Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
ELECTRONIC DEVICE FOR RESIDUAL CURRENT CIRCUIT BREAKERS OF TYPE B AND ITS DERIVATIVE
Document Type and Number:
WIPO Patent Application WO/2014/104982
Kind Code:
A1
Abstract:
The subject of the invention is an electronic device for residual current circuit breakers of types A/AC/B/B+/B++, where device enables the implementation of improved methods of protective functions in comparison with the currently known methods of measurement, based on the new detection procedures of constant and pulsating DC differential fault- currents. Device emphasis current transformer (3) for detection of differential currents type B/B+/B++, which core is separated from the core of current transformer (1) for currents detection of type A/AC. The device also emphasis the core and summation current transformer (3) through which all the primary leads of current transformers (1) are conducted for the detection of the differential currents type A / AC and contains a separate secondary coil winding, which is completely separated (galvanic and electrical) of the secondary coil on current transformer (1).

Inventors:
BERTONCELJ, Rafko (Oretnekova pot 5, 4000 Kranj, SI)
VIDENŠEK, Andrej (Dragomelj 122, 1230 Domžale, SI)
VERDERBER, Matjaž (Gorenje 39, 1332 Stara Cerkev, SI)
HUMAR, Janez (Pri malem kamnu 5, 1210 Ljubljana-Šentvid, SI)
Application Number:
SI2012/000066
Publication Date:
July 03, 2014
Filing Date:
December 24, 2012
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
RAZVOJNI CENTER ENEM NOVI MATERIALI D.O.O. (Podružnica Stikalna elektronika, Ljubljanska cesta 24a, 4000 Kranj, SI)
BERTONCELJ, Rafko (Oretnekova pot 5, 4000 Kranj, SI)
VIDENŠEK, Andrej (Dragomelj 122, 1230 Domžale, SI)
VERDERBER, Matjaž (Gorenje 39, 1332 Stara Cerkev, SI)
HUMAR, Janez (Pri malem kamnu 5, 1210 Ljubljana-Šentvid, SI)
International Classes:
H02H3/33; H01F38/38; H01H83/14; H02H1/04
Domestic Patent References:
2012-10-04
2010-02-18
2010-02-18
Foreign References:
DE102005007334B42007-02-08
DE19755857A11999-06-17
DE29705030U11998-07-23
DE102005007334B42007-02-08
DE10215019B42007-05-16
Attorney, Agent or Firm:
PIPAN, Marjan (Kotnikova 5, 1000 Ljubljana, SI)
Download PDF:
Claims:
PATENT CLAIMS

Electronic device for residual current circuit breakers type B and its derivatives, which includes current transformer (3) for the detection of the differential currents type B/B+/B++ and current transformer (1) for the detection of differential currents type A/AC, with the relevant implementing elements

characterized in that,

the core of the current transformer (3) for detection of the differential currents type B is separated from the core current transformer (1) for the detection of currents type A/AC and that the secondary winding of current transformer (3) is fully galvanic separated electrically isolated from the secondary coil of the current transformer (1) .

Electronic device for residual current circuit breaker according to the patent claim 1 ,

characterized in that,

it contains the amplifier stage (4) and device (5) for the generation of the PWM signal, which controls the secondary winding on current transformer (3) and enables conversion of information about fault- currents types B, B+, B++ on the primary side of the transformer (3) into the time-domain space and further processing with digital microcontroller (6).

Procedure for differential fault-currents detection according to electronic assembly according to the patent claim 1 ,

characterized in that,

it implements differential current detection with device (6) based on analysis of the PWM signal, where device (6) operates based on analysis of the PWM signal at regular and irregular mode, where:

- device (5) from predefined properties of RL oscillator forms a time- modulated PWM signal, which carries full information about the differential current type B/B+/B++ occurrence;

- analysis process in the microcontroller (6) allows precise measurement of PWM signal pulse/pause changes from device (5) and a unique decoding of time information about fault-current;

- procedure in microcontroller (6) distinguishes between two operating modes, irregular and a regular mode, where:

- in a regular way algorithm after power-up detects the presence of fault-currents, over a PWM signal quantization with discrete values . When the number of samples or discrete values reaches a final value of N, the algorithm calculating the RMS value of the differential current (RMS value of the duty cycle of all samples), which are then evaluated with the limits, followed by a decision algorithm on turning main switch (9) off or not.

- in the irregular mode procedure of operation analysis detects longer transients at startup/shut-down of the power supply (for example in case of loss of power), detects short transients such as EMC interference, and perceives interferences due to the presence of very large flows of differential currents, because then the frequency of modulated PWM signal sharply increases.

Description:
ELECTRONIC DEVICE FOR RESIDUAL CURRENT CIRCUIT BREAKERS OF TYPE B AND ITS DERIVATIVE

The subject of the invention is an electronic device fault-current circuit breaker for differential currents of types A/AC/B/B+/B++ in RCCB switching devices, where device enables the implementation of improved methods of protective functions in comparison with the currently known methods of measurement, based on new detection procedures of constant and pulsating differential DC currents. The invention belongs to the class H 02H 3/33 of the International Patent Classification.

Technical problem presented by the electronic device after the invention addresses the fault-current detection method of differential current types B/B+/B++ and is related to the process of analog/digital electronics implementation due to the RCCB type B and its derivatives. RCCB switch type B is currently the only known switch on the world market, which is able to efficiently protect life and property (devices and equipment) against direct contact with the phase voltage containing DC component and provides protection against fires and injuries. Built-in analog/digital electronics with its separate current transformer measures the presence of the differential currents in the power grid.

Already known patented solutions for the implementation of RCCB switch type B are related to implementation of analog-to-digital electronic circuits and measurement current transformers for differential fault-current type B detection.

In the patent document DE 10 2005 007 334 B4 2007.02.08 of firm Siemens summation current transformer is defined together with measuring of difference flows. Current transformer uses two windings on one core and differs significantly from the current transformer used in bur invention. In our invention two magnetic cores for the detection of the differential currents of type A and B are used and are also physically separated, as if they were in the Siemens patent windings (2) and (3) separated, but are not. Physical separation of these two cores and windings provides significant advantages in the detection of fault-currents type B and possibility for detection type B derivative fault-currents (B+ and B++).

The Siemens patent document WO 2010/018057 A1 defines detection circuit of breaker that detects differential currents through the voltage drop in the secondary winding/coil of the current transformer. Our invention doesn't detect the voltage drop in the secondary winding of the current transformer but forms PWM frequency modulated signal based on secondary coil current. Information it's converted into time domain where it is possible to accurately perform the evaluation information about fault- current occurrence.

In the patent document WO 2010/018058 A1 company Siemens has defined the procedure for triggering protective residual current circuit breakers, which includes summation transformer and evaluation circuit, which significantly differs from our invention. Siemens process defines square wave pulse generator which output vary to the values that temporal change in current, which is induced by a square wave pulse in 5 the secondary winding (30) for the duration of a square wave pulse and/or pause between two orthogonal pulses each time has a predetermined value. On the basis of this information residual current is evaluated. In proposed invention, the amount of rectangular pulses it's fixed and not adjustable, also the induced current as a basis to generate a PWM signal i o every second changes the shape or/and amplitude.

In the patent document DE 102 15 019 B4 firm Doepke in addition to the basic current transformer W1 auxiliary current transformer W2 is defined, which detects only a flow of higher frequency differential currents of type B. All other currents, the differential detection of type A and type B

15 lower frequency currents is done through the base current transformer W1. In contrast to Doepke submitted invention through the current transformer 1 detects only one differential currents of type A, while B-type currents are detected by the current transformer 3. The execution to DE 102 15 019 B4 has a switch 8, which has to be activated on device 9 to 0 detect currents of type B, otherwise the switch is disconnected from the device 5, as is likely causing interference. Our proposed electronic device enables continuous (continuous time) detection of differential currents types A and B. Electronic device for residual current circuit breakers after the invention makes capturing differential current flows through separate cores over the primary and secondary windings of current transformer on it, for the implementation of differential current detection of types B/B+/B++. Device defines current transformer 3 for detection of differential currents type B with core which is separated from the core of the current transformer 1 for the detection of current flow types A and AC. The device assume core and summation current transformer 3 through which wiring from primary side of current transformer 1 is conducted and contains a separate secondary windings on transformer 3, which is completely separated (galvanic and electrical) of the secondary winding on current transformer 1.

The invention will be further explained on the basis of the implementation examples and images, each of which shows: Fig.1 electronic device of RCCB type B with device labels;

Fig. 2 procedure of PWM signal analysis in the device 6;

In electronic device after the invention, formation of DC current on the primary side of the current transformer 3 is modulated with the signal on the secondary side of the current transformer 3, which is derived from the PWM signal of device 5, amplified on device 4. The size of the differential current flow is presented in time domain as the modulated PWM signal, which is evaluated with digital microcontroller 6. Microcontroller 6 implements an algorithm to detect the differential current flows as well as the realization of additional advanced features of the circuit breaker. Microcontroller 6 allows upgrade of functionality from type B current detection to type B+ (detection of differential currents up to 20KHz) and type B++ (detection of differential currents up to 1 MHz) and performs functionality of selectivity and time delay mode.

Current transformer 1 and detection device 2 assume some already well-known technical solutions and procedures. Current transformer 1 of voltage independent RCCB type A performs measuring of electrical currents, through which at least two electrical conductors are leaded on the primary side winding, which must be monitored. The unit 2 detects the differential voltage-independent currents in the RCCB type A and is linked to tripping relay 8 and to microcontroller 6 for evaluation. Tripping relay 8 and switch 9 to break at least one of the primary conductors are also not a subject of invention.

Current transformer 3 captures differential currents through a separate core and primary and secondary windings on it, in a way to detect differential fault-current types B/B+/B++ based on IEC 62423, VDE 0664- 110 working standard and VDE 0664-400. Current Transformer 3 provides the core current transformer or Summary by which we keep all raw water from the core / current transformer current transformer ratio 1 for the detection of the differential currents type A / AC and contains a separate secondary windings, which is completely separate (galvanic and electrical) of the secondary winding of the current transformer third

Amplifier 4 and device 5 allow separate capture and processing of differential currents type A/AC and type B/B+/B++ providing information on fault-current type B/B+/B++ to microcontroller 6, which carries switching off on one or more network lines via a switch 9. Amplifier 4 is connected to the output of the current transformer 3 for detection of the differential currents of type B/B+/B++, through which the primary side winding at least two electrical conductors are passed, where is necessary to control the occurrence of differential currents. Current transformer secondary winding 3, together with the amplifier device 4 and 5 constitute a serial device oscillation circuit, which generates a PWM modulated square wave signal, where the period is at least twice smaller than the differential current period. For operation of serial oscillation circuit at the inlet of device 5 an amplifier 4 is added to the secondary winding of current transformer 3, which own oscillating signal from tuned device 5 amplifies and controls the power current transformer secondary winding 3. PWM modulated signal from the device 5 leads to the microcontroller 6 for the detection and evaluation. Microcontroller 6 evaluates changes in modulated PWM signal of the serial oscillation circuit, which is directly dependent on the primary differential current on transformer 3, and based on predefined value with a threshold criterion, decides about the next step, affecting the state of tripping relays 8. Figure 2 shows the process flow diagram in microcontroller 6 for PWM signal analysis, where in the device 5 a PWM time-modulated signal is formed from predefined properties of RL oscillator, which carries full information about the differential detection of fault-currents types B/B+/B++. Analysis procedure in the microcontroller 6 allows accurate measurement of pulse/pause changes on PWM signal device 5 and a unique decoding of time information about fault-currents.

Procedure in microcontroller 6 distinguishes two operating modes, irregular and a regular way.

In the regular mode an established algorithm after power up evaluates the presence of fault-current through the duty cycle PWM signal quantization with discrete values. When the number of samples or discrete values reach a final value of N, the algorithm calculating the RMS value of the differential current (RMS value of the duty cycle of all samples), which are then evaluated with the limit values. The algorithm then decides whether it is necessary to switch the breaker off or not.

In the irregular mode of operation analysis procedure detects longer transients at start-up/shut-down of the power supply (for example in case of loss of power), detects short transients such as EMC interference and perceives interferences due to the presence of very large flows of differential currents, because then the frequency of modulated PWM signal sharply increases. Electronic device for protection residual current circuit breakers after the invention enables the realization of new devices or units, analog/digital electronics and procedures that enable unified design of new functionality of RCCB switch type B. New functionality presented by the invention are:

- a1. prevention of transients at on/off switches

- a2. prevention of disturbance impacts (EMC and others) on the operation of the switch

- a3. improved selection of differential current detection

- a4. separate and independent functionality of the type A/AC and type B/B+/B++

The invention also includes the implementation of new units, which are:

- b1. electronic device/unit to capture the differential current flows of type B via a separate current transformer with functionality a4 from the previous paragraph

- b2. electronic device/unit with digital microcontroller and process of differential current detection supplemented with advanced functionality (a1 , a2, a3 in the previous paragraph).