Four-way electronic switch for tracking balloon borne transmitter using sequential lobe switching

The tracking of meteorological balloons using dipole matrix array antenna by sequential lobe switching with the help of a motor driven mechanical UHF phasing switch had been in operational use in our national upper air network from last 25 years. A solid state four-way electronic switch at 400 MHz using high conductance-high speed switching diodes has been designed to replace the aged motor driven mechanical phasing switch. Microstripline technique has been used in designing UHF switch to achieve proper impedance, matching, routing and addition of UHF signals received from the four antenna bays. For sequential switching of antenna array and synchronisation of data reception and display system the intelligence is generated by a compact logic in-built in the phasing switch. Unlike, mechanical switch, the present system has no switching noise and has low insertion loss (2 dB), thus improving the data acquisition capability of ground reception system. The design of switch is modular, light weight and highly rugged to suit all types of environmental conditions.

Mechanical Switch Based Adaptive Fault Ride-through Strategy for Power Quality Improvement Device

Cascaded H-bridge power quality improving device (PQID) has garnered extensive attention for its flexible electric energy conversion and fast voltage response. However, the failure rate of PQID is relatively high due to the use of large numbers of power electronic devices. This paper proposes a mechanical-switch based adaptive fault ride-through strategy for improving the operational stability and power supply reliability of PQID. According to the features of the topology and working principle of PQID, this paper summarized the types of internal faults and analyzed the characteristics of different types of faults. Based on the shortcomings of existing mechanical switches as a bypass method, corresponding adaptive fault ride-through strategies are proposed for different types of faults, and a comprehensive simulation test has been carried out. The results show that the proposed strategy can adaptively ride through unit faults and effectively improve the output waveform quality during the ride through time.

Analisa Pengujian Kelayakan PMT 150 kV Bay Mandirancan I Berdasarkan Parameter Breaker Analyzer di Gardu Induk Sunyaragi

Electricity is an energy that is very important in all aspects of people's life. PT. PLN (Persero) as a provider and supplier of electrical energy in Indonesia, is absolutely required to supply electricity to the community properly. One of the efforts to do this is to ensure the appropriateness and reliability of the equipment used in the electric power transmission system by carrying out routine testing and maintenance. The equipment that plays a vital role in the electric power transmission system is the Circuit Breaker (CB) because it functions as a mechanical switch used to cut off the flow of the load current which plays an important role when a disturbance occurs to protect other equipment from damage. Therefore, the reliability of this CB must always be maintained. In this study, tests were carried out four times on the CB 150 kV Mandirancan I contacts by measuring the synchronization of working time for open, close, reclose, and OCO (Open - Close - Open) contacts using a Breaker Analyzer measuring instrument. The test results show an anomaly in terms of the synchronization of the contacts, where one of the contacts works faster when it closes due to the longer pull of the motor than the other contacts. To overcome this, it is recommended to reset the Motor Run Limit Switch PMT so that the length of time the motor works is similar in all of its contacts.

Penggunaan SFCL untuk membatasi arus gangguan pada jaringan distribusi terintegrasi dengan pembangkit energi baru terbarukan

ABSTRAK Integrasi pembangkit listrik energi baru terbarukan ke jaringan listrik yang sudah ada dapat menyebabkan kenaikan arus gangguan, mengakibatkan peralatan proteksi yang ada tidak mampu untuk menangulanginya. Hal ini tentunya dapat menyebabkan kerusakan peralatan-peralatan listrik yang dilewati arus gangguan tersebut dan dapat mengakibatkan kegagalan dalam sistem penyaluran daya listrik. Pada penelitian ini dilakukan studi penggunaan peralatan superconducting fault current limiter/SFCL untuk membatasi arus gangguan yang timbul pada jaringan tenaga listrik. Dengan cara memanfaatkan impedansi yang dimiliki oleh SFCL untuk menggerakan mechanical switch (fast switch) sehingga arus gangguan akan melewati current limiting reactor yang terhubung paralel dengan superconductor yang dapat bekerja kurang dari setengah siklus setelah terjadinya ganggun. Pengujian sistem dilakukan dengan beberapa skenario yaitu: 1. sistem tanpa integrasi pembangkit listrik energi baru terbarukan; 2. sistem dengan integrasi pembangkit listrik energi baru terbarukan; 3. sistem dengan integrasi pembangkit listrik energi baru terbarukan dan superconducting fault current limiter. Hasil pengujian skenario 3 menunjukan adanya penurunan arus gangguan yang semula sebesar I = 1,007 kA menjadi I = 0,278 kA dan nilai tegangan sistem yang semula turun sebesar Vrms = 0,856 pu naik menjadi Vrms = 0,96 pu. ABSTRACT The integration of new and renewable energy power plants into existing power grids can cause an increase in fault currents, rendering existing protective equipment unable to cope. This of course can result in damage to electrical equipment through which the disturbance current passes and can result in failure in the electrical power distribution system. This research will conduct a study on the use of superconducting fault current limiter equipment to limit the fault currents that appear in the power grid, by utilizing a very high impedance to drive the mechanical switch (fast switch) so that the fault current will pass through the current limiting reactor which is connected parallel to the superconductor. which can work for less than half a cycle after the disturbance. System testing is carried out with several scenarios, namely: 1. systems without integration of new renewable energy power plants, 2. systems with integration of new renewable energy power plants, 3. systems with integration of new renewable energy power plants and superconducting fault current limiter. The test results of scenario 3 showed a decrease in the fault current by the original I = 1,007 kA to I = 0.278 kA and the value of the system voltage that originally decreased by Vrms = 0.856 pu rose to Vrms = 0.96 pu

System for software-controlled switch with manual override

Smart switch with manual override capability provides a fallback mechanism for users to control household appliances in the event of electronics failure. Essentially, the device is equipped with a single-pole double-throw (SPDT) mechanical switch coupled with electronically-controlled relay. Load current is measured through current sensor connected to the return lines and is constantly read by microcontroller to determine the operational state of the switch and to detect over-current fault. A hardware prototype was developed that uses open-source software to ease system development. Lab testing verifies functional operation of the prototype meets design objectives.

Intracellular softening and fluidification reveals a mechanical switch of cytoskeletal material contributions during division

The life and death of an organism depends largely on correct cell division. While the overall biochemical signaling and morphological processes during mitosis are well understood, the importance of mechanical forces and material properties is only just starting to be discovered. Recent studies of global cell stiffening during cell division may imply an understanding of the cytosol mechanics that is mistaken. Here we show that in contrast to the stiffening process in the cell cortex, the interior of the cell undergoes a softening and fluidification that is accompanied by a decrease of active forces driving particle mobility. Using optical tweezers-based microrheology we capture the complex active and passive material state of the cytoplasm using only six relevant parameters. We demonstrate that the softening occurs because of a surprising role switch between microtubules and actin, where the intracellular, actin-based mechanics is largely controlled by a formin-mediated network.