Oztek Blog

Using Modbus to Communicate with Multiple OZpcs-RS40s

Posted by Dave Zendzian on Mar 3, 2021 8:43:13 AM

The OZpcs-RS40 is a 40kW Power Conversion System (PCS) intended for battery-based energy storage applications. The PCS is designed to be mounted in a standard 19” rack, and easily paralleled to scale power capability. All hardware interfaces are located on the front panel, utilizing pass-through type terminal blocks for simple daisy chained cable or bus bar power connections. Similarly, the Modbus and digital I/O signals are provided on redundant, high density, 15-pin D-Sub connectors, which also allow for simple daisy chain cabling. When using Modbus to control multiple, paralleled PCS there are several things to consider, including termination, addressing, and broadcast messaging.

Read More

Topics: Grid Tie Inverter, Digital Power Control, energy storage, MODBUS, Smart Inverter, UL1741-SA

Frequency/Watt Smart Inverter Functionality

Posted by Dave Zendzian on Feb 1, 2021 12:02:05 PM

In a previous post, I discussed how the Volt/VAR function can be used to provide grid voltage stabilization during over and under-voltage conditions. In addition to stabilizing out of tolerance voltage conditions, over and under-frequency grid conditions can also be mitigated using Frequency/Watt functionality. In a manner similar to Volt/VAR, the Frequency/Watt function will automatically generate real power commands based on grid frequency measurements.

Read More

Topics: Grid Tie Inverter, Digital Power Control, energy storage, Smart Inverter, UL1741-SA

Volt/VAR Smart Inverter Functionality

Posted by Dave Zendzian on Dec 23, 2020 4:41:47 PM

To support grid voltage stabilization during over and under-voltage conditions, UL1741 certified smart inverters, such as the OZpcs-RS40, can be configured to automatically absorb or inject reactive power based on grid voltage measurements. This behavior is commonly referred to as Volt/VAR control and is implemented using a configurable array of points, that when combined, define a linear, piece-wise curve that results in the desired Volt-VAR behavior.

Read More

Topics: Grid Tie Inverter, Digital Power Control, energy storage

What is MESA/SunSpec?

Posted by Dave Zendzian on Mar 31, 2017 1:26:20 PM

Traditionally, grid energy storage systems (ESS) have been one-off solutions, utilizing proprietary software and hardware components.  As such, each installation requires time consuming, custom integration.  Often times proprietary vendor hardware or software protocols require "hacks" to get all components to play nice.  Ultimately this approach results in higher costs, decreased reliability, and limited scalability and upgrade options.

Read More

Topics: Grid Tie Inverter, power inverter, Power Conversion, energy storage, MODBUS

Grid Energy Storage Is a Growth Industry to Watch

Posted by John O'Connor on Sep 20, 2011 8:56:00 PM
energy grid storageThe market for grid energy storage is robust and growing. According to a study published by GTM Research, the U.S. market for utility-scale grid storage is expected to rise from an annual value of about a quarter of a billion dollars in 2009 to about $2.5 billion by 2015.

The potential exists for continued rapid growth in this market in the United States and worldwide. Demand will be filled by companies pursuing a variety of technologies to fill the needs of the power grid.

What is Grid Energy Storage?

In an ideal energy world, demand for electric power would be matched exactly by electric power supplied, with no need for backup power sources or storage anywhere in the grid. But, in the real world, demand and supply are often mismatched.

Demand for electric power varies by time of day and changes with every season. Power supply varies based on many factors, including plant downtime, changes in fuel supply and prices, and the intermittent nature of renewable energy sources such as wind and solar.
The imbalance between demand and supply is evened out by various technologies that store energy and make it available to the grid as it is needed. With the rise of the "smart grid" and the increasing importance of renewable energy sources, the demand for grid energy storage and the complex technologies that supply it is large and growing.
Read More

Topics: energy storage