CN2033955U - Reactive voltage synthetical controlling and recording device with micro-computer - Google Patents
Reactive voltage synthetical controlling and recording device with micro-computer Download PDFInfo
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- CN2033955U CN2033955U CN 87212872 CN87212872U CN2033955U CN 2033955 U CN2033955 U CN 2033955U CN 87212872 CN87212872 CN 87212872 CN 87212872 U CN87212872 U CN 87212872U CN 2033955 U CN2033955 U CN 2033955U
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Abstract
The utility model discloses a reactive voltage synthetical controlling and recording device for an electric power system, being an integrally intellectualized device using a micro-computer as a core and additionally composed of a signal detecting circuit, a filter converting circuit, an optical coupling circuit, a power measuring circuit, an A/D converting circuit, a display circuit, a recording and printing circuit, a protection circuit and a control output circuit. The reactive voltage synthetical controlling and recording device for an electric power system can conduct the multiple controlling operations for the controlled objects with different requirements according to the real-time detecting signal of the field or according to the result of the off-line optimization calculation of the computer, having simple operation, easy mastering and abundant recording and printing function.
Description
The present utility model relates to a kind of voltage, reactive comprehensive control and the device that writes down that is used for electric power system, belongs to microprocessor in electric power system On-line Control and recording technique.
In the electric power system most of electric substation (station) all disposed the capacitor group and (or) on-load tap-changing transformer, as improving quality of voltage, adjust reactive power flow, reduce network loss and improving the technological means of transmission capacity.Yet how reasonably suitably controlling these equipment, make every effort to reach best control effect, give full play to its technology and economic comprehensive benefit, is that a significant is a technical task.But the power system voltage wattless automatic control device mostly adopts analog-and digital-circuit at present.Owing to be subjected to the restriction of the logic function of circuit own that voltage, idle Comprehensive Control are difficult to obtain desirable optimum efficiency.China existing 10 kilovolts and above big capacity paralleling compensating device great majority are just controlled to detect busbar voltage.Like this, the reactive power compensation benefit of capacitor often is subjected to certain limitation.Some electric substation (station) has disposed electronic simulation formula voltage, integrated control device for wattless in recent years, and obtains certain effect.The general comprehensive time-sharing control system of voltage power-less that adopts of these devices, its operation limit value are actually by the load peak valley time and work out.Have randomness and dispersiveness because the electric power system actual load changes, this control mode can not guarantee quality of voltage and economical operation fully.In addition, be subjected to the restriction of transmitter precision, it is lower that these install idle accuracy of detection.Be difficult to reach the control requirement of the phase of giving.A nearly period domestic indivedual R﹠D institutions also to begin to repay on probation be power system voltage, the integrated control device for wattless of core with the microprocessor.As Patent Office of the People's Republic of China on October 10th, 1985 bulletin, the patent No. is that the utility model of CN85200038 μ is just for above-mentioned a kind of.This utility model is described by its specification: " promptly by the actual load of microcomputer; by the inverse regulation voltage requirement according to the transformer station of detecting in real time; calculate at this moment the most rational voltage definite value that should keep; and comprehensively judge, determine the lifting of transformer station's load tap changer and the switching of compensation condenser automatically according to detected idle value." but in the electric power system actual motion, not necessarily only carry out voltage, control idle the time by inverse regulation voltage requirements.Consider from the angle of whole power system security economical operation, promptly require some electric substation (as Terminal Substation) to move by the unit controls mode of in-situ balancing, require again some electric substation (as hinge electric substation) by the operation of the limit value of the whole network or localized network calculated off-line (if any needs send idle).And being the utility model of CN85200038 μ, the above-mentioned patent No. do not have this function.Simultaneously, itself does not have idle transform part, and can not detect, judge field position signal, so can't reach rational, safe control purpose.In addition, humorously yet there are no product on the market abroad, also do not see and its operation principle, the relevant written information of manufacture method as electric power system microcomputer type voltage, integrated control device for wattless.
At above all situations, it is the power system voltage of core, reactive comprehensive control and record that task of the present utility model has been to provide a kind of microprocessor system of being formed with microprocessor and the corresponding interface chip thereof.It partly forms holistic control and tape deck by input, filtering, optocoupler, power measurement, analog-to-digital conversion, demonstration, record, printing, signal output, protection and microprocessor system etc.The outstanding feature of this device is: have special input and treatment circuit, detect on-site signal in real time, according to giving adjust timesharing control restriction or computer offline optimization result of calculation, the controlled device of difference being controlled requirement and operational mode carries out complex optimum control and timed print relevant data form automatically.
This device is furnished with following several control operational mode according to different requirements.
(1) voltage list prosecutor formula: comprising there being (1) to carry out the control of voltage list by given voltage operation curve; (2) carry out the control of voltage list by the calculating voltage limit value; (3) carry out the control of voltage list by the inverse regulation voltage mode.
(2) local optimum control mode (i.e. the control mode of being undertaken) by the optimization index of our station; Comprising (1) inverse regulation voltage local optimum control mode is arranged; (2) the local optimum control mode of being undertaken by given voltage operation curve; (3) the local optimum control mode of being undertaken by real-time payload calculating voltage limit value.
(3) optimal control method: comprising (1) inverse regulation voltage optimal control mode is arranged; (2) the optimal control mode of being undertaken by given voltage operation curve; (3) calculate the optimal control mode that the voltage limit value is carried out by real-time payload.
(4) pressure mode: promptly when unreasonable situation appears in limit value or running status, device enters fixedly the control mode of limit value automatically and moves.
This device all can be appointed as manually or operation automatically above various operation control methods.The device panel is provided with the change over switch of various operation control methods.During manual operation, this device prints the content of operation that should carry out, and is carried out by the operations staff.When operating automatically, controller is carried out closed-loop control automatically.
Below in conjunction with accompanying drawing this device is described in detail.
Accompanying drawing 1 is the theory diagram of this device.It is made up of following components.
1) analog quantity is imported, and comprises the voltage U of two transformer high-voltage sides
G, electric current I
GWith the load side voltage U
D, this tittle converts the direct current signal that becomes the line relation with its size to by translation circuit, sends into the A/D change-over circuit, and the computer control parameters needed is provided.
2) measuring power angle circuit.Be to realize voltage, reactive comprehensive control, need look into exactly measure the phase angle, high-pressure side (
).The native system phase angle measurement is to finish by waveform transformation, CTC and interrupt control logic circuit thereof.Since the compensating action of software, certainty of measurement can guarantee＜± 1 °.
3) control output.The computer control output order drives relay array by isolation, power amplifier, and directly to the capacitor group, transformer by-pass cock is separately controlled.
4) on-the-spot home position signal.On-the-spot home position signal is sent into computer interface by the photoelectricity isolation, uses for computer inquery.This part signal by its character respectively by band interrupting channel and be not with interrupting channel.Band interrupting channel main receiving condenser switch position signal, when the capacitor malfunction, the computer processing that can make an immediate response.Be not with the main receiving transformer of interrupting channel position and fault-signal separately, to conclude class and field conditions separately.
5) keyboard, display, function setting switch.The function of keyboard, display is to realize person-machine dialogue.Operation limit value, data necessary are sent into internal memory by keyboard.Display can show contents such as band period limit value, year, month, day, hour, min, second, voltage, electric current, meritorious, idle, power factor by the keyboard request.Function setting switch is to specify the controller running status and hard sign etc. is set.
6) printer interface.Give contents such as the table of adjusting by the printable running-active status of this interface printer, accident record, limit value.
7) motherboard ZPU.ZPU is the controller core parts, is made of Z-80CPU and logical circuit, produces the S-100 bus signal.
In addition, also comprise 14KEPROM, as depositing director demon usefulness, and 4KRAM, as the random memory of depositing limit value and temporal data.
This instrument can divide following a few part on functional module:
1) power supply
2) rectifying conversion
3) ZPU and memory
4) input
5) output
6) A/D conversion
7) panel
1. power supply
Power principle figure as shown in Figure 2.
The required whole power supplys of controller are supplied with in the output of five road direct currents.
The selected logic chip supply voltage of controller is+5V, and in order to improve system reliability and antijamming capability, controller adopts and divides plate unit voltage regulation way.Bus provides+8 volts of DC power supply without voltage stabilizing, each unit independent with its steady to+5V is required for this unit.The controller analog electronics, as operational amplifier etc., employing ± 12V voltage, this power supply processing mode with+5V is identical.
Power supply+12V output is the isolated component use of feedway.
Power supply+use of 24V supply relay magnetizing coil.
Must point out, consider the anti-interference and reliability performance that improves complete machine ,+12V ,+the 24V power supply never allow with ± 18V, ± 12V ,+the 5V power supply has the contact of direct electricity.
2. rectifying conversion
Rectification transformating circuit is with measured alternating voltage and alternating current, is transformed to the direct voltage of pressing linear scale, for measuring relevant power-frequency voltage and electric current.And with high side voltage, current sinusoidal wave conversion is trapezoidal wave with its homophase, with realize the computer measurement phase angle (
1) AC power conversion principle
The alternating current translation circuit as shown in Figure 3.
W among the figure
1Be the elementary winding of current transformer, rated current is 5A, and W4, W5 are the current transformer secondary winding.
Instrument transformer LH separates ac input circuit and translation circuit on electric, and current conversion is become voltage.Resistance R
5, R
29It is the fixedly shunt resistance of current transformer.Full-wave bridge rectifier circuit is by diode D
5～D
12Form, consider that the alternating current translation circuit should be able to tolerate the impact of 16 times of rated current, so brachium pontis adopts two germanium tube series connection.It is as far as possible little to lead these two diode forward resistance, and backward resistance is greater than 500K Ω, and reverse breakdown voltage is greater than 220V.Because the existence of current transformer core magnetization curve start-up portion inelastic region, when the tested electric current of input hour, non-linear relation appears between the input current of current transformer and the output voltage, in order to reduce nonlinearity erron, adopt diode D
34～D
36And R
18Form compensating circuit.In order to reduce the caused additive error of variations in temperature, adopt the less metalfilmresistor of temperature coefficient in the circuit.R
14R
15, C
3, C
4Form dividing potential drop and rc filter circuit.RW
2Be the partial pressure potential device, measure range in order to regulate.
W4 winding output sinusoidal voltage through the trapezoidal wave identical with input sine wave of output behind DW4～DW6 slicing, is used for measuring power angle.
2) AC voltage conversion principle
The AC voltage conversion circuit as shown in Figure 4.
This circuit and alternating current translation circuit principle are basic identical, only are illustrated with regard to difference here:
(1) because tested alternating voltage excursion always about rated value ± 20%, so instrument transformer can not use the start-up portion at magnetization curve, therefore needn't adopt linear compensation circuit.
(2) since AC voltage transformer to bear overload impact less, so the full-wave rectification brachium pontis needn't adopt two diodes to be composed in series.
Low-pressure side voltage conversion circuit principle repeats no more with above-mentioned identical.
3.ZPU and memory
All calculation process of controller are formed in this unit, storage and S-100 bus signal circuit.Can be divided into by function:
1) master oscillator, hour hands,
2) the Z-80CPU processor,
3) the read/write ram memory,
4) read-only memory ROM,
5) RAM stand-by power supply and protective circuit,
6) S-100 bus signal logic and drive circuit.
ZPU unit theory diagram as shown in Figure 5.
The microprocessor core is Z80-CPU and relevant circuit.Z80-CPU can handle 8 bit binary data.It has 16 address wires, and addressability reaches the 64KB byte.Controller takies the 16K memory space altogether.
The master oscillator crystal frequency is 8MHZ, and through obtaining the central processing unit clock signal of 2MHZ after the two-stage frequency division, each clock signal period is 0.5 μ.
When semiconductor memory is had a power failure, content will be lost, and just can't resume operation after re-powering.Controller is to there being limit value, and Status Flag, the RAM of historical data etc. have taked to prevent the safeguard measure of data performance.Circuit as shown in Figure 6.
U
3In be placed with data such as limit value, these data cells do not rewrite and retouching operation when operation.When sending when several to internal memory with keyboard, S1 is positioned at the bond number position, and at this moment R/ W signal works, and can carry out read/write operation.When S1 is positioned at the operation end, R/ W conductively-closed, U
3Only be operated under the mode of reading, new information can't write, even when program out of control, also can not destroy original content.
RAM is by stabilized voltage power supply in the machine and stand-by power supply parallel operation, and makes RAM obtain uninterrupted power supply.If E is a rechargeable battery, then can also pass through D1 branch road floating charge.
In addition, R/ W is by pull-up resistor R
1, R
22, RAM can not disturbed and write error information in power interruptions moment.
4. input (1N)
Input-cell circuitry is seen accompanying drawing 7
Six tunnel analog quantitys of input are by following, delivering to S-100 bus behind isolation and the active power filtering.This part circuit is made of 3U7～3U8 and relevant elements.
The trapezoidal wave of input by forming the square wave identical with trapezoidal wave behind zero-crossing comparator and the photoelectric isolating circuit, is used for measuring the φ angle.3U
9Be zero-crossing comparator, 3D
9～3D
12Play clamping action.
3G9～3G12 photoisolator is provided with in order to prevent momentary pulse from disturbing the φ angular measurement.
The output waveform of four road waveform transformation circuit is identical, but separately all with the sinusoidal wave homophase of input, thereby can determine the size at φ angle by the waveform relativity shift between measuring voltage, electric current.
U1～U
3Be the serial peripheral chip of Z80, its function can be by programming definite and changing, because there is stronger interrupt logic control circuit its inside, so be applicable to finish complexity very much real-time Processing tasks.
3U
5, 3U
12, 3U
13, 3U
15Form the waveform commutation circuit, pass through 3U
5Exporting different codings can be at 3U
15～1(T) export two groups and U respectively
CA, I
AAnd U
CAI
AThe square wave of homophase.
The circuit of measurement power angle φ as shown in Figure 8.
φ＝90｜1－ (4f)/(fN) NX｜
Work as N
X＞(fN)/(4f) time, φ is for lagging behind
During N＜(fN)/(4f), φ is leading
In the formula: f---mains frequency
f
N---high stability clock frequency
N
X---each T square wave (
CA 
B) interior umber of pulse
In fact, mains frequency f is the amount (although very little) of a variation, and the variation of f will cause the error of φ value.So need measure the f value.The variation of f directly influences
CAWidth, by measuring
CAFluctuating range is little, and the mapping fault of waveform can be eliminated by the constant compensation.The current signal amplitude becomes with load condition, and the waveform transformation error is the amount of a variation, follows the tracks of compensation way so adopt.
Utilize 1 passage of the rising edge triggering CTC1 of waveform T to produce interruption.The first, the data of I, II platform transformer unit are gathered and handled to the sampling period respectively, and there are five T interrupt procedures in each sampling period, to finish voltage, current waveform bottom width and N
XMeasurement and compensation calculate, to obtain accurate φ value.
On-the-spot inverse signal is that the running status according to capacitor determines.The state of controlled capacitor reads in CPU by the PIOP mouth.This mouth work prosecutor formula on the throne.The auxiliary node of on-the-spot eight group capacitor switches connects as shown in Figure 9 in the circuit.
Photoisolator separates scene and logical circuit on electric.When on-the-spot node XJ disconnected, G ended, and is output as low level, and panel leds extinguishes; When XJ is closed, R
2By short circuit, the G conducting, G is defeated to be high level, and panel leds is bright, this state can read in computer by the P10-B mouth, to realize inquiry.
5. output (OUT)
Output unit is that the control command that computer sends is moved corresponding circuit breaker, is switched on or switched off the control loop of controlled device, realizes controlled function.In addition, this unit also comprises printer interface and on-load tap-changing transformer position inverse signal interface (if any) separately.
The controlling output circuit rough schematic view is seen shown in Figure 10.
Control output is control production scene equipment directly, and the output of any mistake all can bring influence or accident to production.So circuit and software all should be taked measures necessary.
Full machine reset or when powering on POC one high level pulse appears, make I/O clear terminal CLR a low level pulse occur, thereby make I/O zero clearing, blocking relay.Have only in addition when coded lock is output as " O ", output order could be sent by I/O.So, to make coded lock be output as " O " before the control command output, and make the I/O mouth open.Password is sent through 3U6 decoding gating 4U13 or 4U14 by PIO.
The relay node is output as 2 seconds closures, is realized by Program time delay.For preventing that Program time delay from breaking down, hardware circuit has been done the reserve processing, and relay power is controlled by monostable trigger-action circuit.Monostable time delay is got:
Software time delay＜monostable time delay＜controlled device allows maximum delay.When time-delay surpasses time-delay when monostable, monostable trigger-action circuit resets and makes the relay outage, guarantees closure for a long time of relay.
6.A/D conversion
The A/D converting unit is to convert six tunnel analog quantitys of controller input and 32 tunnel analog quantitys of report printing to digital quantity.The core component of A/D converting unit is ADC1210HCD.
A/D conversion block diagram as shown in Figure 11.
Diverter switch is selected the CD4051 chip for use, by the decoding circuit gating road analog channel of being made up of 9u12,9u13.Certain road analog quantity by gating is sent into the AD1210 input by follower 9U4.
Because the AD1210 output latch does not have ternary function, so, be connected with bus through 9u7,9u8 tristate buffer.
Starting the A/D conversion is to utilize OUT+Y1(U15), this deration of signal is about two clock cycle (about 1us), is not less than 4～5us and start the negative pulse width requirement, so, utilize in addition broadening of u24 monostable trigger.
The CC end is the EOC signal end, when changing, and CC=" 1 ", behind the EOC, CC=" 0 ", this signal can read in CPU by 9u8, also can utilize this signal to produce and interrupt.
The power supply of AD1210 and reference voltage provide after by the 9u5 voltage stabilizing, adopt V here
CC=V
+=+5V.
The AD1210 clock obtains (250KHZ) by the host clock three frequency division.
7. panel
Panel unit comprises
1) 12 light-emitting diode displays
2) 5 * 5 keyboards
3) control cancel switch
4) function setting switch and corresponding indicator light
5) capacitor locations signal lamp
6) alarm lamp
7) reset and connect button
8) calculate reset button
9) close display switch
Panel mainly is made up of the I/O port circuit, in the program it is only exported with input instruction and operates.
Display utilizes LS377 to drive, and the LS377 low-level input current can reach 20MA, and high level only be 6mA, so adopt common anode display (every section glow current＜20mA).D5, D6D7, restriction display currents.The diode forward pressure drop is subjected to current affects less, so also little to other luminous influence when displaying contents changes.Displaying contents can utilize an output order to specify, and section decoding is finished by program.The font table can be found in source program.
Keyboard adopts the non-coded scanning wiring of matrix form, and principle is very simple, can consult TP801 single board computer keyboard note, no longer sets forth here.
Each function setting is by being connected on 6U16, and the P cock on the 6U17 is realized.The flow direction of program is decided in the position (" 0 " or " 1 ") that can in time read in corresponding P cock in the program running.Whether reliably P cock closes, and corresponding indicator light is just bright, can differentiate P cock contact thus.
When starting shooting or powering on, controller produces the RESET signal by circuit shown in the accompanying drawing 12, makes device enter the RSTO program entry automatically.K is full machine reset button.
When program out of control (as endless loop), produce non-shielding interrupt signal by circuit shown in the accompanying drawing 13, just CPU enters regulation unit executive program automatically, the recovery device operation.
The embodiment of this device is as follows:
1. be suitable for electric pressure: high-pressure side: 35 kilovolts～220 kilovolts
Low-pressure side: 6 kilovolts～10 kilovolts
2. idle voltage adjusting device configuration mode:
(1) 1～2 on-load tap-changing transformer and capacitor group;
(2) the capacitor group is only arranged;
(3) on-load tap-changing transformer is only arranged;
(4) some group capacitors.
3. environment for use temperature :-5 ℃～+ 55 ℃
4. input parameter: voltage AC90V～120V
Electric current AC0～5.2A
5. measure error: voltage measurement error :≤0.5%
φ angular measurement error :≤± 1 °
Meritorious, reactive power measurement error :≤2%
Timed print plate table transformed error :≤0.2%
(not containing the transmitter error)
6. time delay of action is 20 seconds to 300 seconds (adjustable); The double action of same controlled device blanking time is 200 seconds to 300 seconds
7. device power supply AC220 lies prostrate, and+10%～-15%, 50HZ ± 2%
In sum,, embodied its novelty and advance, made it more approach actual conditions because this device has been taked above all technical measures.This device model machine is through the laboratory and on-the-spot trial run, and every index all produces a desired effect.
Claims (6)
1, a kind of by being core with microprocessor and interface chip thereof; signal deteching circuit, filtering transformation circuit, photoelectric coupled circuit, power-measuring circuit, A/D change-over circuit, display circuit, record print circuit, protective circuit, controlling output circuit and keyboard, function setting switch, power pack all-in-one-piece are used for power system voltage, reactive comprehensive control and the device that writes down in addition, it is characterized in that:
(1) lifting of control transformer station (institute) on-load voltage regulation variator tap and the switching of compensation condenser have dual mode,
One: on-the-spot live signal carries out filtering transformation, light-coupled isolation behind signal deteching circuit, send into the A/D change-over circuit then, sends signal by CPU at last, the drive controlling output circuit;
Its two: CPU reads after the information that is stored in memory directly drive controlling output circuit;
(2) keyboard and function setting switch pass through interface circuit separately respectively, and switching value information is sent in CPU and the internal memory;
2, device according to claim 1 is characterized in that: in the power-measuring circuit, input voltage, electric current pass through waveform transformation respectively, are added on the CTC chip through the logic control link then.
3, device according to claim 1 and 2 is characterized in that it is to take from on-the-spot voltage transformer and current transformer that signal measures.
4, device according to claim 1 and 2 is characterized in that A/D Transform Sets that device adopts 12 bit resolutions sheet ADC121OHCD intentionally.
5, according to claim 1 or 2 described devices, it is characterized in that address decoding control 74LS273 chip in the controlling output circuit, corresponding signal is isolated amplification output through photoelectricity then, directly drives relay array, and is provided with the password exclusive circuit.
6,, it is characterized in that the running status of electric capacity is read in computer by the PIO-B mouth in the on-the-spot inverse signal input circuit of device, panel leds indication simultaneously according to claim 1 or 2 described devices.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 87212872 CN2033955U (en) | 1987-11-19 | 1987-11-19 | Reactive voltage synthetical controlling and recording device with micro-computer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 87212872 CN2033955U (en) | 1987-11-19 | 1987-11-19 | Reactive voltage synthetical controlling and recording device with micro-computer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2033955U true CN2033955U (en) | 1989-03-08 |
Family
ID=4827466
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 87212872 Withdrawn CN2033955U (en) | 1987-11-19 | 1987-11-19 | Reactive voltage synthetical controlling and recording device with micro-computer |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2033955U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1316714C (en) * | 2002-01-29 | 2007-05-16 | 株式会社日立制作所 | Transformer substation system |
| CN102169163A (en) * | 2010-12-30 | 2011-08-31 | 上海申瑞电力科技股份有限公司 | Alternating-current direct-current adaptive switching value collecting circuit and method |
| CN104333007A (en) * | 2014-11-05 | 2015-02-04 | 国家电网公司 | Reactive voltage controller based on principal and subordinate structure |
-
1987
- 1987-11-19 CN CN 87212872 patent/CN2033955U/en not_active Withdrawn
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1316714C (en) * | 2002-01-29 | 2007-05-16 | 株式会社日立制作所 | Transformer substation system |
| CN102169163A (en) * | 2010-12-30 | 2011-08-31 | 上海申瑞电力科技股份有限公司 | Alternating-current direct-current adaptive switching value collecting circuit and method |
| CN104333007A (en) * | 2014-11-05 | 2015-02-04 | 国家电网公司 | Reactive voltage controller based on principal and subordinate structure |
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| C06 | Publication | ||
| PB01 | Publication | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C15 | Extension of patent right duration from 15 to 20 years for appl. with date before 31.12.1992 and still valid on 11.12.2001 (patent law change 1993) | ||
| RN01 | Renewal of patent term | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |