Combined integrated
At present, when the electrical parameters such as current and voltage are collected online, the external current transformer, the voltage transformer is generally used, and the maximum disadvantage of the external voltage transformer is that the fuse is easy to blow, especially in lightning. Under the weather, the damage chance is large, affecting the voltage measurement reliability. Further, the external voltage transformer is costly, especially on the distribution line, measuring three external voltage transformers or three-phase five-phase voltage transformers when measuring three-phase voltage and zero sequence voltages, and the user needs special Consider the installation location and require regular maintenance.
Our company has independently developed a combined current, voltage sensor, which can simultaneously acquire three-phase voltage and three-phase current signal simultaneously, replacing traditional current transformers and voltage transformers. It is characterized in that the current transformer coil and a copper foil ring are used; when the combined current voltage sensor fixes the primary side guiding member of the high pressure switching device, when the primary side conductive member of the high voltage switch device flows through the AC current, The current transformer coil induces an alternating current, and outputs a secondary current that changes with the primary current size on the current transformer lead, which is used to protect the measurement and control device; when the primary side conductive member of the high voltage switching device plus AC voltage In the copper foil ring, the AC voltage is induced, and the secondary voltage varying as one voltage size is output on the shield line, and the control device is supplied to voltage collection.
This combined current voltage sensor is simple, mechanical properties are stable, and the maintenance cost is reduced, and the manufacturing and installation process is relatively simple.
High voltage circuit breaker single-phase ground protection measurement and control system
At present, the current small current connection device, mostly through an external voltage transformer, current transformer concentrates the zero sequence voltage of the substation and the zero sequence current of each outgoing switch. When the power grid occurs in a single phase failure, the fault line is judged by the ratio of the grade method, the phase method, or the ratio phase ratio phase. The correct line of the existing small current pickup device is less than 50%, and many power supply sectors are still using the larier method to determine the failover outline.
Our company has developed a high-voltage circuit breaker single-phase grounding protection and control system with independent intellectual property. The protection and control system and the circuit breaker body adopt integrated design. It collects three-phase currents on the switching line on the distribution line in real time. The voltage value, and extracts the fundamental wave of zero sequence voltage and zero sequence current, 3 times and 5 harmonics and zero-sequence power, according to the fault characteristics of single-phase fault, by zero-sequence voltage, zero-sequence current based base wave and 3 times and 5 harmonics are start-up values, and the zero-order power direction is determined, accurately determine the discharge device load side fault, send a single-phase protection alarm signal or give the protection trip command to realize single-phase alarm and protection .
This single-phase ground protection controller only needs to collect the electrical feature amount of this line, rather than centralizing the electrical feature amount of all outlines of the substation; when the line load side is uniformly fault, the single-phase ground protection controller can detect in time Out, issue alarm or protect the trip command; and when the power side of this line is single-phase failure, the circuit breaker does not operate, thereby achieving accurate identification failure, quickly locating the fault line.
Quick protection control system
Data acquisition and processing units are usually based in the currently used high-voltage circuit breaker protection control system.AC input signal above 1 week / 20ms (20ms), calculates the various electrical feature amounts required to extract the desired electrical feature by FFT transform (or DFT transformation, root calculation, etc.), and then according to the protected retreatment, the setting of the action, etc. Determine whether to send the protection action outlet signal; the switch output circuit usually uses an output relay, the intermediate relay realizes the separating brake drive, due to the output relay, the mechanical contact of the intermediate relay has a certain response time, the delay time of the general output relay is 5ms The above, the delay time of the intermediate relay is more than 8 ms, that is, the protection control system has a fault current from analog input circuit to give a divided clock drive signal, and at least 30.5 ms or more delay (ignore software calculation time) . The response time increases the impact time of the fault current to the grid, reducing the actual operating life of the grid, and is not conducive to fast fault isolation.
Our company has developed a high-voltage circuit breaker rapid protection control system with independent intellectual property, which makes the protection control system from analog input circuit from analog input circuit from an analog input circuit to a fracture drive from an analog input circuit by shortening the measurement and protection operation. The delay time of the signal is reduced, thereby shortening the impact time of the fault current to the grid to achieve rapid protection.
The separation brake circuit in the switch output circuit of the rapid protection control system uses an electronic divider brake circuit instead of conventional mechanical contact relays and constitutes a fast output circuit of the switch. At the same time, the half-wave symmetry is used and the recursive operation, and the first half of the waves are calculated in each sampling point.10ms) The various electrical features required for time, thereby shortening the time of fault current measurement and issuing protection control signals. When the fault current is greater than the current value, the delay time of its protective action signal will be less than 10 ms + 20ms / per week wave sample point, and the electronic separator brake circuit is used instead of the conventional mechanical contact relay constitutes a quick output circuit, The delay time is less than 0.1 ms, thereby shortening the protection control delay time. The circuit breaker rapid protection control system has a fault current from an analog input circuit to give a split drive signal, and only 10.4 ms of delays in the slowest (when the sample point is 64 points). Therefore, the fault line can be quickly isolated, and the holding time of the power grid fault current is reduced, thereby achieving rapid protection control.