Sparks Electrical News October 2017

ENERGY MEASUREMENT AND SUPPLY

18

MEECO INSTALLS LARGEST SOLAR PLANT IN ZIMBABWE

A fter equipping the facility of a Zimbabwean company with the largest solar energy plant in the country to date, Swiss-based meeco Group will now implement a further extension at the same clean energy installation and is about to ex- ecute a third PV facility with a capacity of 330 kWp. To ensure a cost-effective and predictable energy supply, meeco installed an off-grid sun2live energy generating system with a total capacity of 216 kWp in the first quarter of this year. To meet the client’s requirements, the eco-friendly clean energy solution was installed at two different locations. The first 152 kWp sun2flow solar system was placed close a lake, where the generated renewable energy drives a pump to process water. Another 64 kWp ground-mounted sun2live solar power solution was installed at the company’s management facility to shave off costs arising from the generator’s diesel consumption. A third solar facility, with a total capacity of

330 kWp, is about to be installed at another client site. The sun2live/sun2flow combination will immediately displace electricity coming from the grid and will reduce electricity costs. As a combination of the energy generating system sun2live and the solar water pumping solution sun2flow, the solar facility will supply power for the entire farm, including the pumps. The meeco Group will connect advanced and reliable frequency converters (Aqua Drive), which will run the existing water pumps to secure the water supply of the client. With an integrated speed controller, the Aqua Drive regulates and adjusts the voltage, which is variable and dependent on the current load of the pumps. This allows the water pumps to run efficiently on photovoltaic or grid supply. The 330 kWp sun2live/ sun2flow facility is designed to allow for future extension.

Enquiries: www.meeco.net

FOURTH GENERATION OF BATTERY DISCHARGE TESTER FROM MEGGER

POWER-STAR ONLINE ENERGY METER

equipment it serves. Via a dc clamp-on ammeter, TORKEL measures total battery current while regulating it at a constant level. Furthermore, the high discharge capacity gives the opportunity to shorten the test time. Discharging can take place at up to 220 A, and if higher current is needed, two or more units or extra load units, TXL, can be linked together.

The Torkel 900 is Megger’s latest battery discharge tester, which gives comprehensive results when testing battery capacity. The Torkel concept was released in the 80s as the first portable battery discharge tester that had automated resistance regulation to be able to keep constant current. The Torkel 900 series is the 4 th generation product and with that a new way to regulate the discharge current is introduced, with the benefit of a world leading dynamic power/voltage range. Furthermore, the design has enhanced safety features including spark free connection and emergency safety fuse. Stationary back-up batteries are present in substations but also many other areas. The Torkel 900 series is used to perform load tests, or discharge tests which is the only way to determine a battery system’s actual capacity. Tests can be conducted at constant current, constant power, constant resistance or in accordance with a pre-selected load profile. Together with the cell voltage logger, BVM, now connected directly to the

Enquiries: mesales@megger.com

The Power-star online energy meter being assembled.

T he Power-star online meter is a locally manufactured meter that provides real-time data, which can be used for a variety of purposes. Once the meter is installed on site, users receive a secure login account, where they able to keep track of their energy usage. Energy consumption can be remotely monitored, which allows engineers and managers to fix problems in the existing energy infrastructure without the delay of collecting data, as the information is updated every 60 seconds. Various reports can be pulled from the online interface, including financial reports, trend reports on usage, and summaries on general consumption. Electricity bills can be compared with bills from the user’s local council and verified. Architecture of the meter: • The Power-Star unit is a purpose built data logger, with an integrated GSM Modem. The meter is equivalent to a Class 1 metering standard (within 1% accuracy). All en- ergy metrics are measured except for harmonics. • It uses GPRS with an on-board modem to transfer energy readings every 60 seconds to a central MS SQL server. • The data is processed and analysed upon arrival. The infrastructure is secure, and independently hosted with regular backups. • It can be accessed through any web browser and the data includes energy metrics, environmental information as well as financial and billing data. • The benefits of the meter are independent communication and real time data that is available to users.

Torkel 900, it becomes a complete stand-alone discharge test system. The Torkel is connected to the battery, the discharge current and the alarm levels (voltage, capacity, time) are set. After starting the discharge it keeps the current constant at the preset level. When the voltage drops to a level slightly above the final voltage, it issues an alarm. If the voltage drops so low that there is a risk for deep discharging the battery, it shuts down the test. All values are stored and can easily be transferred via an USB-stick to a PC for evaluation. Testing can be carried out without disconnecting the battery from the

ACTOM’S DUAL-VOLTAGE VOLTAGE TRANSFORMERS THE MOVE by several major metropolitan municipalities towards raising the transmission voltage for substations from 88 kV to 132 kV has prompted ACTOM High Voltage Equipment to develop a dual-voltage voltage transformer (VT) to facilitate the transition at minimal cost to users. “The conversions due to be implemented by various electrical authorities will involve a process whereby substations that are to be converted need to operate at 88 kV for a period until the conversion to the higher voltage level of 132 kV has been completed,” explains Etienne Venter, the division’s Design Engineer. “Consequently if an 88 kV substation is to be converted into a 132 kV facility, it requires replacing the existing 88 kV VTs with 132 kV units. We have overcome this stumbling block by developing the new dual-voltage VT, which provides for a seamless changeover from the lower to the higher voltage without the customer having to incur the extra cost of replacing existing units with higher rated ones.” A number of the new VTs are to be installed in the 88 kV/11 kV Roosevelt Park substation currently being extended and refurbished in the Johannesburg suburb of that name by Midrand- based substation contractors, F&J Electrical. The company placed an order with ACTOM High Voltage Equipment in January this year for six units, along with 21 x 132 kV current transformers, for the project. Design of the new VT commenced late last year. “What enabled us to develop it as speedily as we have is that the bulk of the design was based on the already proven design of the 132 kV compact VT we developed and introduced into the market in 2015,” says Venter. “This meant that most of the components had already been tested, so only a limited number of components in the dual-voltage unit needed to be put through the full battery of tests normally required on a newly-designed product.”

Enquiries: info@power-star.co.za

Enquiries: +27 (0)11 820 5369

SPARKS ELECTRICAL NEWS

OCTOBER 2017