Load throw-off management

1. Intro

Given the following context:

• Multiple consumers
• Some consumers require constant electrical supply
• Others have a variable need for electrical supply

The load throw-off feature helps manage the electrical supply distribution in that context. Following are some example scenarios to help introduce the feature in more detail.

2. Example scenario 1

A factory operates a staff canteen and provides 10 EV chargers for company fleet cars. Both facilities operate with the same contract, encouraging load limits of 3 x 250A. During service hours, the kitchen consumes up to

150A on L1 100A on L2 and 100A on L3.

A signal is provided when the kitchen is not busy, and consumption falls below 10A.

• The EV charging infrastructure may consume 240A when the kitchen is not busy (=250A – 10A)
• As soon as the kitchen is not used, the control electronics provides a 12V DC signal and the full 3 x 240A may be used by the DLM system.
• When the kitchen is in use, the load of

  L 1	L 2	L 3
  140A	90A	90A

  needs to be thrown off to not exceed the 3 x 250A limit. In that case the DLM may only consume

  L 1	L 2	L 3
  100A	150A	150A

  .

2.1. Configuring the Master Charge Controller

1. Apply the following configuration:

Location in Configuration Interface	Parameter	Value
Load Management > Dynamic Load Management	Dynamic Load Management - DLM Master/Slave	DLM Master (With internal DLM-Slave)
	EVSE Sub Distribution (L1/L2/L3)[A]	L 1 L 2 L 3 240 240 240
	External Input 1 Config	Enable Opto 1 in
	External Input 1 Polarity	Active low
	External Input 1 Current Offset	L 1 L 2 L 3 -140 -90 -90

2. At the bottom of the Configuration Interface, click , then click to apply the changes

2.2. Configuring the Slave Charge Controller

1. Apply the following configuration:

Location in Configuration Interface	Parameter	Value
Load Management > Dynamic Load Management	Disconnected Limit [A]	10

2. At the bottom of the Configuration Interface, click , then click to apply the changes

3. Example scenario 2

A grid operator uses ripple control to throw-off loads. In this example, one (or multiple) 22kW wall-box must reduce load to 3 x 7A (5kW), when a control signal is low.

3.1. Configuring the Master Charge Controller

1. Apply the following configuration:

Location in Configuration Interface	Set Parameter	to
Load Management > Dynamic Load Management	Dynamic Load Managemen - DLM Master/Slave	DLM Master (With internal DLM-Slave)
	EVSE Sub Distribution Limit (L1/L2/L3)[A]	L 1 L 2 L 3 32 32 32
	External Input 1 Config	Enable Opto 1 in
	External Input 1 Polarity	Active low
	External Input 1 Current Offset	L 1 L 2 L 3 -25 -25 -25
	Disconnected Limit [A]	7

2. At the bottom of the Configuration Interface, click , then click to apply the changes

3.2. Configuring the Slave Charge Controller

1. Apply the following configuration:

Location in Configuration Interface	Parameter	Value
Load Management > Dynamic Load Management	Disconnected Limit [A]	7

2. At the bottom of the Configuration Interface, click , then click to apply the changes

4. Limitations of the Load throw-off function

• The load can only be reduced instantly and not gradually over a time interval
• With DLM active, only the current can be reduced, not the power (reduction 32A 🡒 7A, but not 22kW 🡒 5kW)