRIO, the SVC 100 can generate from the leading reactive power to the lagging reactive power on the AC lines JS and T. FIG. 2 shows a control device for the SVC. Devices with the same functions as in FIG. 3 are given the same numbers. 300 is a power system bus, 310 is a main circuit transformer, 110 is an SvC control device, 120 is a voltage transformer, 130 is a voltage transformer, 111 is a system voltage detector,]
12 is a voltage reference setter, 113 is an SVC current detector, 1
14 is an amplifier, 15 and 116 are adders, 17 is an integrator, and 118 is a firing angle side #. Fourth
In the figure, the power system bus 300, main circuit transformer 310, voltage transformer 20, voltage current transformer 130, and SVC king circuit 100 are shown in a single line diagram. Power system bus 3
The voltage of 00 is detected by the grid power detector 111 as the υ thread voltage effective value VBuq through the instrument transformer 120, and the voltage reference value Vref from the voltage reference setter 112 is detected.
is subtracted by the adder 115, and the voltage error signal becomes Δ■
is obtained. On the other hand, the current flowing through the SvC main circuit 100 is detected by the SVC current detector 113 via the instrument current transformer 130 as an SvC current effective value l5vc, which is multiplied by Ks by the amplifier 14, and the slope reactance signal (
Isvc*KS) to the adder 116. The adder 116 adds the voltage error signal ΔV and the globe reactance signal (SvC*KS), and then uses the output signal as an input signal to the integrator 117. The output signal of the integrator 117 is the TC required to keep the error signal ΔV within a predetermined range.
This is the TC control signal QTOR that determines the slow phase reactive current output by R10. The firing angle controller 118 outputs firing pulses to each thyristor of the TCR 10 based on the phase of the system voltage and the TC control signal Q7oa. FIG. 5 is a diagram illustrating the voltage-current characteristics of SvC produced by the SVC control device of FIG. 4. In Figures 5 (a), (b), and (C), the vertical axis represents various effective system voltage values, and the horizontal axis represents effective SVC current values.
svc), the SvC current effective value is the voltage-current characteristic of SvC when the lagging current effective value is a positive value, the leading current effective value is a negative value, and the gain KS of the amplifier 114 in FIG. 4 is 0. It is. FIG. 5(a) shows a state in which the TCRIO of FIG. 4 is not operating, that is, each thyristor U, X, and V of the TCR10. This shows the characteristics in a gate block state where no ignition pulse is applied to y, w, and z, and the relationship between the effective value of the reactive current flowing through the FC and the effective value of the system voltage VBu8 is given by straight line A. The effective value of the SvC current at the voltage reference value Vref in FIG. 4 is 5vC1. Figure 5(b) shows Fe1
Figure 2 shows the relationship between the effective value of the reactive current flowing through TCRIO and the effective value of the system voltage vSvC when the circuit breaker CB in No. 2 is open.
l, L2. When the maximum current flows through L3, which is the minimum value, is the characteristic when the firing angle reaches the maximum value, S in Figure 4.
By controlling the VC control device 110, the characteristics shown by the solid line 2 are produced. The SVC current effective value is l5vcz when the firing angle reaches the minimum value at the voltage reference value Vref.
, when it reaches the maximum value, it becomes 5vc3. Figure 5 (C
1 is TCRt. is in operation, and the characteristics are O and A with the Fe12 circuit breaker CB closed, which is a combination of the characteristics A in (a) and the characteristics in (b). The SVC current at the current reference value Vref is l3VC4 when the firing angle reaches its maximum value.
, Tsvc5 when the firing angle becomes the minimum value. I 5vc2- l5vc3 = 1svc4- Eng 5
The relationship vc5 is established. Note that the phase control of the TCRIO thyristor cannot be performed between the points B and C and the point C and zero of characteristic O in the diagram (C), and the function of stabilizing the power system cannot be performed. Only the '1rCRIQ thyristor phase control can be performed and the power system stabilization function can be performed. Next, to explain the operation when using SVC as a power grid stabilizing device, we will explain the SVC of the power system bus.
The voltage fluctuations at the installation point are shown in FIGS. 6 and 7. In FIG. 6, 400 is a generator, 500 is a power system line (impedance zT), 600 is a variable reactor load, and point A is the SvC installation point. Departure'+! 1d400 generates a voltage E, and if the current flowing through the line when the variable reactor load 600 is a predetermined value is In, the voltage at the SVC installation point is expressed as V=E-Z7-In. Figure 7 is a diagram showing the voltage-current characteristics of the SvC installation point when the generator voltage E fluctuates.
When Eo - ΔV, the characteristics become as expected. Figure 8 is a diagram for explaining the voltage suppression effect of SVC, where the mixed pressure reference Vref in Figure 4 is replaced by the generator voltage g in Figure 7.
This is the case when it is set equal to o. In Figure 8, SvC is Sv in Figure 7 due to the characteristic O of SvC.
If the voltage at installation point C increases by ΔV, the delay current I,
flows, and if the voltage drops by ΔV, the leading current ■
2 is applied to set the grid voltage VBus to the voltage reference [Vref
It shows that FIG. 9 is a diagram illustrating the operation of the SVC when the gain Ks of the amplifier 114 in FIG. 4 is not made zero. However, this is the voltage-current characteristic of the SVC, and as the gain Ks of the amplifier 114 is increased, the slope of the corner point C and the corner point B becomes larger with the voltage reference value Vref as the axis. Comparing FIG. 9 with FIG. 8, when the gain Ks is a predetermined value other than zero, K is SV even if there is a variation ΔV in the generator voltage.
C does not suppress the voltage at the installation point to the reference voltage Vref K, but suppresses it to a point deviated from the reference voltage Vref by Δv1, but even if the variation ΔV fluctuates sharply, the SVC's It can be seen that the control is working. It has been found that the characteristics of the drain shown in FIG. 9 are excellent characteristics for stabilizing the power system. As described above, SVC is a device that is effective in stabilizing system voltage and suppressing power fluctuations, but it has the following drawbacks. That is, the AC voltage of the power system bus 300 and the SV
When the SvC current from C100 contains a harmonic component, if the harmonic component is not sufficiently removed by the system voltage detector 111 or the SVC droplet detector 113 in the SVC control device shown in FIG. is amplified by the integrator 117 and SvC control is performed, so that the power system bus 300 has 5
This is a problem in that connecting VCIOO actually increases harmonic components, inducing a so-called harmonic instability phenomenon. It is well known that the most severe harmonic instability phenomenon is caused by low-order harmonics such as the second or third harmonics with respect to the fundamental wave of the AC voltage of the power system bus 300. [Object of the invention] The present invention has been made to solve the above-mentioned problems.
When detecting the average value or effective value of alternating current voltage or alternating current, an alternating current that can remove harmonic components that are integral multiples of the second or third harmonic relative to the fundamental wave component of the grid voltage. The present invention aims to provide a signal detection device. [Summary of the Invention] In an AC signal detection device that detects the average value or effective value of AC voltage or AC current, the instantaneous value of AC voltage or AC current is detected by either the primary winding or the secondary winding connected in delta. It is equipped with a phase detector that detects the phase of the AC voltage as an AC voltage signal or AC current signal through a voltage transformer or current transformer, and detects the phase of the AC voltage from the phase detector. By obtaining the phase signal for each phase signal and integrating the AC voltage signal or AC current signal for each half period using an integrating circuit, the second phase signal for the fundamental wave component of the system voltage is obtained.
It is possible to detect alternating current voltage or alternating current from which harmonics or harmonic components that are an integral multiple of the third harmonic are removed. [Embodiment of the Invention] An embodiment of the present invention is shown in FIG. Devices that are the same as in FIG. 4 are designated by the same numbers. In FIG. 1, 1000 indicates an AC signal detection device according to the present invention, including an auxiliary transformer 1110 and a phase detector 1.
120. Integration circuit 1130, timing generator 1140
．． It is composed of a sample and hold circuit 115o. Of these, the integrating circuit 113o is composed of an integrator 1131 and analog switches 1132, 1133, and 1134. AC signal detection device in Fig. 1] 000 is 'deer system bus 3
A half-cycle average value signal vasus of the R-phase voltage of 00 is detected. The voltages of the power system bus 300, S phase, and T phase are input to the instrument auxiliary transformer 1110 of the AC signal detection device 1000 via the instrument transformer 120. eow
is output as The primary winding of the auxiliary instrument transformer 1110 is delta connected. The phase detector 1120 receives the AC voltage signal eQ (J HeOV * eON and outputs a phase signal θ1 synchronized with the AC voltage. The phase detector 1120 is based on the phase detector shown in FIG. 3 of JP-A-55-34851). The timing generator 1140 converts the phase signal θ1 into the analog switch 1132 of the integrating circuit 1130.
゜1133.1134 timing signals TPI, TP2. Generate TP3. Integrating circuit 11
At 30, the AC voltage signal eou is connected to the analog switch 113.
It is input to the integrator 1131 via 2. Analog switch 1133 is provided for resetting integrator 1131. The output signal VIJBυ8 of the integrator 1131 becomes an output signal from the integrator circuit 113o via an analog switch 1134, and is input to the sample and hold circuit 115°. Sample and hold circuit] 150 After sampling the output signal Vt1BUL+ of the a divider 1131 using the timing signal TP3 from the c timing generator 1140, the signal is held and is used as the average value signal VRBUIi of half a cycle of the common phase voltage of the power system bus 300. To detect. , FIG. 2 is a time chart illustrating the operation of the embodiment shown in FIG. [Timing signal generation circuit] At 14°, the timing signal TPI corresponding to the 1800 period during which the AC voltage signal e (, υ becomes a positive voltage) input via the auxiliary instrument transformer 1110 is converted into a phase signal from the phase detector 112o. After generating a timing signal TP3 for a period from time t0 to tl and further generating a timing signal TP3 for a period from time t1 to t2 for causing the sample and hold circuit 115o to perform sampling, a timing signal for resetting the integrator 1]31 is generated. TP2 is generated for a period of time t, while t.Time t
0 is the start time of half-cycle average value detection of the AC voltage signal eOtl. From the time t0 when the timing signal TPI is turned on to the time t when it is turned off, that is, during the period when the AC voltage signal eou is a positive voltage, the analog switch 1132
is closed, and the integrator 1131 is performing integration. When the timing signal TPI turns off at time t1, the analog switch 1132 opens and the integrating operation of the integrator 1131 stops. At this time, the timing signal TP3 turns on, causing the analog switch 1134 to close and the sample hold circuit 115o to start sampling. When the timing signal TP3 is turned off at time t2, the sample and hold circuit 1150 enters a hold state, and holds the sampled signal BUS at a time that is the start time of the next sample.

This signal is held until the R phase voltage average value detection signal V
He will appear as RBIJ8. The operation from time t0 to t3 is repeated every time the AC voltage signal eOU becomes a positive voltage. That is, from time 14, t, and from time 14, t
, from t, from t, from t, from t2, from d, from t, and so on. [Effects of the Embodiment] The embodiment shown in FIG. 1 has the following effects. The 8-phase voltage detection signal VRBυ8, which is the output signal of the AC signal detector 1000 according to this embodiment, has R
Not only are harmonic components that are 3 times the number of walls relative to the fundamental wave of the phase voltage removed, but also harmonic components that are multiples of the wall number of 3 relative to the fundamental wave of the phase voltage are removed.
The effect is that harmonic components that are integral multiples of are also removed. For this reason, the AC signal detector 1000 is connected to SVC1 in FIG.
By using it as the AC voltage detector 111 of the 9SVC 200 and the power system 300, there is an advantage that harmonic instability phenomenon is less likely to occur between the 9SVC 200 and the power system 300. [Other Embodiments] FIG. 10 is a diagram illustrating another embodiment according to the present invention. Devices having the same functions as those in FIG. 1 are numbered the same. AC signal detector 1o01 is AC signal detector 1000
After adding an inverting amplifier 1135 to invert the polarity of the AC signal e□υ, the output signal VXBU! of the analog switch 11340 is outputted via the analog switch 11320, the integrator 11310, and the analog switch 11330e. ] Also■
Like the υBus, it is configured to be input to the sample hold circuit 1150. Also, the timing generator 114
1 are timing signals TP], TP2. In addition to TP3, timing signals TPIO, TP20,
It is configured so that TP30 can also be output. In addition, the OR circuit 150 can perform a sample operation using the timing signals TP3 and TP30. FIG. 11 is a diagram illustrating the operation of the embodiment shown in FIG. 10. Timing signal TPIO is AC voltage signal eo. is on during the negative half cycle of analog switch 1.
By closing 1320, the inverting amplifier 1135 inverts the AC voltage signal e□υ and integrates the signal in the integrator 11310 (from time 1 to t4). When the timing signal TPIO turns off at time t4, the timing signal TP30
turns on, closes the analog switch 1340, and sends the signal vxBus to the sample and hold circuit 1150.
sample. Timing signal TP30 is time 1
When turned off at 41, analog switch 11340 opens,
Sample and hold circuit 1150 holds vxaus. Thereafter, the analog switch 11330 is closed between time t41 and t42 using the timing signal TP20, and the integrator 11310 is set to the initial state, and the AC voltage signal e is indicated by the arrow.
Prepare for integration when OU becomes a negative half cycle. According to the embodiment shown in FIG. 11, there is an advantage that the average value of the AC voltage for each half cycle can be detected at high speed for each half cycle. The above has described an example in which the average value of the AC voltage for each half cycle is calculated, but the square root of the output signal of the sample and hold circuit 1150 is calculated using a signal obtained by squaring the AC voltage signal eou as the input signal of the integrating circuit 11301. By providing a circuit, it is also possible to detect the effective value of the AC voltage. Furthermore, by inputting a signal from an instrument current transformer whose secondary winding is delta-connected to the integrating circuit 11301, the effective value and average value of the alternating current can be detected. [Effect of the invention] In an AC signal detection device that detects the average value or effective value of a transform voltage or an AC current, the instantaneous value of the AC voltage or the AC current can be detected by either the primary winding or the secondary winding connected in a delta connection. It is equipped with a phase detector that detects the phase of the AC voltage as an AC voltage signal or an AC current signal through a voltage transformer or current transformer. AC signal detection is performed so that the average value or effective value of the AC voltage is detected by obtaining a phase signal for each cycle and integrating the AC voltage signal or AC current signal for each half cycle using an integrating circuit. By configuring the device, harmonics of an order of an integral multiple of 2 of an alternating voltage or an alternating current, and 3
Since the average value or effective value is detected by removing harmonic components of orders that are integral multiples of This has the advantage of being less difficult.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining one embodiment of the AC signal detection device according to the present invention, FIG. 2 is a diagram for explaining the operation of the embodiment of FIG. 1, and FIG. 3 is a diagram for explaining one configuration example of the main circuit of the SVC. FIG. 4 is a diagram showing a configuration example of an SVC control device, FIG. 5 is a diagram explaining control characteristics of SVC, FIGS. 6 and 7 are diagrams explaining load characteristics of an electric power system, and FIG. 9 and 9 are diagrams explaining the operation of the SVC based on the control characteristics of the SVC and the load characteristics of the power system, FIG. 10 is a diagram explaining another embodiment of the AC signal detection device according to the present invention, and FIG. 10 is a diagram illustrating the operation of the embodiment of FIG. 10. FIG. 1000... AC signal detector, 111o... Instrument auxiliary transformer, 1120... Phase detector, 113o... Integrating circuit, 1131... Integrator, 1132-1134...
・Analog switch, 1140-timing generation circuit, 1150 sample-hold circuit. Agent Patent Attorney Yudo Ken Chika Hiroshi Mitsumata Figure 2 Figure 3 Figure 4 Figure 6 Figure 7 Figure 8 Figure 9

Claims (1)

[Claims] In an AC signal detection device that detects the average value or effective value of AC voltage or current, the instantaneous value of AC voltage or current is detected by an instrument transformer in which either the primary winding or the secondary winding is connected in delta. Alternatively, it is equipped with a phase detector that detects the AC voltage signal or AC current signal through an instrument current transformer and also detects the phase of the AC voltage, and the phase detector detects the phase signal of the AC voltage every half cycle. An alternating current signal detection device, characterized in that the alternating current voltage signal or the alternating current signal is integrated for each of the half cycle periods using an integrating circuit to detect an average value or an effective value of the alternating current voltage.